Research completed January 2026

DOI: https://doi.org/10.7488/era/7244

Executive summary

Aims

The Carbon Neutral Islands (CNI) project was launched in 2021 to support six Scottish islands – Hoy, Islay, Great Cumbrae, Raasay, Barra, and Yell – in achieving carbon neutrality by 2040. This research explores what the CNI project has achieved so far and investigates what is realistically achievable, with a view to establishing an appropriate framework for measuring progress. Options for developing the project to achieve greater and more sustained decarbonisation impact in the future are also considered.

Key Findings

Through CNI capital funding, islands have expanded access to low‑carbon mobility, improved energy efficiency, increased renewable generation deployment, strengthened local food production, and enhanced climate resilience. Collectively, the CNI project demonstrates a scalable and replicable model for island‑led climate action, with lessons actively shared to support wider uptake across Scotland’s islands.

The activities that have been undertaken by the CNI project cover nine theme areas:

• Energy efficiency and low-carbon heating
• Renewables
• Low-carbon transport
• Nature-based solutions
• Circular economy
• Climate literacy
• Collaboration and capacity
• Data and knowledge
• Low-carbon food supply

Across these theme areas, the CNI project has encountered a range of barriers that influence delivery and outcomes. Some of these barriers fall within the project’s scope of direct influence, including, high costs, data gaps, limited availability of on‑island skills, and knowledge gaps. Other barriers lie beyond the project’s direct sphere of influence and are more structural in nature such as those associated with island geography and climate, limited existing infrastructure capacity, current national and local policy frameworks as well as flexibility on how funding is structured. Understanding the distinction between these groups of barriers is critical for targeting effort, shaping expectations, and identifying where the project can drive meaningful impact. Co-benefits resulting from the project serve as a lever for embedding lasting community support for decarbonisation.

Success for the CNI Project

We evaluate what success looks like by considering specific activities for each theme covered by the CNI project. These include but are not limited to:

Energy efficiency and low-carbon heating:

• Completing energy audits for all buildings.
• Support for completing EPC assessments and retrofit works.
• Upskilling communities in the maintenance and monitoring of new installations.

Renewables:

• Increasing the number and efficiency of solar installations by standardising these installations and installing via a programme where possible.
• Ensuring total cost of ownership of installations is considered.
• Accessing funding for installations from sources beyond the CNI Project.

Low-carbon transport:

• Expanding EV charger networks and electrified community transport fleets.
• Improving the quality and utilisation of public transport on islands.

Nature-based solutions:

• Upskilling for land and coastal management to support carbon sequestration and restoration of nature and ecosystem functions.
• Testing and learning from nature-based solutions through pilot projects.
• Engaging with landowners, farmers, crofters to build trust and share knowledge.
• Supporting on-island nature organisations to upscale restoration with involvement from residents and volunteers.

Circular economy:

• Supporting community re-use, repair hubs, and community composting.
• Investigating the potential for intra and inter-island scaling up and lessons learned.
• Education campaigns to maximise what waste can be processed sustainably on islands.
• Engagement with councils and waste management companies to shape future island waste management.

Climate literacy:

• Supporting climate literacy activities such as additional training and development of materials.
• Ensuring climate literacy strategies reach beyond schools and include older generations.
• Enhancing the CNI grant application to require demonstration of intergenerational community involvement.

Collaboration and capacity:

• Reviewing and defining the governance structures further including the role of the CDO, the supporting Council officers, and the collaborative role between them.
• Developing agreed island monitoring frameworks that include community co-benefit metrics which present success to the communities.

Data and knowledge:

• A centralised hub for data collection, knowledge sharing and lessons learned.
• A centralised technical leadership role for the CNI project to guide islands in their next steps and take islands from CCAPs to impactful implementation.

Low-carbon food supply:

• Supporting a variety of small-scale island pilots to demonstrate the capacity of securing low-carbon food for the islands.
• Documenting and sharing knowledge across islands of both successful and unsuccessful projects to avoid duplication and enhance institutional knowledge.
• Review the long-term value of investing in these projects.

Recommendations

We suggest a widening of how success is defined and delivered and to ensure knowledge and experience is shared widely:

• Include co-benefit metrics to highlight wider project success as these embed in communities long-term continued support for the aims of the project.
• Enhance coordination and visibility of existing technical knowledge learning functions.
• Programming support to help progress from planning to action and strengthen overall impact.
• Piloting and knowledge capture.
• Using the theory of change framework for project and policy design.
• Developing a monitoring and impact framework.

Next steps

We also propose a long list of potential indicators and a theory of change for each of the nine theme areas across three time horizons (to 2030, to 2035, and to 2040). These indicators are only intended to serve as a starting point for dialogue. Ultimately what can be implemented from the list will depend on project capacity and other contextual factors.

There is significant potential for the next phase of the CNI project to deliver even greater impact by defining and demonstrating the next stage of successful community-led climate action for island decarbonisation and community resilience. This includes widening the scope of what is tracked and communicated – elevating co‑benefits alongside carbon outcomes – to better showcase the full value of the project and inspire other communities.

Glossary/Abbreviations table

Introduction

The Carbon Neutral Islands (CNI) project was launched under ‘A Fairer, Greener Scotland: Programme for Government 2021–22’ to support six Scottish islands – Hoy, Islay, Great Cumbrae, Raasay, Barra, and Yell – in achieving carbon neutrality by 2040. This initiative contributes directly to Scotland’s statutory target of reaching net zero by 2045 and reflects national priorities around climate action, energy transition, and inclusive economic development.

The project supports key commitments within both the National Performance Framework and the National Islands Plan, focusing on climate mitigation and adaptation, clean and secure energy, and the creation of island-based jobs. The CNI project is guided by three core principles:

1. Alignment – ensuring efforts complement existing local and national climate initiatives
2. Justice and Inclusion – embedding a just transition and community-led approaches
3. Sharing – applying standardised methodologies to enable replication and knowledge exchange across island communities

To deliver on these principles, the project adopts a bottom-up governance model, employing Community Development Officers (CDOs) through local anchor organisations. These CDOs work closely with community representatives to foster engagement and build trusted relationships. Given the interconnected nature of island economies – encompassing sectors such as agriculture, transport, energy, tourism, and governance – this approach helps to maximise the impact of local climate initiatives.

CNI Project Successes and Positive Impacts

To date, the CNI project has delivered carbon audits, Community Climate Change Action Plans (CCAPs), community engagement activities, and knowledge exchange. In addition, the CNI project has developed finance roadmaps (Scottish Government, 2025) for each island to support long-term sustainability, including the exploration of innovative finance business models and public–private partnerships.

Building on this groundwork, the CNI project has achieved substantial progress by implementing practical, community-driven decarbonisation projects with wide-ranging environmental and social benefits. These projects funded under the CNI capital fund have enabled the building of local capacity and span transport, energy, food systems, biodiversity, and climate resilience. For example, as outlined in the CNI Project Progress Report (Scottish Government, 2024), islands such as Hoy & Walls and Barra have expanded access to low‑carbon mobility through e‑bike programmes and shared electric vehicles. Significant investments into energy efficiency and renewable generation projects have been made, for example, Islay has advanced a fully funded community solar array alongside wider biodiversity and sustainable fuel initiatives. There have also been advances in local food production and land stewardship, with community growing initiatives delivered across Cumbrae, Barra, and Yell. At the same time, the islands are strengthening climate resilience through measures such as Yell’s community resilience hubs and Cumbrae’s flood protection work. To illustrate the depth of the impact of the CNI project, a selection of case studies has been produced and are available in Appendix D. A summary of the case studies is shown in Table 1.

Collectively, the project has delivered measurable environmental benefits while enhancing economic wellbeing, strengthening social cohesion, and building long-term resilience across Scotland’s islands. The project now serves as a replicable model for wider island communities, with lessons actively shared across Scotland to support broader climate action and ensure that all islands can benefit from the approaches developed through the project.

Research Aim and Objectives

While the CNI project has been a significant driver across the six islands, some actions identified in the island CCAPs are constrained by factors beyond the islands’ control, such as mainland grid connections and transport links, which are tied to non-devolved government policies. These systemic barriers limit what decarbonisation actions the CNI project can directly influence. Given these circumstances, it is important that, when measuring the progress of the CNI project, realistic expectations are set with respect to the net zero deliverables that can be achieved.

This research aims to define what is realistically achievable through the CNI project and to establish a framework for measuring progress. Specifically, this report addresses the following questions:

• What specific outcomes or deliverables can realistically be achieved within the scope of the CNI project?
• What does ‘good’ look like in terms of these outcomes and progress towards net zero for the islands?
• What metrics can be used to measure the success of the CNI project and its associated activities?
• What systemic barriers to decarbonisation exist, and how can they be addressed within the scope of the project?
• How can the Scottish Government’s Islands Policy Team set realistic expectations and communicate the project’s scope effectively?
• What insights and case studies can inspire future programmes across other island communities?

The resulting evidence will support Scottish Government’s Islands policy team to communicate the CNI project scope more clearly, to identify realistic metrics for success, and to inspire future island decarbonisation efforts, while working in close collaboration with the islands.

Table 1: Summary of the impacts of case study projects

Theory of Change (ToC)

To answer the aforementioned questions, a Theory of Change (ToC) framework has been developed. A ToC framework provides a structured, participatory approach to understanding the specific outcomes an intervention seeks to achieve, and for whom. It maps causal pathways linking activities to long-term goals, while interrogating the assumptions that underpin these pathways. It captures core insights, including:

• Key stakeholders impacted by CNI
• Activities undertaken by CNI
• Short, medium, and long-term outcomes
• External factors shaping CNI’s impact, including enablers and systemic barriers
• Assumptions underpinning CNI’s narrative of change

Presented in Sections 5 and 6, the ToC framework has informed the analysis and findings, clarifying the key pathways of change that the CNI project seeks to achieve. It has also guided the responses to the research questions and the development of recommendations to address systemic barriers to decarbonisation. The ToC provides the analytical foundation to help determine what is achievable and what success looks like for the CNI project.

Methodology

The methodology comprised of four key steps: (1) desk-based research and the development of a draft ToC, (2) stakeholder engagement and validation, (3) finalisation of ToC and report development, and finally (4) development of case studies (see Appendix A for the full methodology).

1. Comprehensive desk‑based review of 35 CNI publications, technical assessments, carbon audits, and relevant academic and grey literature provided the evidence base for drafting the initial ToC and responding to the research questions.
2. Seventeen structured interviews were conducted with national stakeholders, local authorities, and Community Development Officers (CDOs) across the six islands. These discussions were used to test and refine the ToC logic, explore systemic barriers and enablers, and assess data availability. Stakeholders validated the draft ToC collaboratively using an interactive Mural whiteboard, and thematic analysis of interview insights informed further refinement.
3. Evidence from the desk‑based research and interviews was synthesised to finalise the ToC and develop the report. Interim findings and proposed recommendations were tested with the Scottish Government Steering Group, ClimateXChange, and CDOs to ensure alignment with both national priorities and community needs.
4. Finally, four illustrative case studies were developed to highlight examples of progress and practical lessons emerging from the CNI project (see summary Table 1 and Case Studies). These drew on desk-based evidence, interview insights, and targeted data requests to CDOs, with each case study reviewed and approved by the relevant island representative.

Limitations relating to the scope of stakeholder engagement, reliance on existing documentation, and variations in data availability across islands are acknowledged in Appendix A.

CNI Theory of Change Framework

Overview

The desk-based research provided the initial context for shaping the CNI project ToC framework. Drawing on the available project literature, nine themes were identified that represent the breadth of activities and inferred priorities across the islands. These nine themes are:

• Energy efficiency
• Community‑owned renewables
• Low‑carbon transport
• Nature‑based solutions
• Circular economy
• Climate literacy
• Governance and capacity
• Data and knowledge
• Low‑carbon food supply chains

The nine thematic areas have each been mapped into a dedicated ToC diagram in Appendix B. These diagrams visually illustrate the activities associated with each theme, the key stakeholders involved, and the anticipated short, medium, and long-term outcomes that collectively contribute to the overarching goal of achieving carbon neutrality by 2040.

Each diagram is structured horizontally, allowing readers to follow the progression from activities through to outcomes over time. Additional contextual information is integrated into the diagrams, including barriers and enablers. The key components within the ToC outcome pathways are defined in Table 2.

Table 2: Core ToC components and their description.

Co-benefits are noted in Table 3 and include wider social, economic, and environmental benefits.

Table 3: Co-benefit categories across outcome pathways.

Once drafted, the ToC pathways were validated through stakeholder engagement to refine the pathways under each key theme. This validation expanded the ‘missing middle’, the intermediate steps between activities and long-term outcomes, and clarified the linkages, barriers, and enablers that connect project activities to the outcomes they aim to achieve. These insights were critical in shaping the refined outcome pathways and informing recommendations on how to define ‘what success looks like’ for CNI.

For more information on the methodology, see Methodology chapter in Appendix A which details the key documents evaluated during the desk-based review and the list of stakeholders who participated in the validation interviews.

Systemic barriers

Figure 1: Tiered structure of systemic barriers.

Through stakeholder validation of the ToC framework, it was identified that the barriers to achieving carbon neutrality operate at different levels of influence and geographic scope. Figure 1Figure 1 illustrates this tiered structure, indicating where the CNI project can exert influence and where constraints are largely beyond its control. This layered approach helps clarify why some outcome pathways offer stronger leverage to achieving carbon neutral islands, while others remain constrained by systemic factors.

At the base of the structure sit barriers that are beyond the CNI project’s direct influence. These include physical, infrastructural, and institutional constraints that shape what is possible across multiple pathways.

Island geography and climate are fundamental barriers, whereby short growing seasons limit progress on low-carbon food initiatives, while remoteness and harsh weather complicate basic logistics regarding getting contractors and materials to the islands. Weather also dictates when work can be carried out, adding unpredictability to programming.

Infrastructure capacity – particularly grid limitations – emerged from the stakeholder engagement as a significant constraint. Without national-level investment in grid capacities, islands cannot connect new renewables which hinders how far the community-owned renewables pathway can go.

Funding cycles were repeatedly highlighted by stakeholders as a major concern. Stop-start funding and uncertainty about future support undermine confidence and prevent scaling, particularly for activities like nature-based solutions (NbS) and community renewables that require multi-year commitments. This is a critical barrier that falls outside of the CNI direct control.

In addition, institutional factors, such as national and local policy frameworks, strongly influence what can be delivered by the CNI project. Legacy policies, such as the crofting regulations, for example, shape the feasibility of NbS and require careful consideration to align with programme goals.

Higher up the structure are systematic barriers that the CNI project has the potential to mitigate against through programme design and delivery.

Costs – both capital and human – are a key systemic challenge. Capital support is needed for many activities, including funding retrofits, low-carbon transport infrastructure, or installing renewables. CNI funding is pivotal for getting these projects off the ground due to the inherent expense of materials, technology, and infrastructure.

Finally, knowledge gaps, data gaps, and on-island skills shortages intersect to slow progress. Data for the projects often relies on national proxies rather than island-specific baselines, reducing trust and slowing decisions. Skills shortages mean reliance on external contractors for works, adding an “island premium” to costs. Equally, procurement rules requiring specialist accreditations (e.g., Microgeneration Certification Scheme (MCS)) can exclude local contractors, limiting opportunities for upskilling and reducing costs. Knowledge gaps on how best to deliver projects and activities on the islands can also stall delivery due to a lack of confidence in how to proceed, particularly around complex issues of how to manage different landscapes and ecosystems. Equally, a lack of capability in designing projects that apply for grant funding, such as not considering maintenance costs in grant requests have led to projects that start but cannot be sustained – for example, community wind turbines funded prior to the CNI project have been taken offline due to unaffordable upkeep. These are areas where the CNI project could play a role in supporting training and accreditation.

It is also important to recognise that these barriers vary in geographic scope and intensity. Some are universal across islands, while others are highly localised. Proximity to the mainland, transport links, and physical geography all have an influence on challenges such as material delivery, contractor availability, and waste removal. Understanding this variation is essential for tailoring solutions and prioritising resources.

CNI Theory of Change

For each of the nine theme areas that underpin the CNI project, a dedicated ToC pathway has been developed. The pathways illustrate:

• Key CNI project activities associated with the theme.
• Stakeholders involved in delivery.
• Anticipated short, medium, and long-term outcomes contributing to the overarching goal of carbon neutrality by 2040.
• Barriers and enablers identified through stakeholder engagement.
• Co-benefits, highlighted using a colour-coded system to show wider social, economic, and environmental impacts (see Table 3).

ToC diagrams have been used to illustrate each pathway in a clear, visual format, linking activities, stakeholders, outcomes, barriers, enablers, and co-benefits. Each diagram highlights the following barriers:

• Clustered barrier (common amongst multiple pathways).
• Specific related barriers cited in stakeholder interviews.
• Structural barriers (outside the control of the CNI Project).

The associated barriers to implementing the short, medium and long-term outcomes have been colour-coded: yellow rectangles represent clustered barriers and pale orange rectangles denote specific related barriers cited in the interviews. Red rectangles indicate structural barriers that cannot be addressed within the scope of the CNI Project.

ToC pathways for all theme areas contained in Appendix B.

This granularity grounds the analysis in the practical realities of implementation across the six islands and helps answer the following critical questions:

• What specific outcomes or deliverables can realistically be achieved within the scope of the CNI project?
• What does ‘good’ look like in terms of these outcomes and progress towards carbon neutrality for the islands?
• What metrics can be used to measure the success of the CNI project and its associated activities?
• What systemic barriers to decarbonisation exist, and how can they be addressed within the scope of the project?

Key Findings & Recommendations

Defining success across each theme

It is recognised that both systemic and theme-specific barriers significantly influence what the CNI project can achieve. While some themes face inherent limitations, others offer greater scope to deliver impactful activities – reducing carbon emissions and equally enhancing quality of life for residents through the delivery of co-benefits. This section illustrates what success could look like across each theme, highlighting where opportunities for deeper progress exist. It also provides suggested timeframes for implementation.

Energy efficiency and low-carbon heating

Upscaling the rate of installations across homes, community buildings, and businesses is already a core focus of the CNI project, delivering significant benefits for its objectives, with further opportunities to build on this work as delivery progresses. See Case study: Decarbonising community spaces for a case study on decarbonising community spaces in Barra and Vatersay, showcasing energy efficiency benefits delivered through the CNI project.

Success looks like:

• Ensuring all homes/community buildings/businesses have an energy/retrofit audit.
• Supporting CDOs/on-island organisations create intra and inter-island programmes for getting EPC assessments completed to support future grant applications.
• Supporting CDOs/on-island organisations establish programmes for energy / retrofit works.
• Investigating upskilling island businesses and residents in maintenance and monitoring to support servicing of low-carbon and energy efficient installations.

Optional support beyond the stated goals of the CNI project could include:

• Supporting residents with access to funding, this could be external funding (such as HES), or as part of the CNI application process.
• For external funding sources, CNI could support residents with completing applications, working with HES to simplify applications reflecting resident feedback, providing guidance on available funding to residents. For CNI funding, the project could improve uptake through simplifying requirements of households, providing on and offline support (drop-in sessions).
• Investigate topping up funding from external sources (such as HES) where ‘missing middle’ homes or in-fill homes may be excluded, as possible with other grant funding programs like the Warm Homes Fund.

Indicative Timeframes

Actions under this theme could likely start to mobilise over the short-term and can build on momentum and capacity already established across the islands. Initial steps such as outreach to establish auditing and EPC programmes, could begin relatively quickly (short term: 0-3 years), while establishing intra- and inter-island retrofit programmes will likely require medium-term planning (3-5 years). Longer-term actions (5+ years) include overall scaling of installations and establishing upskilling programmes relating to maintenance and monitoring capacity. Actions regarding funding applications are likely to be required throughout the project as funding processes develop.

Renewables

Building on existing delivery, the CNI project already focuses on the roll‑out of decentralised solar PV across islands and on supporting communities to develop and implement future‑proofed community renewables. This remains a core theme of the project, with scope to strengthen and scale activity as delivery progresses. See Case study: Millport buildings solar PV and battery installations for a case study on implementing community renewables in Cumbrae, delivered through the CNI project.

Success looks like:

• Ensuring all homes/community buildings/businesses are assessed for suitability for solar PV.
• Supporting CDOs/on-island organisations develop intra and inter-island programmes for solar installation.
• Supporting CDOs/on-island organisations develop standardised island-context renewable specification to standardise and simplify application processes – such as the success story on Cumbrae (see Appendix 10.11).
• Ensuring community renewables project applications have considered future maintenance costs in their assessment of long-term viability. This also involves upskilling grant seekers/those assessing the grant award process to future-proof applications. Applications without consideration of maintenance and future should not be approved without these considerations.
• Reviewing the viability of existing community renewable assets that have been taken offline, supporting those deemed future-proofed with getting back online.
• Engaging with wider organisations that support renewables (community and domestic) such as CARES and HES to facilitate island access to wider funding.
• Developing a programme of support across multiple locations that might bring economies of scale in procurement and delivery.

Indicative Timeframes

Actions to support decentralised solar PV and community renewables will likely need to progress in stages. Immediate priorities (short term: 0-3 years) include assessing homes, community buildings, and businesses for solar suitability. Medium-term actions (3-5 years) focus on developing standardised island-specific renewable specifications, supporting CDOs to establish coordinated installation programmes, and reviewing viable existing assets. Longer-term actions (5+ years) include overall scaling of installations and establishing upskilling programmes relating to maintenance and monitoring capacity. Actions regarding internal and external funding applications are likely to be required throughout the project as funding processes develop.

Low-carbon transport

Building on existing delivery, the CNI project could continue to focus on financial support for proven transport technologies, such as EV chargers, EV buses, and EV taxis as well as facilitating knowledge sharing from leading islands with transport decarbonisation success, e.g., Hoy, to replicate models across islands. See Case study: Community transport electrification for a specific case study on electrifying Hoy’s bus fleet, delivered through the CNI project.

Success looks like:

• Providing capital funding for expanding EV charger networks and EV community buses or EV taxis to on-island operators.
• Ensuring learnings are shared from successful island projects – particularly the Hoy community EV bus – to enhance replication across islands, including ongoing support for assessing the viability of a Hoy-based model for community transport on other islands.
• Assessing the business model and technical barriers towards implementation across other islands based on the Hoy critical success factors
• Engaging with Councils and other on-island transport operators on improving reliability and regularity of public transport to enhance usage.

Indicative Timeframes

For low-carbon transport, the immediate focus could be knowledge sharing from the successful implementation of the community EV bus in Hoy. As part of this, gathering data and community insights into the technical and business model barriers that exist for other islands could help to inform programme design and replication across islands (short term: 0–3 years). Capital funding for EV chargers, community EV buses, and taxis should begin early and continue through the short to long term (0–5+ years) as projects arise and readiness improves. Engagement with Councils and transport operators to enhance reliability and regularity of public transport could be treated as an ongoing activity throughout the project to maximise uptake and ensure long-term success.

Nature-based solutions

The CNI project could continue to focus and scale increasing on-island knowledge and capacity in nature-based solutions and land management approaches to build momentum and inspire collective change. Pilot projects should be showcased and lessons learned shared to foster confidence in methods and the gathering of on-island datasets. See Case study: Invasive Species (Rhododendron) Removal for a specific case study of a CNI project addressing invasive species in Raasay.

Success looks like:

• Improving knowledge and upskilling on-island capacity for land and coastal management methodologies that support carbon sequestration and the restoration of nature and ecosystem functions across the breadth of island landscapes.
• Supporting a wide variety of pilot projects to be testbeds and experiments that allows a learning by doing approach and builds evidence for what works on the islands.
• Engaging widely with landowners, farmers, crofters to build trust and share pilot project and case study knowledge.
• Engaging with and supporting on-island nature organisations (e.g., RSPB Scotland) to upscale restoration and promote action amongst volunteers.
• Facilitating upskilling of on-island residents through engagement with wider nature restoration and land management organisations, such as Rewilding Scotland Alliance and Scotland the Big Picture.

Indicative Timeframes

Activities within the nature-based solutions theme could all be implemented across an ongoing timescale. A first priority is identifying gaps in knowledge and collecting on-island datasets to inform future restoration and land management approaches (short term: 0–3 years). Upscaling and establishing new pilot projects could be delivered across the medium term (3-5 years) as foundational knowledge and local datasets are established to build confidence and evidence. Establishing knowledge-sharing practices, engaging with landowners and farmers, and upskilling residents through partnerships with wider restoration networks could be treated as ongoing activities throughout the project.

Circular economy

The CNI project could continue to focus on supporting community waste management projects that are successful in island contexts, such as re-use/repair/composting schemes. Equally, the CNI project should facilitate a stronger relationship between island activities and the island councils that control waste management to align best practices.

Success looks like:

• Supporting island schemes that have demonstrated success including community re-use, repair hubs, and community composting.
• Investigating the potential for intra and inter-island scaling up of these schemes and providing lessons learned to islands to prioritise those that work in an island-context.
• Facilitating the relationship between island waste management practices and council waste management processes. Councils have overall control of waste management and island practices should be aligned to maximise what can be processed sustainably. Education campaigns should be delivered to align and maximise synergies here.
• Engaging with councils and waste management operatives to understand how council waste management processes can be expanded and providing them insight into the island-context to shape future island waste management.

Indicative Timeframes

Actions to support community waste management should span the short- to medium-term (0-5 years). The immediate priority is identifying successful island schemes and investigating opportunities for scaling up, alongside starting to facilitate stronger relationships between island practices and council waste management processes. Successful pilot initiatives such as re-use, repair hubs, and composting could be supported early and upscaled over the medium- to long-term. Education campaigns and engagement with councils and waste operatives should be treated as ongoing activities throughout the project to ensure alignment and maximise sustainable processing.

Low-carbon food supply

The CNI project could continue to focus on demonstrating what can be achieved by supporting pilot projects and ensuring lessons learned are shared to avoid wasted effort. Systemic barriers prevent this theme from delivering large scale carbon reductions or changing significantly how communities can access and consume local food. Resources should be spent demonstrating what works, at what scale and supporting smaller-scale transformations.

Success looks like:

• Supporting a variety of small-scale island pilots, (e.g., community allotments, polycrubs) to demonstrate the capacity of securing low-carbon food for the islands and where these systems might be appropriate in an island-context.
• Documenting and sharing knowledge across islands of successful and unsuccessful projects to avoid duplication and enhance institutional knowledge.
• Acting in a guidance and evaluation role to review the long-term value of investing in these projects.

Indicative Timeframes

For the low-carbon food theme, actions could likely span the short to medium term (0-5 years). The immediate priority is launching small-scale pilot projects, building on those already in existence on the islands – such as community allotments and polycrubs – to demonstrate what works and to gather evidence. Documenting and sharing lessons learned should be an ongoing activity throughout the project to avoid duplication and strengthen institutional knowledge. The action for CNI to act in a guidance and evaluation role could begin early and continue into the medium- to long-term to shape future activities as pilots mature, ensuring resources are directed toward approaches with proven impact.

Climate literacy

The CNI project could continue to focus on engaging all generations within activities delivered under the project and supporting CDOs/on-island organisations with delivering widescale climate literacy programmes.

Success looks like:

• Ensuring strategies for climate literacy do not just focus on schools but also reach older generations. Island populations have an older demographic and so reaching and establishing climate literacy in island citizens should prioritise reaching these groups.
• Providing resource to support activities that enhance the spread of climate literacy, this could be additional training, development of materials, or support with programming across islands.
• Enhancing the CNI grant application to demonstrate intergenerational community involvement. The application already requires documentation of what percentage of island communities were involved in developing the activity/project, the CNI project could also require applications to document what efforts were taken to include all demographics within project design to highlight the importance of intergenerational involvement and education.

Indicative Timeframes

Activities to enhance climate literacy and intergenerational engagement could begin immediately and continue throughout the short to medium term (0-5 years), with a view to enhance capacity and institutionalise climate literacy in the longer-term. The first priority could be to develop strategies and resources that reach all demographics, particularly older generations, alongside schools. Providing training, materials, and programming support should be treated as an ongoing activity across the short- to medium- term to ensure widespread uptake. Enhancing the CNI grant application process to require documentation of intergenerational involvement can be introduced early, with accompanying guidance, and maintained as a continuous requirement to embed inclusive practices.

Collaboration & capacity

The CNI project could continue to focus on formalising the governance structure of the project to enhance clarity of roles, responsibilities, and strengthen capacity for collaboration. This should expand into how the CNI project and success metrics will be monitored.

Success looks like:

• Reviewing and defining the governance structures further, this should include the individual roles of the CDO, the supporting Council officers, and the collaborative role between these entities. These could be co-developed and formalised through a Memorandum of Understanding (MoU) or other appropriate governance mechanisms.
• Developing agreed island monitoring frameworks that include community co-benefit metrics which present success to the communities.

Indicative Timeframes

Formalising governance structures and developing monitoring frameworks should be prioritised in the short term (0-3 years) to provide clarity of roles and responsibilities and strengthen collaboration early in the project. This includes co-developing and agreeing mechanisms such as MoUs between CDOs and Council officers. Establishing the island monitoring frameworks with community co-benefit metrics should follow closely and be completed within the medium term (3–5 years), with ongoing refinement as the programme evolves. More information on the immediate steps for the monitoring and impact framework can be found in Section 7.3.

Data & knowledge

The CNI project could continue to focus on enhancing the availability of on-island datasets across each theme by capturing relevant island data, technical knowledge, and pilot project learnings in a centralised hub and ensuring future project design is informed and adapted to learnings. This could be managed by the centralised knowledge leader role(s) as discussed in Section 7.3. In addition, enhancing the capacity of CDOs/on-island organisations to track progress and calculate impact from activities to demonstrate the success of the CNI project to stakeholders and communities.

Success looks like:

• Available relevant island data across themes and islands that allows project design to be informed by lessons learned and ground-truthed datasets. This should be accompanied by non-technical guidance, methodologies, and use-cases for the data to enhance project design and support island capacity.
• A centralised hub for data collection and knowledge sharing that is accessible to island communities.
• A centralised technical leadership role for the CNI project to guide islands in their next steps and take islands from CCAPs to impactful implementation. This role is further explained in Section 7.3.

Indicative Timeframes

Enhancing the availability of on-island datasets and establishing a centralised knowledge hub should be prioritised in the short term (0–3 years) to ensure future project design is informed by lessons learned and ground-truthed data. Establishing the knowledge hub and appropriate mechanisms for data sharing will likely need to be an iterative process and incorporate continuous improvement throughout the medium- to long-term. Developing non-technical guidance and methodologies to support island capacity should follow closely and continue through the medium- to long-term as knowledge develops (3–5+ years). The creation of a centralised technical leadership role and building CDO capacity to track progress and calculate impact should be treated as ongoing activities throughout the project to maintain consistency and demonstrate success to stakeholders and communities.

Overarching considerations

Co-benefits are inherent supporting outcomes of the CNI project that could be championed as wider goals

It became clear through the research and stakeholder engagement that the CNI project delivers far more than emissions reduction. The activities designed to support decarbonisation could also generate a wide range of potential co-benefits that strengthen island communities and improve quality of life.

These benefits are not incidental – they are integral to the success of the project and a critical lever for inspiring action. For those living on the islands and for the stakeholders implementing the project, these potential co-benefits are often more tangible and immediate than carbon metrics. They represent visible improvements in resilience, community capacity, and everyday life – while simultaneously reducing emissions. This dual impact is essential for maintaining embedded and lasting community support for carbon reduction initiatives in the project.

Co-benefits are already integral to the project, included as considerations in the CNI Capital Fund application and noted by CDOs as a key delivery mechanism – see 7.2.3. However, demonstrating success for the CNI project means elevating these co-benefits to tangible outcomes and intentions of the project. A thriving, resilient, and empowered island community is not just a desirable side effect – it is a necessary condition for achieving the CNI project’s overarching goal of carbon neutrality by 2040.

Defining success is a question of communication and audience

Defining success for CNI is equally a question of perspective – it depends on the audience. The project involves multiple stakeholders across different roles and responsibilities, including, but not limited to:

• Scottish Government – responsible for inception, funding, and policy alignment.
• Scottish Futures Trust – responsible for managing capital funding through CNI and project development.
• CDOs and delivery partners – responsible for implementation and coordination.
• Island communities and residents – both as participants and beneficiaries.
• Monitoring bodies – including Scottish Government and CDOs, tracking progress and reporting success.

For the Scottish Government, the measure of project success is primarily the progress made towards carbon neutrality. This reflects national climate targets and the project’s core purpose. However, the potential co-benefits delivered through CNI activities – such as warmer homes, reduced fuel poverty, and improved energy resilience – also contribute to wider national policy priorities across housing, health, and economic development. Communicating these links strengthens the case for continued investment and cross-departmental collaboration.

For the Scottish Futures Trust, success is delivery on their remit to manage the CNI capital fund and, as part of that, seeing that the community projects delivered through the fund contribute to the delivery of the CCAPs.

For CDOs and delivery organisations, success is also primarily defined by fulfilling their mandate: enabling their island to achieve carbon neutrality. Their focus is on practical delivery and overcoming barriers to implementation.

For communities and islanders, the picture is different. Carbon neutrality and emissions reduction are often seen as abstract concepts. What matters most is improving island life through better housing, affordable energy, reliable transport, enhanced community wealth, and resilience to climate change. These more tangible benefits are what success looks like at the local island level.

For each of these stakeholders, there is of course significant nuance to these priorities. The diversity of perspectives means that communicating success should reflect the intended audiences. For national stakeholders, carbon metrics and alignment with policy goals are critical. For communities, stories of improved quality of life, resilience, and empowerment will resonate more strongly. Tracking and reporting indicators that highlight the wider success of the project – not just emissions – could help maintain momentum, demonstrate progress, and build trust across all levels. Section 7.3 provides additional context to how these metrics could be developed into a monitoring and impact framework, while Appendix C proposes a long-list of potential co-benefit indicators.

Community wealth is a key driver and delivery mechanism

One of the most powerful motivators for action within the CNI project is the creation of community wealth. For many islanders, decarbonisation is not the primary driver – it is often perceived as a secondary goal or even a “side effect” of interventions that meet immediate social and economic needs. Practical and financial benefits are the levers that inspire engagement and behavioural change.

Without a strong social and economic case, interventions risk limited uptake and poor sustainability. It is the successful adoption of measures – such as energy efficiency upgrades, establishing community-owned renewables, and improving reliability of low-carbon transport – that will ultimately deliver carbon reductions. This reflects the earlier finding that indicates what success looks like depends on “for whom”: for communities, co-benefits matter most, and among these, enhancing community wealth and improving island life beyond the abstract lens of carbon metrics is critical.

For CDO’s this insight is equally important. Community wealth is not just a co-benefit – it is a delivery mechanism. Leading with the social and economic case for change, while demonstrating how these actions also reduce emissions, is far more likely to galvanise communities and sustain momentum. In short, framing decarbonisation as a route to stronger, more prosperous communities is essential for success.

Achievability of project goals varies significantly across theme areas

Some pathways offer strong leverage for the project, while others are constrained by systemic factors beyond its control.

Where barriers are primarily within the scope of the CNI project – such as project design, capacity building, and knowledge and data gaps – there is considerable opportunity to accelerate progress. Addressing these barriers through targeted support, and skills development can remove bottlenecks from pathways, in particular for energy efficiency.

Conversely, pathways disrupted by institutional or infrastructural constraints – such as grid capacity limitations, technology development, and policy reform – are naturally more limited. These challenges sit outside the remit of the CNI project and require broader policy interventions, funding structure revisions or significant capital investment at national scale. Understanding where the CNI project has real leverage, and where constraints are systemic, will help the project focus effort where it can deliver the greatest impact. Section 7.1 provides clarity on what this means in reality for the CNI project.

Funding Structures can create uncertainty and inefficiencies

The current annual funding cycle creates contributes to bottlenecks in delivery, particularly for projects that require longer-term planning horizons or sustained investment (such as nature‑based solutions or large‑scale retrofit programmes). This time‑limited funding structure can limit the ability of island authorities and delivery partners to commit to multi‑year workstreams, secure long‑term contracts, or sequence projects efficiently.

This issue lies outside the direct boundary of the CNI project and that there is limited flexibility within the CNI capital fund to alter the current funding structure, given national budgeting processes. However, this is as an important finding for future consideration. In light of these constraints, it is likely that islands will need to explore and leverage alternative funding mechanisms that do offer multi‑year settlements to support projects that require sustained investment.

Recommendations

Our reflections from this project point to a widening of how success could be defined and delivered. Carbon neutrality remains the ultimate goal but achieving it depends on enhancing the use of co-benefits within the project from a delivery mechanism and consideration within the CNI capital fund projects, to a more prominent and publicised project goal.

At the same time, success will rely on creating momentum across the islands through active guidance, shared learning, and coordinated support. By stepping into a stronger leadership role, the CNI project can help communities move from planning to action, connect efforts across islands, and enable projects to scale in ways that deliver meaningful benefits for people and place.

If the project scales beyond the initial pilot phase of six islands, there are some important considerations that should be made to ensure knowledge and experience is shared widely. A potential programme of work and guide for future islands based on the experience of the six islands to date could be developed.

The Scottish Government and the CNI project could consider:

1. Including co-benefit metrics to highlight wider project success

While carbon neutrality should remain the headline target, the CNI project could also incorporate co-benefit tracking metrics to demonstrate what success looks like in practice and capture the broader positive impacts for communities.

Important note: It is important to clearly state that delivering decarbonisation and achieving emissions reductions remains the primary headline goal of the CNI project, in line with the Scottish Government’s statutory commitment to carbon neutrality by 2045. The intention of highlighting and tracking co‑benefits is not to replace, dilute, or divert attention from emissions‑reduction monitoring. Rather, the inclusion of co‑benefits is intended to supplement and strengthen the delivery of the CNI project by recognising the wider social, economic, and resilience outcomes that arise from decarbonisation activities and already sit under the umbrella of the project. These co‑benefits are inherent to CNI delivery, are already considered through mechanisms such as the CNI Capital Fund application and support sustained community engagement and long‑term carbon reduction outcomes. Tracking co‑benefits alongside emissions reductions is therefore presented as an enabling approach that reinforces, rather than replaces, the project’s core decarbonisation objectives. These metrics will:

• Showcase the wider success of projects beyond carbon reduction, such as improvements in community resilience, economic benefits, biodiversity gains, and social well-being.
• Provide a clearer narrative of the project’s widescale impact for stakeholders and funders, strengthening the case for continued investment.
• Enable better decision-making by highlighting which projects deliver the greatest overall value.
• Please refer to Appendix C for the suggested co-benefit metrics and point 6 below for further elaboration.

1. Enhance coordination and visibility of existing technical knowledge learning functions

The CNI project could benefit from expanding the coordination, visibility, and accessibility of existing technical knowledge and learning functions already provided, for example, via partners such as Scottish Futures Trust (SFT) and Community Energy Scotland. This is not intended to create a new centralised role or duplicate existing provision, but rather to ensure that communities can more easily access, apply, and share relevant technical guidance as they move from CCAPs into implementation.

This could include:

• Clearer signposting and consolidation of existing technical support offers available to island communities.
• More systematic sharing of lessons learned (both successes and challenges) across islands to reduce duplication and accelerate delivery.
• Light‑touch coordination between existing providers to ensure guidance reflects island‑specific contexts and constraints.
• Enhancing the current CNI website or platform to move beyond document storage towards a more structured, searchable knowledge and learning resource.

1. Programming support

Communities face challenges in ensuring measures are viable and scalable. The CNI project can play a strategic programming role by:

• Taking a high-level, centralised view to develop programmes of work across themes (energy efficiency, solar installation, EV charging, education, training, etc.).
• Grouping projects across an intra- and inter-island scale to create larger-scale programmes, reducing costs, improving contractor engagement, and fostering collaboration.
• Preparing implementation‑ready packages for when funding becomes available, ensuring projects can move quickly from planning to delivery. Stakeholders noted that pipeline‑type activity is already underway through existing CNI funding and project development processes. However, there are no examples yet of pilot projects from one island being integrated into a work plan for other islands, so a more explicit programmatic framing could help make this activity more visible and effective in supporting communities to move from planning to implementation.
• Aligning CCAP priorities with timelines and current applications to identify opportunities for joint programming.

This approach will help islands progress from planning to action and strengthen the overall impact of the CNI project. A programmatic approach will be beneficial in a number of ways:

• Capacity building across the islands can be aligned
• Procurement might potentially be simplified
• Knowledge sharing is more appropriate
• Tracking progress could be easier

1. Piloting and knowledge capture

Piloting is already a strong feature of the CNI project, but its value can be enhanced through:

• A formalised, standardised process for documenting lessons learned from pilots, covering:
  • Idea development
  • Grant application framing
  • Stakeholder involvement
  • Setup and management
  • Monitoring and data capture
• Results, strengths, and weaknesses
• Idea development
• Grant application framing
• Stakeholder involvement
• Setup and management
• Monitoring and data capture
• Results, strengths, and weaknesses
• Regular forums and central storage of pilot learnings and data that is accessible to islands to enable them to learn from each other and replicate successful approaches.
• This will ensure pilots contribute to long-term knowledge and scalability and establishes institutional knowledge that is protected from staff-turnover.

1. Using the ToC framework for project and policy design

The nine ToC outcome pathways developed as part of this project could also be used going forward. Maintaining the ToCs as live frameworks means they can be utilised as an ongoing project planning tool and mechanism for prioritisation, problem-solving, and adaptive delivery.

Key actions to take forward:

• Review the identified universal barriers within CNI’s scope and develop plans to address them, assessing the feasibility of proposed solutions, and prioritising these with delivery partners for future phases of the project.
• Use the desired outcomes to inform activity design, working with CDOs to brainstorm which activities are most likely to deliver these outcomes and prioritising based on urgency, feasibility, and strategic impact.
• Embed adaptive delivery practices, using the ToC as a long-term reference point for recalibrating priorities as geopolitical, technological, and social contexts evolve – regular stock takes can inform how defining success may change in the future. 
• Integrate the ToC into project reviews, ensuring that policy updates and funding decisions are guided by the pathways and assumptions mapped in the framework.

1. Developing a monitoring and impact framework

Reflecting the recommendation to consider tracking broader co-benefit success metrics, we suggest an approach for developing a monitoring and impact framework for the CNI project. We created a long list of potential indicators that reflect the outcomes identified in the ToC outcome pathways. These suggestions are intended to be a starting point for dialogue, rather than a prescriptive set of requirements. The full list of proposed indicators is provided in Appendix C.

The indicator list was developed considering both the aspirational nature of the project and the practicalities of data collection. Importantly, there is no expectation that most of these metrics will be adopted in full. Instead, this work identifies potential options for measuring wider project success, recognising that what is implemented will depend on project capacity and other contextual factors.

The list is intended to act as a menu of options that can help track progress and impact over time. The aim is to spark conversations with Scottish Government and CDOs about what is feasible, what is ambitious, and how to agree a shared framework that secures buy‑in from all partners.

For each of the nine outcome pathways indicators have been suggested across three time horizons (up to 2030, up to 2035, and up to 2040). For each indicator, possible data sources and approaches that could support tracking have been highlighted, as well as providing a high-level RAG rating. It is recognised there may be additional datasets available that are not publicly available, or there may be constraints in accessing some datasets The RAG rating indicates which indicators are more straightforward to implement, which may require additional effort or coordination, and which are more aspirational and would need further work or support for CDOs. Finally, the types of support that might be needed to help CDOs and other tracking bodies take these indicators forward has been suggested. The full list of indicators is provided in Appendix C.

The next steps for developing this framework would involve working collaboratively with CDOs to refine and prioritise the proposed indicators. Suggested steps include:

1. Review and validate the long-list indicators with CDOs: Engage with CDOs to review the proposed indicators, discuss ambition and capacity, and co-create a roadmap for integrating these metrics into CDO and CNI reporting processes.
2. Conduct a data audit and indicator alignment: Investigate further what data is already collected across islands and identify opportunities to align indicators with existing datasets or adapt indicators to fit available data.
3. Assess contextual relevance for each island: Determine which indicators are most relevant for each island. For example, CDO feedback suggests existing data on energy efficiency and fuel poverty is collected by some islands – indicators relating to these themes could be prioritised on certain islands where applicable.
4. Develop standardised methodologies: Explore options for standardising data collection across islands to enable consistent tracking. Islands with advanced capacity in certain themes or methods could act as demonstrators/pilots, providing lessons learned for others. If the indicators are to track success, then consistency across islands will be important.
5. Consider and formalise frequencies and responsibilities: Agree on reporting frequency, balancing effort and data quality. For example, indicators requiring community surveys might be collected bi-annually or grouped in theme to reduce fatigue. Equally, it is important to agree and formalise responsibilities for collection.
6. Establish agreed monitoring frameworks for the CNI project and each island: Incorporating these activities, develop a formal, co-developed and agreed CNI monitoring framework for the CNI islands.
   1. Provide capacity building and support: Support CDOs with training on data collection and categorisation; development of templates for data entry; guidance on data proxies and calculation techniques (e.g., carbon savings modelling).
7. Longer-term – explore a CNI data dashboard: For centralised tracking and demonstration of success. This could include island-specific pages and a public viewing area. It could be a logical extension to the existing Scottish Islands Data Dashboard.

Conclusion

The CNI project has already delivered a strong and measurable legacy for the islands involved, demonstrating successful community‑led climate action. Through carbon audits, CCAPs, community engagement, knowledge exchange, and the development of finance roadmaps, the project has laid solid foundations for long‑term decarbonisation. This groundwork has translated into tangible progress across transport, energy, food systems, biodiversity, and climate resilience. These achievements have strengthened local capacity, enhanced community wealth, and created a model that is already being replicated across Scotland’s islands.

Building on this success, there is significant potential for the next phase of the CNI project to deliver even greater impact. The project is uniquely placed to help define and demonstrate the next stage of successful island decarbonisation and community resilience. This includes widening the scope of what is tracked and communicated – elevating co‑benefits alongside carbon outcomes – to better showcase the full value of the project and inspire other communities. Developing a wider indicator framework in partnership with communities and CDOs, and upskilling them in its use, would align closely with the CNI remit and help embed long‑term capability.

The CNI project already provides tailored support, knowledge sharing, and coordination across islands, and there is an opportunity – where appropriate – to deepen this role. More guidance on delivery, stronger programming support across islands, and enhanced facilitation of data capture and learning could accelerate progress and improve replicability. Likewise, the CNI project is well placed to work with communities and national stakeholders to identify and mitigate against systemic barriers to implementation.

Overall, the project has established a strong foundation of capacity, community ownership, and practical delivery. With continued investment and a strengthened leadership role, the CNI project can build on its existing achievements to drive deeper decarbonisation, expand the definition of success to uplift co-benefits as key goals for the project, and ensure that island communities across Scotland – and beyond – can learn from and build on this work.

References

Carbon Neutral Islands (no date) Carbon Audit. Available at: https://cni.scot/process-of-cni/carbon-audit/ (Accessed: 1 August 2025).

Carbon Neutral Islands (no date) Community Climate Action Plans (CCAPs). Available at: https://cni.scot/process-of-cni/climate-action-plans-ccaps/ (Accessed: 1 August 2025).

Scottish Government (2025) Carbon Neutral Islands Financing Roadmap 2025–2028. Available at: https://www.gov.scot/binaries/content/documents/govscot/publications/advice-and-guidance/2025/05/carbon-neutral-islands-financing-roadmap/documents/carbon-neutral-islands-financing-roadmap-2025-2028/carbon-neutral-islands-financing-roadmap-2025-2028/govscot%3Adocument/carbon-neutral-islands-financing-roadmap-2025-2028.pdf (Accessed: 7 August 2025).

Scott Watson (2023) Cumbrae Community Climate Action Plan. Available at https://communityenergy.scot/wp-content/uploads/2023/06/Website-Cumbrae-CCAP-Final-compressed.pdf (Accessed: 1 December 2025).

Scottish Government (2024) Carbon Neutral Islands Project Progress Report 2023–2024. Edinburgh: Scottish Government. Available at: https://cni.scot/wp-content/uploads/2025/03/carbon-neutral-islands-project-progress-report-2023-2024.pdf (Accessed: 1 August 2025).

Appendices

Appendix A Methodology

The methodology comprised four key steps: (1) desk-based research and the development of a draft ToC, (2) stakeholder engagement and validation, (3) finalisation of ToC and report development, and (4) development of case studies.

1. Desk-Based Research

The desk-based research provided the foundation for developing the draft ToC and answering the research questions. This stage involved a comprehensive review of 35 documents published by the CNI initiative and its partners, supplemented by relevant academic and grey literature. The reviewed materials included progress reports, CCAPs, carbon audits, feasibility studies, technical assessments, and policy case studies. A full list of documents is presented in Table 4.

Table 4: Outlining the full list of documents reviewed under the desk-based research.

The evidence gathered through this review enabled us to document CNI’s activities, progress to date, and established a clear picture of the project’s current position and its pathways toward achieving climate neutrality. This evidence informed the development of an initial ToC diagram, mapping pathways from activities to short-, medium- and long-term outcomes.

1. Stakeholder Engagement and Validation

Seventeen 1-hour structured interviews were conducted with representatives from national organisations, local authorities, and CDOs across the six islands as shown in Table 5.

Table 5: Stakeholders interviewed

These interviews provided critical insights on validating the draft ToC, including its logic and the nine CNI outcome pathways including: the activities and outcomes; systemic barriers and enablers to achieving carbon neutrality; and data availability for monitoring indicators. Stakeholders reviewed and refined the ToC collaboratively using an interactive Mural whiteboard, ensuring it reflected community priorities and realities. Thematic analysis of the qualitative data revealed common patterns and island-specific variations, which were instrumental in refining the ToC and ensuring the outcome pathways are achievable and context-specific.

1. Finalising the ToC and Report Development

Step 3 of the project synthesised evidence from the desk-based review and stakeholder engagement to refine the ToC and draft report. To validate the findings further and strengthen the recommendations, interim findings and initial recommendations were presented to the Scottish Government Steering Group and ClimateXChange (CXC). This session tested the framing of the analysis and recommendations against national priorities, ensuring alignment with policy objectives and strategic thinking. Additionally, a separate presentation was held for the CDOs to confirm the interpretation of the interview insights and proposed recommendations aligned with local priorities and needs.

These validation sessions were critical in embedding both Scottish Government perspectives and community priorities within the final report. Feedback from these sessions informed refinements to the ToC, clarified CNI outcome pathways, provided clear answers to the research questions and the selection of proposed indicators for tracking progress under the CNI project.

1. Development of Case Studies

To illustrate the CNI’s project achievements and impact, the final report includes five case studies, for islands participating CNI initiative. These case studies showcase examples of successful decarbonisation actions or meaningful progress supported by the CNI project. Each case study was selected based on its relevance and ability to demonstrate a unique or complex challenge that had been effectively addressed, approved by Scottish Government. The case studies drew on multiple sources, including:

• Publicly available data and documentation
• Findings from the desk-based research and stakeholder interviews with CDOs
• Information and data requests to CDOs via email
• Each case study has been reviewed and approved by the relevant CDO.

By highlighting practical examples of progress, the case studies demonstrated how the CNI project enabled communities to overcome systemic barriers and advance toward carbon neutrality. They also provided transferable lessons for other island and remote community contexts. The full case studies can be found in Appendix D.

1. Limitations

While the methodology adopted for this project was robust and fit for purpose, there are some limitations that should be acknowledged:

Scope of stakeholder engagement

The project timeline and scope did not allow for direct engagement with community residents. Interviews were limited to CDOs, local authorities, and national organisations. Although direct community input was not possible under this project, the inclusion of CDOs who act as trusted intermediaries and represent local voices helped ensure that island perspectives were reflected in the findings. Follow-up presentations to CDOs further validated the interpretation of community priorities.

Focus on existing documentation.

The desk-based review relied on existing project literature and publicly available data. While this provided a strong evidence base, it may not fully capture emerging activities or informal community initiatives that are not documented. To combat this the interviews with CDOs, anchor organisations and Scottish Futures Trust for example allowed us to (1) validate the desk-based research to understand if this is up-to-date and (2) understand if any new information is relevant or new advancements.

Data availability and consistency.

The availability and quality of data varied across islands. Some technical assessments and carbon audits were more comprehensive than others, which introduced challenges in benchmarking outcomes and defining indicators consistently across all islands.

Appendix B CNI Theory of Change

A Theory of Change framework was developed across each theme. The following pages show the resulting diagrammatic representation of the framework.

Table 6: Outcome areas and barriers

Theme Area 1 – Energy Efficiency

Energy efficiency (EE) is identified as a cornerstone activity of the CNI project having been consistently highlighted across the islands as a high priority area for delivering on both decarbonisation targets and immediate, tangible community benefits.

Figure 2: Theme area 1 – Energy Efficiency ToC diagram.

Cited Barriers to Implementation

Achieving medium- and long-term outcomes, such as increased uptake of retrofits leading to reduced fuel poverty and greenhouse gas emissions is constrained by two main factors: funding accessibility and technical capacity.

“Accessing grants is often complicated”, leading “some householders to abandon applications”. Short-term annual funding cycles are viewed as “frustrating and a distraction from achieving longer-term”, capital-intensive investments. Funding caps also exclude middle-income households who do not qualify for support yet cannot afford high upfront costs.

There is a shortage of accredited contractors across the islands. As a result, obtaining reports, such as Energy Performance Certificates (EPCs) which is needed to access some types of grant funding, is challenging and creates a backlog of projects. Where islands do have local contractors, they often lack the accreditations required by grant funding to be eligible for a contract to complete installations. Consequently, grant funded installations tend to favour larger mainland companies. This limits opportunities for local delivery and undermines efforts to build island-based supply chains.

While the barriers identified for this pathway are significant, most fall within the influence of the CNI project, meaning there is considerable scope to address them and achieve meaningful impact. There are also positive examples to build on, such as retrofit trials on Raasay and PV-battery installations on Cumbrae (see Case study: Millport buildings solar PV and battery installations in Case Studies).

Primary Co-Benefits and Considerations

• Lowering household energy bills and reducing fuel poverty.
• Warmer homes.
• Improved health outcomes.
• Energy resilience

Theme Area 2 – Renewables

Figure 3: Theme Area 2 – Community Owned Renewables ToC diagram.

The renewables theme as outlined in Figure 3 is focused on installing assets such as rooftop solar, wind turbines, and battery storage to create local low-carbon energy generation capacity. However, given that the evolution of the UK electricity grid is already setting it up to achieve net zero by 2030, it should be noted that the main purpose of this theme is to provide low-carbon energy resilience while providing a source of financial income to benefit the community against a context of rising energy and electricity bills. Island context varies across the islands. For example, Cumbrae has shifted from large-scale solar farm proposals to decentralised rooftop solar, which has proven effective in increasing visibility and engagement. Barra is prioritising installations on community facilities to reduce operating costs, while Hoy in Orkney has successfully integrated solar and battery systems alongside existing community wind turbines, using revenue to fund services such as free transport. Raasay benefits from the precedent set by its community hydro scheme but faces grid capacity constraints, and Islay continues to leverage council-supported assets, recognising the strong benefits of community ownership.

Cited Barriers to Implementation

As shown in Figure 3, securing grid connections for community-scale projects is a major constraint, with islands facing long waits for upgrades and uncertainty over connection guarantees. This is a national issue across the UK.

Similar to theme area 1 – energy efficiency, a key barrier is the lack of local skills. While CNI aims to support local upskilling, the absence of local accredited contractors along with the local authority’s public procurement requirements means projects often rely on external providers, which increases costs and introduces logistical challenges such as ferry travel for maintenance. As a result, there are limited opportunities for local delivery undermining efforts to build island-based supply chains.

Primary Co-Benefits and Considerations

• Community wealth building:
  • The financial savings made from reducing the consumption of imported electricity and the revenue generated from selling when generation exceeds local demand generates financial wealth that can be re-invested in the local community. This strengthens economic resilience and supports wider community priorities.
• Energy resilience:
  • Generation assets paired with battery storage creates systems that are “island mode capable”, providing backup power during outages and improving security. This particularly valuable for communities at risk of facing frequent disruptions to their electricity supply.
• Education and behaviour change:
  • The visibility of community-owned renewables increases local curiosity and interest in decarbonisation measures, increasing awareness and trust to support the uptake of these solutions.

Theme Area 3 – Low-Carbon Transport

The Low Carbon Transport ToC as outlined in Figure 4 aims to reduce carbon emissions from transport through three strategies: expanding EV infrastructure, promoting active travel, and electrifying communal fleets. While vital for decarbonisation, this theme faces challenges such as cross-boundary emissions, reliance on external infrastructure, high upfront costs, and cultural barriers.

Although the ultimate goal is reducing emissions, local priorities often focus on improving access, lowering travel costs, and enhancing active travel. These priorities reflect the practical realities of island life and what is within control of the community, for example, Cumbrae offers bike-sharing schemes, whereas there are currently no actions being taken to decarbonise the ferries islands rely on as they remain outside local control. Hoy in Orkney illustrates success, with the electrification of its community transport service funded by the CNI capital fund (see Case study: Community transport electrification).

Figure 4: Theme Area 3 – Low-carbon Transport ToC diagram.

Cited Barriers to Implementation

A significant challenge, as illustrated in Figure 5, is the high upfront cost of electric vehicles. In addition, residents are also deterred because of a lack of charging infrastructure both on-island and off-island (which is the case for Barra and Vatersay). The installation of charging infrastructure can also be delayed due to grid constraints.

Beyond EV adoption, while improvements to walking and cycling paths are welcomed, they do not always lead to a reduction in car use, particularly for commuting. This is not helped by an existing cultural preference for private cars over communal transport options, such as minibuses.

Finally, for most islands, ferries and aviation account for the largest share of transport-related emissions, yet these remain outside local control. This creates an ‘evidence ceiling’ for decarbonisation efforts, as progress within the islands cannot fully offset the impact of external travel.

Primary Co-Benefits and Considerations

• Improved mobility and access as the electrification of community transport services is expected to both improve reliability and coverage of transport to residents in the case of Hoy.
• Improved health and wellbeing from increased active travel.
• Using or switching completely to EVs reduces the burden of fuel and vehicle maintenance costs for residents.
• Community wealth building from the revenue that can be generated provision of electrified transport like e-bike sharing schemes for both residents and visitors alike.

Theme Area 4 – Nature-based Solutions

The Nature-based Solutions (NbS) ToC as outlined in Figure 5 offers long-term carbon storage and climate resilience. While carbon reduction is the ultimate goal of the CNI Project, NbS is critical for addressing the ecological crisis alongside the carbon challenge. However, NbS delivers low immediate community benefit and carries high implementation risk. Hence, the role of co-benefits is critical for this pathway as this provide more tangible and immediate reasons for communities to enable and support these activities over carbon sequestration which is typically viewed as more abstract and long-term.

Figure 5: Theme area 4 – Nature-based Solutions ToC diagram.

Figure 5 illustrates the NbS pathway, showing activities, outcomes, and barriers. Structural and financial constraints dominate this pathway. The CNI project can play a catalytic role in building local delivery capacity however it cannot directly resolve systemic policy issues such as crofting regulations or land ownership and securing long-term funding.

Cited Barriers to Implementation

Securing agreements with landowners and crofters remains one of the most significant challenges that has spanned generations due to long-standing mistrust and cultural norms, in addition to policy constraints such as the crofting system and unmapped peat cutting rights. These structural issues create uncertainty and “slow progress on restoration activities”.

Another critical barrier is the lack of demonstrator projects, without visible examples of practical and financial benefits, buy-in to shift land management practices is limited.

Gaps in local data and capacity also hinder delivery. Many islands rely on national datasets that lack local specificity, and limited technical expertise means strategic audits often fail to translate into actionable plans. These gaps create uncertainty around the best restoration approaches and slow implementation. Quantifying emissions savings from NbS, such as invasive species removal, is difficult and requires a long-term approach to monitoring and measurement, which in turn makes securing funding (particularly short-term) challenging.

Primary Co-Benefits and Considerations

• Improved ecosystem health and biodiversity.
• Projects that enhance natural surroundings and involve iconic species (e.g., red squirrel reintroduction on islands like Cumbrae) can also boost local pride and attract tourism.
• Restored habitats provide resilience to climate risks, such as flood management on islands.
• Knowledge sharing embedded as part of projects can also support education around the potential and role of NbS.
• Community wealth building through the generation of local employment for tasks such as invasive species removal, as seen in Raasay (see Case study: Invasive Species (Rhododendron) Removal).
• Local community capacity building through training local contractors and volunteers for tasks, such as invasive species removal, as seen in Raasay (see Case study: Invasive Species (Rhododendron) Removal).

Theme Area 5 – Circular economy

The Circular Economy (CE) ToC as outlined in Figure 6, aims to shift island communities from a linear consumption model to one focused on resource efficiency, reuse, and waste reduction. These practices align strongly with the “make do and mend” culture that has long characterised island life, making CE highly relevant. However, implementation faces logistical and infrastructure challenges, many controlled by external bodies. Impact varies by island, influenced by proximity to the mainland and local waste systems. For example, Cumbrae’s emissions from waste are naturally low due to its closeness to the mainland, yet there remains strong interest in reuse initiatives. In contrast, Islay faces significant waste-related challenges, with landfill reduction and improved recycling identified as priorities for the wider council. Hoy struggles with storage capacity for waste awaiting transport off-island, while Shetland’s recycling infrastructure is constrained by the cost of sending materials to the mainland.

Figure 6: Theme area 5 – Circular Economy ToC diagram

Cited Barriers to Implementation

The main limitations arise from infrastructure gaps and the high cost of transporting and treating waste, which lie largely outside the CNI project’s control. Waste management, covering collection, disposal, and recycling, is governed by local authorities and constrained by logistics. These systems often require waste to be shipped to the mainland, creating prohibitive costs. For bulky items such as old vehicles, removal expenses frequently lead to abandonment or illegal disposal. A lack of local infrastructure and storage capacity for goods awaiting shipment further hampers recycling, even among motivated residents. The cost of moving waste off-island often makes recycling financially unviable compared to less sustainable practices. While these systemic barriers cannot be resolved by CNI, they shape the context for local action. Remaining barriers that can be addressed relate to capacity and engagement. Although awareness of waste reduction is high, knowledge of what can actually be recycled within council systems is still limited.

Primary Co-Benefits and Considerations

• Behavioural change by prompting residents to think differently about consumption and waste.
• Community cohesion and resilience:
  • Repair cafés and reuse hubs not only reduce waste but also strengthen social capital by bringing people together around shared values of resourcefulness and sustainability.

Theme Area 6 – Low-Carbon Food Supply

The Low Carbon Food Supply ToC as outlined in Figure 7 focuses on strengthening local food production, reducing reliance on imports, and improving food security through community-led initiatives and partnerships. Although its direct impact on greenhouse gas emissions is limited, it supports the building of a level of food security and community resilience. The importance of this varies by island. Barra faces severe food shortages during ferry delays, while Hoy, its short growing season and limited capacity for high-protein feed renders food growing a hobby rather than a significant contributor to food security.

Figure 7: Theme Area 6 – Low Carbon Food Supply Chains ToC diagram.

Cited Barriers to Implementation

The shift towards greater local food production faces economic, logistical, and environmental constraints. Limited access to land is a barrier, as plots are often controlled by “large or absentee landowners reluctant to support management changes”. This reliance on landowner cooperation restricts the scalability of community-led projects. Logistical and regulatory hurdles add complexity; in Islay, livestock must be transported to the mainland for slaughter incurring high costs while Raasay struggles with land access due to restrictive crofting.

Economic viability is another challenge, as local food sales rarely succeed without subsidies. Producers struggle to compete with imports supported by established systems favouring larger farms, making sustained production difficult.

Environmental factors, including short growing seasons and limited suitable land, further reinforce the perception of food growing as a hobby rather than a practical solution.

Primary Co-Benefits and Considerations

• Resilience building and food security which is particularly important for island communities which are vulnerable to supply chain disruptions.
• Health and wellbeing may also improve as locally produced food is expected to be of higher quality, reinforcing nutritional benefits and community confidence.
• Community wealth building from initiatives, such as venison processing or scaled-up production creates jobs and income, shifting efforts from subsistence to sustainable local enterprise.

Theme Area 7 – Climate Literacy

The climate literacy ToC pathway as outlined in Figure 8 aims to build awareness of climate challenges and solutions, particularly among young people, to foster long-term behavioural change and stewardship for a carbon neutral future. While its direct impact is hard to measure, it is a critical cross cutting theme for sustained climate action. The CNI project’s role is as an enabler, not a sole driver. It cannot guarantee behavioural change but can create the conditions for success by embedding climate literacy in education, supporting youth leadership, and promoting collaboration between schools, communities, and local authorities.

Figure 8: Theme Area 6 – Climate Literacy ToC diagram.

Cited Barriers to Implementation

A key barrier is the lack of intergenerational engagement. The CNI Project’s current efforts rely heavily on schools, which risks leaving older generations disengaged and perpetuating a generational gap. This disconnect is compounded by the possibility of youth leaving the islands, taking their knowledge with them, while climate scepticism continues to gain traction locally and online.

Another barrier is the gap between knowledge and agency. While young people often demonstrate strong awareness of climate issues, they lack the power to act or influence decision-making. Improved understanding does not automatically lead to participation as structural constraints may be in place limiting their ability to drive change.

Resource limitations also hinder progress. Designing activities that resonate with communities is time-consuming for local development officers and requires dedicated funding to maintain momentum.

Primary Co-Benefits and Considerations

Education and behaviour. By deepening understanding of climate challenges and solutions, it encourages active participation and co-design of initiatives, ensuring that climate actions reflect local priorities and have a higher chance of success. Intergenerational learning is another key benefit. Connecting students with elders to share stories of resilience against past extreme events fosters two-way learning, enhances community cohesion, and informs future resilience planning. This approach builds trust and reinforces cultural continuity while addressing climate risks. A further co-benefit is sustained behavioural change. Early engagement embeds climate-positive behaviours that become second nature for the next generation, securing the islands’ ability to maintain carbon neutral status over the long term.

Theme Area 8 – Collaboration and capacity

The Collaboration and Capacity ToC, as outlined in the Figure 9 underpins the CNI Project’s ability to deliver sustainable outcomes. This thematic area focuses on strengthening local governance, partnerships, and delivery mechanisms to ensure that decarbonisation efforts can continue individually CNI funded initiatives. This pathway is consistently prioritised across all islands due to the universal need for stable, locally driven delivery mechanisms. Island communities often operate within fragile systems, relying on a small pool of residents and the expertise of a few key individuals. Without targeted support, high-cost projects risk stalling under the weight of complex processes and short-term funding cycles. By clarifying council and CDO roles, the project can strengthen institutional capacity. Furthermore, fostering partnerships between councils, trusts, and community organisations to support decentralised delivery using local contractors will help ensure carbon neutrality ambitions are rooted in local ownership.

Figure 9: Theme Area 8 – Collaboration and Capacity ToC diagram.

Across the islands there are barriers related to the relationship between CDOs and local authorities. The CNI project has been designed to be community-led with direct Scottish Government funding, however, some funding such as the CNI Capital Fund requires local authorities to submit the applications, adding layers of bureaucracy that can slow delivery. Council buy-in has also varied, with some authorities providing financial safeguards and mentorship, while others have acted as barriers to progress. CDOs play a critical role as local guides with institutional memory, yet uncertainty over funding routes has created confusion about their remit. In summary, unclear boundaries between council and CDO responsibilities heighten organisational tension, highlighting the need for clearer role definitions.

As mentioned in several of the nine theme areas, short-term funding cycles create financial instability, making CDO roles insecure and recruitment difficult. This stop-start approach erodes institutional memory and pushes decisions toward quick wins rather than long-term decision making.

Primary Co-Benefits and Considerations

• Long-term sustainability of decarbonisation work:
  • Embedding local knowledge and technical skills ensures that infrastructure can be maintained on the islands without reliance on costly external contractors. This reduces logistical challenges and safeguards continuity well beyond the lifespan of the CNI project. Community empowerment is another critical outcome.
• Community resilience:
  • Strengthening locally controlled institutions, such as Development Trusts, enables communities to shape their own future and design solutions that reflect the islands’ unique social and environmental context. This autonomy not only fosters resilience but also reinforces democratic governance.

Theme Area 9 – Data and Knowledge

The Data and Knowledge ToC, as outlined in Figure 10, focuses on establishing reliable measurement frameworks and ensuring data is actively used to inform carbon mitigation efforts. It is a high priority across all islands and a cross-cutting theme area. Without trusted data, project planning lacks evidence and accountability for progress towards carbon neutrality is hindered. A key consideration underpinning this theme is the need to balance the requirement for high-quality, localised data with the significant cost, effort, and resources needed to obtain it. Linked to this, “there is a risk that an overemphasis on data collection or KPI reporting can delay practical action”.

Figure 10: Theme Area 9 – Data and Knowledge ToC diagram.

Cited Barriers to Implementation

As shown in Figure 10, a key barrier is the reliance on national datasets scaled down for local use, which are often inaccurate and lack credibility within island communities. Poor ground-truthing fuels scepticism, particularly among landowners, as highlighted under

Theme Area 4 – Nature-based Solutions. The absence of detailed baseline data prevents communities from identifying which projects will deliver the greatest impact and hinders effective planning. At the same time, while robust data is essential for accountability, “action based on current knowledge is often the immediate priority”, the pursuit of perfect datasets and prolonged data collection can delay practical interventions and risks slowing progress towards carbon neutrality.

Capacity and resource constraints present another challenge. There is an ongoing need for staff and technical expertise to measure greenhouse gas reductions, particularly around land use.

In addition, siloed working and duplication of effort can impede action. Local authorities and island communities risk operating in isolation, with limited data sharing. Valuable datasets collected by other projects, are often not leveraged, leading to inefficiencies and missed opportunities for collaboration.

Primary Co-Benefits and Considerations

• Improvement of community buy-in:
  • Establishing high-quality, localised baseline data fosters community trust in the value of decarbonisation activities.
• Improved engagement and climate literacy:
  • Providing clear and accessible data, with the support of data visualisation tools, such as GIS story maps, supports improved stakeholder understanding, community buy-in and informed decision-making.

Appendix C Longlist of Proposed Indicators

The indicators in this appendix are categorised to reflect their relative ease of collection and likely availability of data. It is important to note that even those marked as more feasible will still present challenges and may not be practical for all projects. For accessibility reasons, indicator feasibility is expressed using both colour coding and a numerical scale. Colours are not used as the sole means of conveying information. Numerical scores (1–3) correspond to high, medium, and low feasibility respectively, as described in the legend below.

Appendix D Case studies

Case study: Invasive Species (Rhododendron) Removal

This project is focusing on restoring habitats, through the removal of invasive species from priority areas, using local contractors to address man-made environmental degradation while supporting community wealth building.

Island: Raasay

Sector: Nature-based solutions

Timeline / Key Milestones

Co-benefits: capacity building that can support future similar work like tree planting, local employment on the island particularly in the winter months (outside of tourist season), biodiversity gain, building a sense of community agency and ownership around land stewardship, showcasing land stewardship to younger generations, community wealth building, land habitat restoration.

Background and Objectives

In 2023, community engagement undertaken in Raasay identified improving the island’s biodiversity and carbon sequestration as a top priority for the island. To address this, consultation identified that the removal of invasive species, specifically rhododendron ponticum, would be an effective action that the island itself could drive. As an island with areas of high ecological value, such as temperate rainforest and endemic species, such as the bank vole (the Raasay vole), Raasay stands to gain significant benefits. In the past, rhododendron had already been identified by Forestry and Land Scotland as a threat but efforts to eradicate it previously had been unsuccessful due to a lack of follow up. This rhododendron removal project aims to improve the island’s biodiversity and carbon sequestration potential while also being aligned with Raasay’s unique local priorities and supporting community wealth building.

Implementation Approach

To conceptualise the project, a review of national literature was completed and a consultation carried out with local experts and land managers, the Woodland Trust and Forestry and Land Scotland. In addition, the island’s rhododendron infestation was mapped using drone and ground mapping.

Following the award of CNI funding in 2025, the rhododendron removal works began. The removal team consisted of 3 contractors which grew to 5 for Summer and Autumn. Overall, 30 people on-island and 15 people off island have been involved so far. Different removal methods have been explored with stem treatment emerging as the most effective. Stem treatment uses drills or hatchets to apply small amounts of herbicide to the plant base. This method is less physically demanding than traditional chainsaw methods so it is also suitable for community implementation. The project also explored chainsaw application of treatment as a removal method and the removal of other invasive species including trial removals of Japanese knotweed. Overall, this project used removal methods that were significantly lower cost and reduced chemical usage compared to methods defined in official guidance, while still being effective. Ongoing reviews and on-site training have refined the methods used.

As part of this project, chemical handling training was offered to the local community and taken up by 6 people.

This project procured a Utility Terrain Vehicle (UTV) and supported associated training. This vehicle is now also being used to deliver wood for the community owned and operated wood fuel group which delivers sustainable biomass fuel to residents.

Organisations that have partnered and supported the project include University of Tennessee who shared research on carbon sequestration and biodiversity impacts, the Dulra Project in Ireland who provided informal mentorship and practical advice from their experience in community-based rhododendron eradication, Forestry and Land Scotland, local experts, ecologists, Great Glen Ecology, Tracks Ecology, and the Woodland Trust.

Forestry and Land are a significant landowner in Raasay impacted by Rhododendron infestation. The partnership established with Forestry and Land has been instrumental and is also currently support the continuation of rhododendron removal works beyond that which has been funded by CNI.

Funding and Costs

The project was awarded £75k in 2024-25 capital funding round. CNI funding from previous years was also used to fund the rhododendron mapping to support the application for the 2024-2025 funding round. This project has led to the establishment of a partnership with Forestry and Land Scotland which will be able to support continuation of this work on the island in the future.

Barriers

• Selection of contractors needed to follow the local authority’s procurement processes as per CNICF requirements, which was not suitable given the island’s context. The process required piece‑rate contracts (fee per unit removed), which is predicated on the ability to accurately predict costs of removal, which could not be done due to the island’s highly variable terrain and the lack of detailed local data.
• The 1-year terms of CNI funding means the contractors could not be employed to complete the work for the long-term.
• In community consultation, many community members did not feel “qualified” to express their views on land management unless actively involved.
• Official guidance on rhododendron control could not be followed as it did not reflect the unique challenges of each site, failing to account for factors such as weather conditions, contractor availability, land management practices, land use, and public access.  
• Effective long‑term control required diligent and ongoing monitoring is resource intensive, putting pressure on the operational team.

Enablers

• Early involvement of local and external experts ensured the project was based on sound scientific understanding, gave the project credibility in the community.
• Maintaining autonomy on island allowed dynamic and agile working.
• Opening up training opportunities to allow locals to be involved.
• Informal mentorship from the Dulra project (Irish organisation with experience in rhododendron removal) provided practical advice on running a large‑scale, community‑centred eradication project. 
• Being able to execute a day rate contract with removal contractors rather than a piece-rate contract has resulted in more cost-effective use of funding, enabling the removal works to cover 110% of the scope that would have been completed under a piece contract.
• Adoption of the stem‑treatment method allowed effective removal using limited equipment, making the work achievable at a community level. 
• Employing local contractors resulted in high quality work.
• Working closely and building strong relationships with stakeholders and contractors helped support contractor retention.
• Strong positive feedback from community members reinforced the value of the work and encouraged ongoing participation and support. 
• Collaboration with Tennessee University enabled scientific monitoring of biodiversity differences between infested and non‑infested sites, strengthening the project’s evidence base.

Outcomes, Impact and Lessons Learned

Since January 2025, approximately 140 hectares have been cleared, this is over half the island’s total infested area and 110% of the original expectations of the project. The kill rate is 90% (measured by the total bushes that appear to be effectively treated) with some sites achieving over 95%.

Given the project’s short lifespan so far, it is not yet possible to estimate its greenhouse gas reduction impacts. However, further work with the University of Tennessee may be able to provide methods for emissions estimations in the future. It is expected that this project will produce a biodiversity net gain, however the results to evidence this from the University of Tennessee are still pending.

The project provided economic benefits through local employment to island residents supporting the retention of community wealth, reducing pressure on grazing land and increasing land value through habitat restoration.

The tangible, visible results of this project has created a sense of community agency, ownership and stewardship. This also showcases the possibilities around land stewardship particularly to the younger generations.

Monitoring

The project is being monitored and evaluated through diligent ongoing site monitoring to measure kill rates, record-keeping of treated sites and resources allocated, and a partnership with the University of Tennessee, which is conducting research on the carbon sequestration and biodiversity impacts of rhododendron removal. This research will help quantify the environmental benefits and provide evidence for similar projects elsewhere.

Voices from the community

“It’s really important and will stick it out as long as there’s funding there to do it.” – Removal contractor

“Would love to see this work expand into the roles of community rangers where people are contracted or employed to serve the island’s needs, ecological needs, and whether that’s rooted in invasive species control, tree planting, perhaps creating access routes.” – Community member

Insights and recommendations for replication or scaling

To support the clearing of future sites, Raasay has developed a cost metric based on levels of infestation to determine the cost of clearing sites with greater accuracy. In addition, a scoring tool has been developed for use in the future to prioritise sites according to different factors. For the replication of this project on other islands, it is recommended to:

• Gather advice from organisations like the Community Woodlands Association and other communities doing similar work.
• Ensure the work fits into the island’s wider land management plans.
• Consider stem treatment as it is a very effective and economic method.
• Work with well-regarded local experts and build relationships with key stakeholders to provide the project with confidence and credibility in the community.
• Assess each site strategically considering practical factors unique to the site such as weather, contractor availability, land management, land uses, public access.
• Maintaining records of treated sites and diligent ongoing monitoring is required.
  

  

• Figure 11: Demonstration of Rhododendron Removal Treatment.

Figure 12: Rhododendron Removal Contractors in the field.

Case study: Millport buildings solar PV and battery installations

Installation of solar PV and battery systems on homes in Millport funded by the 2024/2025 and 2025/2026 Carbon Neutral Islands Capital Fund (CNICF) to reduce carbon emissions, tackle fuel poverty and increase energy resilience.

Island: Cumbrae

Sector: Community Renewables

Timeline / Key Milestones: 2024-2026 (currently awarded second year of CNI funding)

Co-benefits: Capacity building in energy efficiency projects, lower household energy bills and addressing fuel poverty, community wealth building, energy resilience, warmer homes and related health improvements.

Background and Objectives

Cumbrae has one of the highest levels of energy consumption per capita amongst CNI islands. This is at least partially attributed to the inefficiency of much of Cumbrae’s housing stock. It is estimated that more than 27% of households in Cumbrae are likely to be in fuel poverty^[1]. Installing solar PV and battery systems enables households to generate electricity at source (behind-the-meter), reducing peak demand, avoiding complex grid agreements, and improving local energy resilience. As well as reducing imports from the mainland-connected grid and displacing fossil fuels where used. This also supports Cumbrae’s wider motivations to build community wealth, achieve warmer homes, lower energy bills, address fuel poverty, improve overall energy resilience.

This project is intentionally designed as a rooftop‑first, distributed energy strategy to align with conservation rules, planning constraints, available grid capacity, and the island’s finite landscape as a tourist‑focused destination – reflecting community priorities and stated objections to large-scale, ground-mounted renewables.

The initiative aims to lower energy bills, achieve warmer homes, reduce fuel poverty, and build community wealth, with decarbonisation delivered as a consequence of meeting those local priorities – rather than as the primary pitch.

Implementation Approach

Each installed domestic system consists of a 8 panel 3.52kW Solar PV system and a 5.1kWh island-mode ready battery storage system. The buildings receiving the systems were generally 1960s homes, almost all electrically heated with storage heaters, and almost all already benefiting from external wall insulation. Maintaining the same system specifications for each install ensured the systems would be permitted to connect to the local electricity network (to allow selling of excess electricity) with minimal cost and delay via the G98 process rather than the G99 process, this was confirmed by the local electricity network company in advance. The choice of rooftop PV was chosen to ensure compliance with conservation rules and planning constraints. It also avoids sparking undue opposition due to known resident objections to large-scale ground mounted renewables. This standardised system approach achieved the best balance of fairness and consistency to each household, while maximising the number of installs achieved for the funding available. So far, CNI funding has enabled the installation of 25 systems across both domestic and community buildings totalling to 109.81kW of additional solar PV capacity.

The Cumbrae CNI CDO led the coordination of the installations funded both by CNI and those funded by other organisations, this stacking of multiple funding routes has enabled the installations to be scaled and delivered reliably. The CDO supported residents, community organisations and the Cunninghame Housing Association to apply for funding they were eligible (CNI, ECO4, Area Based Scheme, Home Energy Scotland grants and loans, and private/self‑funding). The CDO was trained to be able to lead pre-installation activities achieving certificates from institutions in home energy assessment, thermography, heat-loss calculation, thermal performance assessment, and carbon accounting.

In year 1, local North Ayrshire installers already contracted to do Area Based Scheme installs by the Local Authority, were contracted to support with the CNI project funded installations. This ensured the installations could be completed within the funding timeline.

Post install, the CDO provided support to households to help them understand how their system worked, how to maximise the use of battery, and how to navigate SEG registration with their supplier.

Key partners in this project include North Ayrshire Council, Community Energy Scotland for Technical Expertise and Cumbrae Community Council.

Funding and Costs

This project was awarded £136,500 from the 2024/2025 CNICF and an additional £30,000 as a CNI Direct Allocation from the Scottish Government. The CDO also supported further installations beyond those directly funded by CNI to capitalise on the momentum generated by this project, and these were funded privately by residents, ECO4, Area Based Scheme or HES Grants & Loans.

Barriers

Shifting availability and criteria for multiple funding sources caused delay and confusion even causing damage to trust and reputation.

The installer selection had to follow the public procurement process of the lead applicant, the local authority. This led to significant delays, higher costs and project management issues.

Enablers

The local presence, guidance and coordination provided by the CNI CDO meant residents could get answers to their concern, understand more about their home’s energy usage and the systems being installed. Therefore, they felt empowered when it came to making the decision to participate and trust in the process.

Residents were successfully brought on board by focusing the project communications on the benefits relevant to local priorities which were not necessarily decarbonisation. These priorities were community wealth building, warmers homes, lower energy bills, reducing fuel poverty, protection of local environment. Beginning the installations with familiar community buildings to provide a visible demonstration of the benefits also created a ripple effect of building interest and uptake amongst residents.

The installation of the systems was able to maintain momentum as the CDO took a flexible approach with regards to finding funding for each system, as installs were proposed they directed to an appropriate funding source (not necessarily CNI) that they were eligible for at the time as opposed to depending on a single award.

Outcomes, Impact and Lessons Learned

Given a cumulatively solar capacity installed so far of 109.81kW, it is therefore estimated that the systems so far are reducing Cumbrae’s emissions by 24.6 tCO₂ per year.

In addition, it is projected that the total financial saving that households across Cumbrae are gaining from these CNI funded systems as a result of reduced export of grid electricity and payment for exporting excess solar is currently £19,000.

Beyond the systems funded by CNI, the implementation approach taken in this project has created a ripple effect, catalysing general conversations around energy resilience in the community in general, and as a result, driving wider growth in appetite and uptake for solar, retrofit measures and heating upgrades among Cumbrae residents. For example, this has contributed to a 174% increase in air source heat pump installations.

Households have benefitted from improved health outcomes from warmer homes.

Households are now more confident in their ability to access government funding, setting up government funded programmes for success in the future.

This project contributed to local capacity building by enabling the CDO to undergo training and certification on project management, energy assessment, domestic retrofit assessing, traditional building retrofitting, carbon management and reporting, climate literacy and facilitation, thermal imaging, heat loss assessment, climate risk knowledge, and remote drone pilot skills.

The project demonstrates a scalable, rooftop‑first, behind‑the‑meter delivery model for rapid deployment of household‑level renewables and energy efficiency, enabled by an embedded CDO with community trust and time to help residents navigate complex funding processes.

The success of this model and its potential to be replicated and used to benefit other islands and communities has already been recognised beyond Cumbrae; so far it has been awarded:

• Winner, Best Community Project — 2025 Scottish Renewables Green Energy Awards
• Winner, Small Scale (<£250k) Community Project Award — 2024 Scottish Energy Efficiency Awards
• Shortlisted (Top 5 UK) — 2026 Ashden Awards, Local Energy Innovation

Monitoring

Each installed system has a mobile dashboard allowing households to see generation statistics though this is not centralised in a publicly accessible platform. However, real-time access to the generation data of several community building systems is available.

Post install, the CDO maintains informal communications with households to ensure system remains operational, meets the expectations of the household and is delivering as expected by the project. EPCs are conducted and monitored to document improvements to domestic energy efficiency.

The CDO maintains a database of all solar PV installs on the island and oversees carbon accountancy based on DESNZ capacity factors, local annual solar load and in line with GHG Protocol. Once the systems reach a full year of operations, the CDO intends to collate data across the installs.

Voices from the community

“Your role on the ground has been the driving force in delivering this change and pulling multiple funding streams together. It’s great to see this working to benefit an important rural community.” – Steven Easton (Co-Founder Green Home Systems).

“So good Cumbrae is leading the way in solar roof tops for Scottish Islands” – Camille Dressler (Director, Scottish Islands Federation, Vice-chair, ESIN (European Small Islands Federation).

“It took a week to install, and the solar panels were about three days. It wasn’t too disruptive and I’ve already saved hundreds of pounds on my bills.” – Millport resident.

Insights and recommendations for replication or scaling

• Provide an embedded local leader, such as the CNI CDO, to build trust in the community and provide critical technical support and funding navigation support.
• Complete pre-procurement activities in advance, and ideally by a local with understanding of the community to equip residents with the knowledge to make informed decisions.
• Design the project for local criteria, not for a specific funding stream and then adapt the financing to the eligible funding routes at the time.
• Use benefits relevant to local priorities to secure community buy-in, publicly visible demonstrations can support this.
• Build trusted relationships with the installers and secure local control wherever possible to reduce the risk of project management issues, delays and reputational damage.

Figure 13: Residential installation of Solar PV and battery system.

Figure 14: Community building installation of Solar PV and battery system.

Case study: Community transport electrification

Hoy has been awarded funding from the 2025/2026 Carbon Neutral Islands Capital Fund (CNICF) to fully electrify its community transport fleet.

Island: Hoy

Sector: Low-carbon Transport

Timeline / Key Milestones: September 2025-March 2026 with the vehicles delivered to Hoy and chargers installed by January 2026.

Co-benefits: Community wealth building, providing local upskilling and year-round employment, financial savings in transportation costs, improved mobility across the island to support connected and resilient communities.

Background and Objectives

Many of Hoy’s households are located far from essential services, shops, jobs and the ferry. In addition, many islanders are without reliable access to transport, in particular its residents over 65 (36% of population), families, young adults, and low-income households. The current community transport service runs only on diesel vehicles, however, it represents critical infrastructure for the island. Replacing the current community transport fleet diesel vehicles with an electrified equivalent reduces carbon emissions from Hoy’s transport sector while also supporting the island’s objectives of maintaining and building community wealth, wellbeing and resilience.

Implementation Approach

The 2025/2026 CNICF is funding the procurement, installation and associated training for three Toyota Proace Verso 9-seat electric minibuses and one dual-post Alfen Eve Double Pro-Line EV charging station. In March 2025 a community consultation validated the need to maintain provision of the transport service and provided evidence for co-designing changes to improve coverage of the service. Procurement of the vehicles and EV chargers has been undertaken following public procurement processes. However, significant delays have been experienced so far due to unforeseen bureaucratic processes within Orkney Islands Council and this has consumed all planned project buffers. The EV model chosen is used by other community transport groups across the country. Only one company, Green Installations, quoted for the installation of the EV charger, as they were the only contractor able to complete the installation due to the location of Hoy. The charger will be installed at an Island of Hoy Development Trust (IOHDT) owned carpark in the main settlement of Hoy. No specific planning permission needed to be sought for this project.

IOHDT is providing project administrative, management and governance support with monthly project meetings to track the project. Once the project is completed, community feedback will be sought to help shape the future of the electrified transport service.

Key partners in this project include Hoy residents who participated in the community consultations, Orkney islands Council (OIC), Orkney Motors who will provide inspection and servicing and Green Installations.

Funding and Costs

The 2025/2026 CNICF is providing £131,500, to cover the bulk of the upfront costs of this project. Approximately £6000 worth of support will be provided by IOHDT.

To support the operations of the transport service once electrified, the IOHDT will rely on other forms of income:

• Income generated by the 900kW Community Wind Turbine – £38,000 in the last financial year.
• Community Transport Grant Scheme (CTGS)  -up to £20,000 for year 2025/2026.
• Network Support Grant (NSG) – ~£10,000
• Orkney Islands Council (OIC) Bus Tender –  £13,540 in last financial year.
• Service fares – £3627 for April 2024 to March 2025.

Outcomes, Impact and Lessons Learned

By replacing the two existing diesel minibuses with three EV equivalents, IoHDT estimates they will avoid 23 tonnes of CO₂e per year^[2]. Community wealth building through the use of local Orkney contractors for the installation and maintenance, and through IoHDT community ownership of the vehicles and the charger.

The total cost of ownership of the EVs is expected to be lower than the diesel vehicles. Financial savings are anticipated from the reduction in repairs and fuel savings. These reduction in operation costs means the IOHDT can redirect funding to other parts of the community.

This project is expected to immediately improve reliability of the transport service. It will also improve mobility access for residents, strengthening community connectedness, social and economic resilience. The impact of this is significant given 36% of Hoy’s population is over 65 and more likely to experience reduced mobility.

Upon completion of this project, the IoHDT has already committed to making further improvements to the community transport service by rolling out an app-based booking system (funded by Highlands and Islands Transport Partnership). This will improve the service by transitioning to a demand responsive door-to-door service. This service improvement was identified through direct community consultation. Currently, 50% of the island’s households are excluded from the fixed route-based service. The ultimate outcome is for 100% of Hoy’s households to have access to community transport whenever they need it.

Monitoring

The IOHDT plans to report annually on the service capturing trends in use, passenger numbers, service coverage, service responsiveness and avoided CO₂. The project monitoring will be overseen by the current IOHDT member responsible for the transport service, who will be supported by a dedicated IoHDT Board Member. Progress will be reviewed regularly and shared with the board, OIC, and the Carbon Neutral Islands team as required.

The Trust plans to run biannual surveys to get qualitative feedback from passengers and the community. Feedback on the service will be used to help adapt the model and ensure it continues to meet community needs.

Insights or recommendations for replication or scaling

So far, the lessons learned from the implementation of this project are:

• Future projects must incorporate greater contingency for external agency delays and longer manufacturing lead times.
• Local authorities should better communicate their known constraints upfront to inform realistic planning.

The IoHDT intends to produce a “Hoy EV Transport Toolkit” to help the development of community transport models for other islands. This toolkit will detail project development, procurement steps, operational protocols, community engagement, cost breakdowns, and lessons learned.

Case study: Decarbonising community spaces

Barra and Vatersay have been awarded funding from the 2024/2025 and 2025/2026 CNI Capital Fund (CNICF) to deliver a package of renewable energy and energy efficiency improvements for community assets Vatersay Community Hall and Café (VCHC) and Cobhair Bharraigh to support decarbonisation goals while achieving operational financial savings.

Island: Barra & Vatersay

Sector: Energy efficiency

Timeline / Key Milestones:

Co-benefits: Local capacity building and upskilling, financial savings, energy self-sufficiency and resilience.

Background and Objectives

The development of Barra and Vatersay’s CCAP, identified buildings and heating systems to be a major source of local emissions. On Vatersay, the VCHC is a multi-use venue that plays a vital role in supporting community wellbeing and economic activity. However, it’s aging heating system is inefficient and consumes significant amounts of energy and fossil fuels which, given rising energy costs, threaten its long-term future. Similarly, Cobhair Bharraigh, a community hub which provides day care, a support centre and ‘warm space’ during winter time also experiences these challenges. By investing in solar PV, wind generation and battery storage connected to these buildings, significant operational carbon emissions and cost savings can be made. This will also support the island’s energy security and climate resilience which aligns with Just Transition Principles.

Implementation Approach

At Barra, the 2024/2025 CNICF funded the installation of a 9 kW solar PV system, 40.5 kWh Tesla Powerwall 3 battery storage, 11 Dimplex Quantum storage heaters, and upgraded external windows and doors. Voluntary Action Barra & Vatersay (VABV) acted as Lead/Delivery Partner on behalf of the Carbon Neutral Islands programme. The CNI CDO coordinated development, procurement and reporting, while Cobhair Bharraigh supported site access, planning and day-to-day liaison.

The contractor procurement for Cobhair Bharraigh was undertaken by first identifying potential suppliers through the MCS contractor directory (mcscertified.com), focusing on contractors with relevant accreditations and experience in solar PV, battery storage and heating upgrades. An invitation to tender was issued to 15 contractors. By the submission deadline, one full tender was received from Alex Murray Construction Ltd and one quote from CMS Surveyors Limited. All interested contractors were asked to complete a pre-qualification questionnaire and a detailed invitation to tender response covering technical proposals, pricing, experience and approach to working on remote island sites. Following assessment against these criteria, Alex Murray Construction Ltd was appointed as the main contractor.

Throughout the delivery of the Cobhair Bharraigh project, progress was monitored through regular communication with the appointed contractor and agreed milestones. Delivery was tracked against the approved project scope, budget and timeline, with sign-off required at key stages to confirm works were completed to specification. Site visits were undertaken during installation and the final handover to verify that systems were installed and operating as intended.

Capacity building was embedded throughout the Cobhair Bharraigh project, including the involvement of apprentices during delivery. Upon, project completion, a structured handover was completed to ensure Cobhair Bharraigh staff understood how to operate the new heating controls and had a clear, practical understanding of the PV and battery system, and could confidently undertake day-to-day management of the upgraded building.

At Vatersay, the 2025/2026 CNICF is funding the installation of a 9 kW wind turbine, a 24 kW roof-mounted solar PV array, an integrated battery energy storage system, high-retention storage heaters and air conditioning unit with heating functionality. As part of the procurement for an installation contractor, the job is going to be advertised on the Public Contracts Scotland platform this will ensure the procurement reaches a wider and more competitive field of suitably qualified suppliers, which is particularly important as the wind turbine component of this project, is known to have a limited pool of suitable contractors.

Additional key project partners for these projects include Comhairle nan Eilean Siar who oversaw grant conditions and approvals, Business Energy Scotland and Community Energy Scotland who provided technical advice.

Funding and Costs

The 2024/2025 CNICF awarded £127,022 to cover the costs of the 2024-2025 Cobhair Bharraigh project. The 2025/2026 CNICF awarded £249,000 to cover the costs of the work to decarbonise VCHC.

Barriers

Barra Cobhair Bharraigh

• Following the award of funding, a new CNI CDO was appointed so procurement had to be completed within a compressed timeline.
• As a remote island location, there are a limited number of contractors can deliver the project so reduced competition for specialist renewable energy and electrical works.
• The island’s remote environment caused logistical pressures including weather-related disruption and extended lead times for materials and equipment.
• Delivery took place over the summer period, when travel and accommodation demand on Barra is at its highest, increasing costs and limiting contractor flexibility. Careful coordination of material delivery, travel and accommodation arrangements was required to ensure the works would still be completed within budget and timescale.

Vatersay VCHC

• The VCHC project is currently in progress, a damp patch on the roof that potentially indicated a lack of structural integrity had to be investigated in November 2025 before procurement. The project timeline is now a few months delayed from the initial proposed timeline.

Enablers (from the installation at Barra’s Cobhair Bharraigh)

• Clear funding requirements and a defined scope have helped focus decision making and enabled timely progress despite a compressed delivery timeline.
• Early identification of suitable contractors with relevant accreditations and experience working in remote and island contexts supported procurement and installation.
• Effective communication between all stakeholders enabled issues to be resolved quickly as they arose, particularly in relation to logistics.
• Selecting a contractor familiar with island conditions helped minimise disruption and ensured works were delivered to a high standard within the available timeframe.
• The project delivery team were able to draw on knowledge and experience from the CNI network.

Outcomes, Impact and Lessons Learned

As the Cobhair Bharraigh installation was only completed in November 2025, there is not yet sufficient operational data to report measured savings. Assuming, typical solar PV performance in the Outer Hebrides, the project is expected to cut grid electricity use by approximately 5,000–6,000 kWh per year which equates to a carbon reduction of around 1.1–1.35 tonnes per year. A more accurate assessment of carbon reduction will be provided following the first quarter of operation (February 2026). The energy savings for VCHC are expected to equate carbon reduction of 6 tonnes per year.

The reduction in operational costs for Cobhair Bharraigh and VCHC will allow these organisations to redirect funding towards maintenance of the new assets and community programs. This will improve the long-term financial viability of Cobhair Bharraigh’s and VCHC’s provision of essential services as well as improve its capacity to provide more events and activities to support community wellbeing particularly for these islands’ most vulnerable community members. Financial savings of £10,000 per annum for VCHC from reduced energy bills is anticipated.

For both Barra and Vatersay, these building projects incorporated local capacity building in the installation and maintenance of the new renewable energy and electrical heating systems, strengthening the islands’ resilience and local capacity. This is particularly important for the island as adverse weather conditions, especially in winter, can delay access to mainland-based services.

The VCHC will gain enhanced energy security during grid outages, which are common in winter.

Monitoring

For both Cobhair Bharraigh and VCHC, on-site energy monitoring equipment will enable review and reporting on electricity generation, electricity usage and emissions data. The CNI CDO will include this information in operation reports to be produced in February 2026 for Cobhair Bharraigh and July 2026 for VCHC. For VCHC, to monitor emissions reductions, a baseline audit will be completed prior to installation. Impact and success are being measured through a combination of qualitative and quantitative indicators. These include the number and frequency of community events held post-installation at VCHC (particularly when it serves as a designated Warm Space in winter), confirmation of installed capacity and technologies, and expected reductions in energy consumption and carbon emissions based on system design and manufacturer performance data. Operational feedback from building users and staff will also be used to assess improvements in daily management of the building. Where available, energy bills and system monitoring data will be reviewed to understand changes in energy use and costs over time.

Voices from the community

“Can’t believe they managed to get the work done in the specified timescale. Absolutely delighted with everything to date. It will have a huge impact on a small charity with high heating costs.” – Cobhair Bharraigh Site Manager.

Insights or recommendations for replication or scaling.

As the first phase of the Decarbonising Community Buildings programme, Cobhair Bharraigh provided valuable learning for future phases. A key lesson was the importance of understanding how VAT on renewables is applied and passed through depending on the organisation’s legal structure and VAT status.

From VCHC, a learning so far in the project is the importance of early and detailed scoping, particularly around structural requirements.

The VCHC is intended to serve as a demonstration site for renewable technologies, offering practical insights into the viability of solar, wind and battery storage systems in island contexts. The project team will also facilitate operational demonstrations and highlighting the practical benefits of the renewable systems to island stakeholders. Data on this project will be collected to inform future projects on other islands.

The learnings from these projects regarding procurement, logistics and system integration, is now informing the wider Decarbonising Community Spaces programme on Barra and Vatersay and being shared across the Carbon Neutral Islands network.

How to cite this publication:

Shaikh, S; Voke, E; Li, H; Hanbury, K; Morris, S. (2026) ‘Defining success in decarbonising Scotland’s islands through the Carbon Neutral Islands Project’, ClimateXChange. https://doi.org/10.7488/era/7244

© The University of Edinburgh, 2026

Prepared by Ricardo on behalf of ClimateXChange, The University of Edinburgh. All rights reserved.

While every effort is made to ensure the information in this report is accurate as at the date of the report, no legal responsibility is accepted for any errors, omissions or misleading statements. The views expressed represent those of the author(s), and do not necessarily represent those of the host institutions or funders.

This work was supported by the Rural and Environment Science and Analytical Services Division of the Scottish Government (CoE – CXC).

ClimateXChange

Edinburgh Climate Change Institute

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info@climatexchange.org.uk

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If you require the report in an alternative format such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

1. 
   Scott Watson (2023) Cumbrae Community Climate Action Plan. ↑
2. 
   Calculated using the distanced travelled by the diesel minibuses in 2024. ↑

Display photo for this page is by Duncan McNab on Unsplash

The Carbon Neutral Islands project was launched in 2021 to support six Scottish islands — Hoy, Islay, Great Cumbrae, Raasay, Barra and Yell — in achieving carbon neutrality by 2040. This research reviews what the project has achieved so far, explores what is realistically achievable, and considers how progress could be measured and strengthened in future.

The report assesses activity across nine themes – energy efficiency, low-carbon heating, renewables, transport, nature-based solutions, circular economy, climate literacy, collaboration, data and low-carbon food supply. It also identifies barriers to delivery and considers how the project can generate wider community benefits alongside emissions reductions.

Key findings

• The Carbon Neutral Islands project has supported practical climate action across all six islands, including low-carbon mobility, energy efficiency, renewable energy, local food production and climate resilience.
• The project provides a scalable model for island-led climate action, with lessons that can support wider decarbonisation across Scotland’s islands.
• Delivery has taken place across all nine theme areas, reflecting the range of actions needed to support island decarbonisation and resilience.
• Barriers to delivery include high costs, data gaps, limited on-island skills and knowledge gaps, alongside wider structural challenges such as geography, infrastructure capacity, policy frameworks and funding flexibility.
• Community co-benefits are central to the project’s long-term success, helping to build local support for sustained decarbonisation.

Recommendations

The report suggests that the Carbon Neutral Islands project widens how success is defined and delivered, to ensure that knowledge and experience is within the project. It recommends the CNI project:

• includes co-benefit metrics to demonstrate the wider social, environmental and economic value of projects, encouraging long term support from local communities
• improves the coordination, visibility and accessibility of external technical knowledge and learning functions
• develops programmes to support projects move from planning to action, and strengthen overall impact
• pilots approaches to capturing knowledge and lessons learned from projects
• uses a theory of change framework to measure project and policy design
• develops a monitoring and impact framework to measure outcomes and support continuous improvement.

The report concludes that the next phase of the Carbon Neutral Islands project has significant potential to demonstrate a stronger model of community-led island decarbonisation. By tracking emissions reductions and wider community benefits, the project can better show its full value and inspire climate action across Scotland’s islands.

For further information, please read the full report.

If you require the report or annex in an alternative format, such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

Display photo for this page is by Duncan McNab on Unsplash

Research completed December 2025

DOI: https://doi.org/10.7488/era/7268

Executive summary

Our research examines effective approaches for delivering persuasive messages that support protective health behaviours during adverse weather events. We focus on four weather events within Public Health Scotland’s Adverse Weather and Health Plan 2024–27: periods of hot and cold weather, flooding and drought.

We investigate evidence on the effectiveness of public health messages disseminated for adverse weather events, for general and at-risk populations; which communication channels are most effective; and factors that influence the public’s risk perception and health and wellbeing behavioural responses in relation to adverse weather.

This study was delivered in two phases: a Rapid Evidence Review, supplemented by an engagement phase with organisations representing groups at heightened risk from adverse weather in Scotland.

Findings

Effectiveness of public health messages

Evidence on the effectiveness of public health communication disseminated for adverse weather is limited. Few studies directly link communication to health outcomes, with most focusing on intermediate outcomes such as awareness, knowledge, and behaviour change or intentions to act.

Only three international studies provide causal evidence on the effectiveness of communication interventions specifically designed to target vulnerable populations (older adults, people with chronic conditions). All three focus on heat. From these studies, we learned that:

• Public health messages can lead to behaviour change including improvements in health and reduced pressure on health services.
  
• Complementary policy interventions can enhance impact of communications, enabling behaviour change even in the absence of increases in awareness or knowledge of health risks – highlighting that these are not always necessary preconditions for action.
  
• Targeted information can improve health and behaviour, but some sub‑groups may benefit more than others.
  

Four studies examine public responses to general heat-health messaging delivered through campaigns and alerts in ‘real-world’ settings. Across these studies, the relationship between exposure to advice and self-reported behaviour change is not consistent. Hearing public health information is associated with stronger intentions to act for some individuals, but effects can be modest and uneven, or concentrated in particular groups, and some of those most likely in need of protection are less likely to act. Rather than reflecting a simple linear relationship between information and action, this evidence points to a more complex picture in which behavioural responses are shaped by multiple factors that communicators need to consider.

Factors influencing perception and behavioural responses to adverse weather

The majority of studies we found offer insights into the factors shaping how people perceive, interpret, and respond to adverse weather risks. This evidence suggests that behavioural responses emerge from the interaction of multiple influences. Consistent patterns emerge:

• Personal experience of adverse weather can increase receptivity to guidance. Lack of prior experience, particularly relevant for drought in Scotland, weakens risk perception.
  
• Efficacy beliefs: confidence that recommended protective actions are effective (response efficacy) and achievable (self-efficacy) consistently emerge among the strongest predictors of adaptive behaviour. However, practical barriers such as cost, housing conditions, physical capability, and access to resources can constrain people’s ability to act even when they recognise risks.
  
• Emotions can influence protective intentions. Positive associations to warm weather, particularly relevant to heat and drought, can weaken perceptions in the UK context, while fear or concern alone do not necessarily lead to protective action unless people also feel capable of responding effectively.
  
• Socio-demographic and socio-economic factors do not reliably predict how people perceive weather-related health risks or their behavioural responses. Structural factors, including cost, housing conditions, physical capacity, digital access, literacy, and language, influence whether people receive, interpret, and feel able to act on advice.
  
• Social and cultural environments, including prevailing norms, collective narratives about weather, and trusted relationships with messengers, shape how people interpret advice and whether they act on it.
  

Principles for effective messaging

• Make guidance actionable, specific, and directive – people need to believe they are capable of the action and that it will be effective
  
• Ensure ‘message relevance’: people need to see themselves in the message and believe the message is for them. This includes being mindful of how people self-identify and supporting people to personalise the risk.
  
• Consider people’s emotional responses to certain weather events as some e.g. heat and drought can attract positive emotions. However, counteracting these with negative framings is insufficient unless combined with efficacy information.
  
• Communication should be tailored to different audiences, recognising variation in language, literacy, housing conditions, income, geography, and other factors that shape how people access, interpret, and act on information
  
• Clear, inclusive, and accessible language can improve engagement. Visuals, infographics, storytelling, and culturally relevant communication approaches can further support understanding and make messages feel more personally relevant.
  
• Timing relevant to the weather event is important.
  

Effective communication channels

We found no studies that compare which communications channels or messengers are most effective in influencing changes in awareness, knowledge, attitudes or behaviours. 21 studies across heat (12), drought (3) floods (2), and mixed hazards (4) provide evidence on the main channels used to disseminate information, patterns of access and preference, and the relative strengths and limitations in terms of reach and accessibility. Some of the studies provide insights into characteristics and design features of particular channels such as websites and social media. Broad patterns and principles of effective communication channels emerge:

• Traditional channels (broadcast and print media) remain widely used and valued, especially among groups less likely to engage online.
  
• Digital channels, including websites and social media, are important components of adverse-weather communication strategies. Websites are widely used sources of information, while social media platforms are increasingly used to disseminate adverse-weather and health information and may help reach audiences less likely to engage with traditional media, particularly younger groups. However, access, engagement, and audience reach are uneven.
  
• Formal and informal community networks are particularly important for those who may not engage with formal or digital channels. Their effectiveness is underpinned by credibility and trust; amplification and reach; and relevance and personalisation.
  

Cross-cutting principles of effective communication channels

• Diversify channels for maximum reach and exposure.
  
• Design for equity, reflecting differences in preferences and access patterns, which vary by digital connectivity, literacy, language, and cultural context.
  
• Ensure consistency across channels and messengers. When messages differ across sources or channels, they can cause confusion and reduce trust and compliance.
  
• Trust in the source matters.
  

Links to the wider evidence

Our findings align well with the wider evidence based on public health communication and risk perception but deliver important nuance on communicating public health advice in relation to extreme weather events. For example, on the importance of combining appeal to emotions with efficacy cues.

Glossary / Abbreviations

Introduction

Background: the need for this research

Average temperatures in Scotland are rising, and climate change is contributing to more frequent episodes of heat and cold, flooding and drought, all of which have implications for public health and health inequalities (Adaptation Scotland, 2025; Climate Change Committee, 2021; James Hutton Institute, 2023, Sayers et. al, 2023; UK Health Security Agency, 2023, 2024).

Scotland has a comprehensive policy framework to address the health impacts of climate change. The Scottish Government has developed a set of climate resilience policies, including Climate Ready Scotland, the Climate Change Plan, and the Just Transition Plan. The national response to climate risks is coordinated through the Scottish National Adaptation Plan 2024–2029 (SNAP3).

One important deliverable within SNAP3 is the Public Health Scotland (PHS) Adverse Weather and Health Plan 2024–27 (AWHP), published in July 2024 (PHS, 2024). The Plan sets out PHS’s commitment to working with partners to help mitigate, prepare for, and respond to the potential health risks associated with adverse weather, also recognising that these risks fall unequally across the population. The Plan covers the following weather-related hazards, with a significant impact on health: heat, cold, flooding, and drought.

There is a strong evidence base demonstrating that periods of hot or cold weather, flooding and other adverse weather events pose substantial effects on population health and wellbeing (UK Health Security Agency, 2023). As the AWHP highlights, these impacts are wide-ranging and, to a large extent, preventable. Health effects arise through both direct exposure and wider indirect pathways, with consequences that can be immediate or persist over time. They can exacerbate existing health problems and can contribute to illness, disability, or premature death (PHS, 2024).

While exposure to adverse weather can affect anyone, some people may be more affected than others, due to a wide range of factors, including but not limited to, age, underlying health status, geographical location and socioeconomic status.

The AWHP highlights effective communication as an important component of supporting resilience and preparedness, emphasising the need for messages that are inclusive, accessible, and responsive to different needs and circumstances. However, whether and how people adopt health-protective behaviours in response to communications about adverse weather is complex. People’s perceptions of the risks and their behavioural responses are shaped by a wide range of psychological, social, cultural, and structural factors (Spielhofer et al, 2020). Understanding these influences and communicating effectively, with all the complexities in mind, is critical.

Our research examines effective approaches for delivering persuasive messages that support protective health behaviours during adverse weather events, focusing specifically on the four weather events within the AWHP.

Research aims and report structure

The overall purpose of the research is to help support the delivery of the AWHP 2024-27. It aims to establish the most relevant and effective communication approaches to encourage people to engage in protective health behaviours in the context of adverse weather events. This refers to both what is communicated and how it is communicated.

We address three questions:

1. What UK and international evidence currently exists on the effectiveness of public health messages disseminated for adverse weather events, for general and at-risk populations?
   
2. Which communication channels used for adverse weather events (for general and at-risk populations) are most effective and why?
   
3. What factors influence the public’s risk perception and health and wellbeing behavioural responses in relation to adverse weather events?
   

We begin with a summary of evidence on the effectiveness of public health communication (RQ1, Chapter 4), before turning to an examination of the factors shaping risk perception and behaviour (RQ3, Chapter 5). Understanding these factors provides the context to interpret communication effectiveness and informs the implications for communication (Chapter 6). We turn to evidence on communication channels (RQ2, Chapter 7), before situating the findings within the wider evidence on public health and disaster risk communication (Chapter 8) and drawing together overall conclusions and directions for future research (Chapter 9).

Methodology

The research involved two interlinked phases. In Phase 1 we carried out a desk-based literature review, implemented as a Rapid Evidence Review (RER). In Phase 2 we conducted a series of interactive workshops and interviews with organisations representing at risk groups, to further explore people’s responses to adverse weather health messaging. The design and implementation of both phases were developed in consultation with the project’s Steering Group and agreed at key decision points throughout.

Full methodological details are in Appendix A. Some related issues are outside the scope of this research. These are set out in Section 12.4.

RER findings and nature of the evidence base

Weather event and geographic coverage

We included 32 studies (26 peer-reviewed articles and 6 grey literature items). Most focussed on heat (n = 20). A comparatively smaller number addressed drought (n = 4), floods (n = 2), cold and heat (n=2) and multiple hazards (n = 4). The latter included floods and, to a lesser degree, heat (alongside other extreme weather events that were out of scope). Cold weather as a standalone weather event was not represented. Nine studies were UK-based, alongside those from the USA (n = 5), Canada (n = 4), and Australia (n = 2). The evidence reviews in the sample (11) drew on a wider international evidence base, encompassing countries within the target range as well as others in Asia, and South America. Most studies addressed more than one research question.

The heat literature is the highest in volume and the most varied. Heat is also the weather event with the strongest evidence of effectiveness. The following table provides an overall summary of the studies included in this RER.

Limitations of the evidence base

The evidence base linking adverse weather messaging to behaviour or health outcomes (RQ1) is limited. Where it does exist, it is concentrated in the heat literature. No studies test the effectiveness of different channels. This means that RQ2 on the effectiveness of communication channels is the least well-evidenced. By contrast, the literature on all four weather events provides stronger insight into the mechanisms that shape communication outcomes (RQ3). This includes evidence on how people perceive and interpret risk, what influences protective behaviour, the barriers that constrain action, and the factors that affect whether communication is acted upon. Overall, the evidence base is therefore stronger in explaining the conditions under which communication is more or less likely to succeed than in identifying which specific messages or channels are most effective.

Some studies fall outside a public health frame. For instance, flooding has been extensively examined in the risk and emergency response literature, focusing on property protection, evacuation, and early warning systems, rather than on public health behaviours such as coping with psychological distress. Similarly, some of the heat literature focuses more broadly on weather warnings and risk communication than specifically on public health messaging, and evidence on drought mainly addresses water conservation rather than wider health-focused messaging. Insights from these studies are applicable to our research, but demonstrate the limited research available on broader public health messaging. Much of the available evidence focuses on the response and preparedness phase of the disaster management cycle, with limited attention to the recovery phase or to how communication can support longer-term behaviours and resilience.

Experimental studies used in our review cite limitations related to generalisability, such as limited randomisation, dropout rates, study timing, or response accuracy (e.g., self-reported changes in health). Broader empirical research also faces sampling limitations, including uneven geographic coverage, potential exclusion of some groups, and non-representative samples, all of which affect generalisability. Reliance on self-reported changes in behaviour and retrospective recall may further reduce accuracy in these studies.

Limitations of our approach

While the RER approach balances rigour and efficiency, it is more limited in scope than a full systematic review. Selection decisions considered both the quality of evidence and its relevance to the Scottish context. Non-English-language literature was excluded. Therefore, relevant international evidence may not have been captured.

Our search included grey literature, but we prioritised sources that evaluated communication activity, were explicitly evidence-based or where they supplemented limited peer-reviewed evidence (e.g. drought). Some practice-based insights may be missed.

Phase 2 balanced breadth of insight with the constraints of a time-limited study. It included engagement with national and local organisations, and two place-based community workshops. While these provided valuable lived-experience insights, they reflect the views of a relatively small number of participants.

Evidence on effectiveness of public health messages disseminated for adverse weather events

This chapter summarises evidence on the effectiveness of public health communication. Ultimately, public health communication aims to reduce morbidity and mortality resulting from an adverse weather event (Health Canada, 2020). However, none of the items included in this review directly investigate the link between public health communication and mortality, and only a few make the link between communication and health outcomes (including health services use). Most focus on linking public health communication to what Health Canada (2020) calls intermediate steps towards reduced morbidity and mortality: raising awareness, increasing knowledge, changes in health-related behaviour (or intended behaviour change), developing skills for behaviour change. We present evidence around these outcomes in the next sections.

In 4.1 we present findings from the three studies that evaluated targeted communication interventions. All three identified changes in behaviours, and two identified changes in health outcomes. In 4.2 we synthesise the evidence from four studies that examined associations between exposure to general heat-health messaging and self-reported awareness, recall, and behaviour change (or intentions) in real-world settings. Findings across these studies suggest a more uneven pattern: heat-health messages can be associated with increased awareness and reported protective action for some groups, but effects can be modest and do not reliably extend to those most at risk.

Evidence from targeted intervention studies

Robust evaluations using experimental designs to assess the effectiveness of public health communication on behaviour change are comparatively rare. Three such studies, all related to heat (Mehiriz, 2018; Nitschike et al., 2017; Takahashi, 2015), evaluated the impact of specifically designed communication interventions on health protective behaviour during heat waves on vulnerable people in Canada, Australia and Japan respectively. The two studies using RCTs also examined impact on health outcomes (Mehiriz et al, 2018; Nitschike et al., 2017), and the study using the quasi-experimental design measured changes in knowledge of heat-adaptive behaviours (Takahashi, 2015).

Four key findings emerge. First, all three studies showed a statistically significant difference in health protective behaviour between treatment and control groups. Those receiving ‘treatment’ in the form of health advice (e.g. via warnings, information packages or automated phone warnings) were more likely than those not receiving those messages to adopt protective behaviour.

The sub-set of two studies using RCT designs found a link between changed behaviour and health outcomes. Nitschike et al.’s (2017) RCT of an information package for older people in Southern Australia during a heatwave found that the intervention was associated with a significant reduction in heat stress, indicating a measurable health outcome linked to the behaviour change. An RCT evaluating the impact of an automated telephone message warning vulnerable people of heat episodes and providing recommendations about protecting their health in such circumstances (Mehiriz et al., 2018) identified a reduction in health service use among a sub-group of message recipients (women and particularly women with chronic illnesses). The treatment group adopted more of the recommended behaviours than the control group, though the study did not find a reduction in heat related illnesses.

Second, the quasi-experimental study by Takahashi et al. (2015) suggests that behaviour change effects of public health communication can be enhanced with reinforcing interventions. They found that supplementing the heat health warning with receipt of bottled water led to the adoption of additional protective behaviours and better performance regarding frequency of water intake and cooling the body compared to the control group that only received the heat health warning. Importantly, these behaviour changes occurred in the absence of increases in knowledge and awareness of how to prevent heat related illness. The authors suggest that the physical presence of the water bottle functioned as both a prompt and an enabler, acting as a visible reminder of exactly what to do.

This leads to a third finding from this study: improvements in knowledge and awareness are not preconditions for behaviour change.

Fourth and finally, Meheriz et al. (2018) suggest that paying attention to intersections when analysing the results of heat messaging interventions (and, arguably, designing messages) is important, as these interventions may benefit different subgroups differently.

Evidence from ‘real world’ campaigns

Four studies in our corpus examine public responses to general heat-health messaging delivered through campaigns and alerts in ‘real-world’ settings (Erens et al., 2021; Lefevre et al., 2015; Oakman et al., 2010; Williams et al., 2019). These real-world exposure studies investigate whether people recall hearing health protective advice and whether they report changing their behaviour as a result.

Across these studies, the relationship between exposure to advice and self-reported behaviour change is not consistent. Hearing public health information is associated with stronger intentions to act for some individuals, but effects can be modest and uneven. In a UK-wide survey conducted in October 2013 to examine public responses to heat protection messages during the 2013 England heat wave, Lefevre et al. (2015) found a positive link between hearing heat-protection recommendations and intentions to implement them. Oakman et al.’s (2010) evaluation of the Beat the Heat: Don’t forget your Drink Campaign in Australia and Williams et al.’s (2019) survey of knowledge, attitudes and behaviour of the general population during the 2017 heatwave in England show a modest effect on self-reported behaviour change: 54% and 42.9% respectively of people hearing heat health advice reported changing their behaviour as a result.

The studies also indicate that behavioural responses vary across population groups. Women (Oakman et al., 2010), people with limiting long-standing illnesses (LLSI) (Williams et al., 2019), and younger people (Lefevre et al., 2015) were more likely to adopt protective behaviour. Erens et al. (2021) found that fewer than one third (26.8%) of older people (75 years and over) and just over a quarter (25.6%) of adults in poor health reported changing their behaviour after hearing heat-health advice issued during the 2013 England heat wave. This suggests that some population groups potentially at risk are not very likely to take protective action.

This lag between message exposure and behaviour change is also supported by the wider literature on determinants of risk perception and behaviour. In the heat literature, nationally representative survey evidence (British Red Cross, 2023), systematic and narrative reviews of heat-protective behaviours and behavioural determinants (McLoughlin et al., 2023; Vu et al., 2019), and several empirical studies (Li and Howe et al., 2023; Olson et al., 2023; VanderMolen et al., 2022) collectively point to a gap between awareness of risk and the uptake of protective action. The same observations emerge from literature on floods (Henderson et al. 2022) and drought (McClymont et al. 2022). Together, this body of evidence shows that there is no linear relationship between awareness and knowledge of the health risk associated with an extreme weather event and taking protective action.

Summary

The three intervention studies show that public health communication can encourage behaviour change with consequences for health and health service use. Individual studies further suggest that these outcomes can be enhanced by providing supplementary interventions (such as water delivery) and can differ by population group. Evidence from real-world campaigns, however, paints a more complex picture. It shows that providing information can encourage some people to change behaviour. However, some of those most likely in need of protection are less likely to do so.

The role of risk perception

Risk perception refers to how individuals assess both the likelihood of a hazard and their own susceptibility to its consequences. This is described as part of a ‘threat appraisal’ process, which includes both perceived risk (how likely the threat is) and perceived vulnerability or susceptibility (how likely it is to affect them) (McLoughlin et al., 2023; Olson et al., 2023). These factors are important predictors of protective action: individuals who perceive themselves as personally at risk from health-related threats are more likely to adopt protective or adaptive behaviours (Henderson et al., 2022; McLoughlin et al., 2023).

Given the maturity of the literature on factors influencing risk perception and behaviour, our evidence search for this research question was designed to prioritise the strongest available evidence, particularly evidence reviews. As a result, this chapter draws on 11 evidence reviews examining risk perception, behavioural determinants, and factors affecting effective communication across heat (n=3), heat and cold (n=1), drought (n=1), mixed hazards (n=4), and flooding (n=2). However, evidence relevant to this question was discussed across a broader proportion of the included literature. The review evidence is therefore supplemented by empirical and practice-based literature which includes studies directly examining: factors affecting risk perception and protective behaviour across heat (n=8) and heat and cold (n=1); and communication practices and message content through a behaviour change lens across heat (n=5) and drought (n=2). These are further supplemented by two practice-based communication toolkits focused on heat and drought communication.

This chapter presents findings from included studies, focusing on: knowledge and awareness (section 5.1), the role of experience and proximity to an extreme weather event (section 5.2), efficacy (Section 5.3), the role of emotions (Section 5.4) as well as temporal and spatial issues (Section 5.5), socio-demographic and socio-economic factors (section 5.6) and the role of social norms and trust (section 5.7). Woven into this narrative are findings from our stakeholder engagement to illustrate points made in the literature.

Knowledge and awareness

Although providing information can have a positive effect, the reach of these communications is uneven. Erens et al. (2021) found that only just over half of respondents (51.0%) reported being aware of hot-weather-related health publicity or advice during this event. This increased to about two-thirds (63.9%) of respondents who were vulnerable. Williams et al (2019) found older people aged 75 and over, as well as residents of warmer regions like the Southeast of England, were more receptive to hearing health protection messages, as are households with children (Williams et al., 2019) and women (Oakman et al., 2010). Evidence from multiple weather events and drought further suggests that groups on low income and digitally excluded (Coombs et al., 2024; McClymont et al., 2022) appear to be less likely to access or hear advice. These studies show that already at the first step (accessing or hearing messages) public health messages can fall short in reaching a substantial portion of audiences.

Beyond this, hearing or being aware of messages does not necessarily translate into understanding, retaining or absorbing the information conveyed (British Red Cross, 2023; Erens et al, 2021; Henderson et al, 2022; Olson et al, 2023; Ratwatte et al, 2022; McIntyre et al, 2019; VanderMolen et al, 2022; Vue et al, 2019). The 2023 British Red Cross survey found that those most at risk from heat – including pregnant women and those with a child under three (29%); people who work outdoors (62%), and those with a heart condition (57%) – did not know how to protect themselves.

But even among those who are well informed, many do not take action. Erens et al. (2021) report that people had only partial knowledge of heat-protective actions after hearing the 2017 heat-health advice. Vulnerable people have been shown to be affected because of challenges with complex language, information overload and contradictory information (McIntyre et al, 2019). Older people can suffer from poor message recall and a lack of understanding of what to do (Vu et al., 2019). This was also highlighted in our engagement activities.

Our stakeholder engagement with Scottish organisations representing ethnic minority groups and Gypsy Traveller communities found that literacy barriers can be a challenge to understanding public health messaging. In the case of ethnic minority groups, some may not understand English or understand new weather concepts. If members of Gypsy Traveller communities experience literacy challenges, they tend to navigate digital devices using visual cues (such as remembering app icons) and peer to peer learning. Scottish organisations working with people from warmer climates and for whom English is not their first language said that concepts such as “cold water shock” may be completely unfamiliar.

There is thus no linear relationship between risk communication and behaviour change (Olsen et al, 2023; VanderMolen, 2022; Henderson et al, 2022). Indeed, the wider literature on heat (British Red Cross, 2023; Li and Howe, 2023; McLoughlin et al., 2023; Olson et al., 2023; Tan et al, 2024; Takahashi et al, 2015; VanderMolen et al., 2022; Vue et al., 2019) and flooding (Henderson et al, 2022) suggests that there is no direct causal link between awareness and knowledge of the health risk associated with an extreme weather event and taking protective action.

Experience of adverse weather

Direct, tangible experiences can shape perceptions and actions, often more powerfully than information alone.

Studies on heat show that negative health-related episodes (such as illness, exhaustion, or severe discomfort) are more influential than simple exposure to high temperatures (Bruine de Bruin et al., 2016; Esplin et al., 2019; Lefevre et al., 2015; McLoughlin et al., 2023; Williams et al., 2019). These encounters make risk feel concrete and increase receptivity to guidance and intentions to act. Although the evidence base for cold is smaller, it shows a similar pattern: Ratwatte et al. (2022) report that older adults who had not recently experienced illness during extreme temperatures tended to downplay their vulnerability.

Drought appears to have a distinct challenge: absence of experience leads to a lack of interest in the topic in places like Scotland and Ireland (Antwi et al, 2022). The lack of personal and collective memory of drought in the UK make it harder for people to draw on lived experience when interpreting risk (Weitkamp et al., 2020). Moreover, “drought issues are much less personal unless people are directly affected, such as no water coming out of the tap” (Global Water Partnership, 2019 p. 20). This lack of experiential reference points weakens drought risk perception and limits the ability of communicators to activate the ‘availability heuristic’- the cognitive process through which people judge risks based on how easily relevant examples come to mind. However, where drought experience does exist, for example in regions reliant on private water supplies (e.g. rural communities), it can heighten awareness, perception, and preparedness (McClymont et al., 2022), which also illustrates how spatial context acts as an intervening factor.

Our place-based engagement work with Dumfries and Galloway highlighted that while many local residents understand flood dynamics and take precautions like checking river levels themselves, tourists and new residents often fail to heed warnings, due to lack of experience or underestimating the risk. Residents we spoke to described people not from the area driving through flooded roads despite clear signage, leading to hazardous situations.

Experience therefore functions as a form of evidence, ‘anchoring’ risks in memory, shifting them from abstract to tangible, and heightening perceived personal susceptibility. This explains why several studies suggest using communications that prompt recall of negative or uncomfortable prior experiences to strengthen engagement (Bruine de Bruin et al., 2016; Esplin et al., 2019; Lefevre et al., 2015; Li et al., 2018; McLoughlin et al., 2023).

Efficacy as a bridge to action

However, recognising a threat is not always enough. A well-documented phenomenon, often referred to as the “risk perception paradox” (Wachinger et al., 2013), shows that people can be aware of a threat and acknowledge personal vulnerability, yet still fail to take protective action. Protection Motivation Theory (PMT) (Forsyth et al., 2023; Henderson et al., 2022; Tan et al., 2024) is one framework that clarifies the process of ‘conversion’ from perceiving a risk to being motivated to act. It suggests that protective action depends not only on perceiving a risk (threat appraisal) but also on ‘coping appraisals’ (McLoughlin et al., 2023), which include believing that the recommended protective actions are effective (response efficacy) and achievable (self-efficacy), and that the costs of those measures are affordable.

These beliefs consistently emerge among the strongest predictors of adaptive behaviour, surpassing knowledge-based determinants and demographic factors (Bourret Soto et al., 2024; British Red Cross, 2023; Erens et al, 2021; Forsyth et al., 2023; Henderson et al., 2022; Lefevre et al, 2015; McIntyre et al., 2022; McLoughlin et al., 2023; Ratwatte et al., 2022; Tan et al., 2022; Turner et al., 2024). Tan et al. (2022) found that self-efficacy, response efficacy, and personal attitudes exerted the strongest influence on protective behaviours across disaster types, a finding supported by McIntyre et al. (2022). The importance of efficacy beliefs also emerges in evidence reviews across heat (Bourret Soto et al., 2024; McLoughlin et al., 2023), floods (Forsyth et al., 2023; Henderson et al., 2022), and heat and cold (Ratwatte et al., 2022).

UK-based empirical studies on heat also support these findings (British Red Cross, 2023; Erens et al, 2021; Lefevre et al, 2015), with both Lefevre et al. (2015) and Erens et al. (2021) showing that perceived effectiveness of recommended behaviours was a strong determinant of, respectively, intention to act or self-reported behaviour change during heat events. Erens et al. (2021) further found that different socio-demographic groups perceive different recommended protective measures as highly effective. Adults potentially vulnerable to heat because of chronic conditions showed the lowest confidence in the effectiveness of most recommended behaviours compared to the other groups.

Even when a behaviour is perceived as effective, people may not act on it. For example, practical reasons can get in the way, inhibiting adoption of risk-mitigating behaviours. These can include one’s capability to act (e.g., physical mobility, literacy), opportunities and access to interventions (e.g., vehicle to drive to cooling centre, financial resources to invest in or run air conditioning or safety concerns (e.g. when opening windows).

These findings are consistent in several studies on heat (British Red Cross, 2023; Erens et al., 2021; Esplin et al., 2019; Olson et al., 2023; Heat Health Canada, 2020; Vu et al., 2019; Tetzlaff et al., 2025b), and extend to heat/cold (Turner et al., 2024), floods (Henderson et al., 2022) and drought (McClymont et al., 2022) which also suggest that individuals balance awareness and intent against the financial, physical, and practical realities of implementation.

During our engagement events with Scottish organisations working with parents and carers of infants and young children, participants shared that single parents face logistical challenges, such as finding childcare to leave the house, for necessary preparations such as topping up pay-as-you-go electricity meters. Keeping warm in cold weather is expensive, especially in energy-inefficient housing; running fans or stalling air conditioning for rising temperatures also poses a cost barrier for low-income families. Cultural factors can shape propensity to act. Organisations working with diverse communities mentioned that strict cultural gender roles, e.g. in the Gypsy Traveller community, can mean women may not take actions deemed to be ‘men’s work’.

Perceived control, or the belief that actions can make a difference, also matters. Studies on floods (Henderson et al., 2022), heat (McLoughlin et al., 2023), and heat and cold (Ratawatte et al., 2022; Turner et al., 2024) suggest that stoicism or fatalism (‘putting up with it’) can reduce motivation by viewing weather as something to ‘endure’ rather than manage. This reflects an external locus of control, where events are seen as governed by fate or nature, lowering the perceived value of action. While the relationship between perceived control and behaviour is mixed, Ratawatte et al. (2022) found one study which showed that reframing messages to emphasise individual agency, i.e. supporting an ‘internal locus of control’, increased perceived risk and adaptive intentions.

During our engagement events organisations working with diverse communities mentioned the faith-based culture of the Gypsy Traveller community, with its deep belief in omens and signs. This can lead members to prioritise faith over taking immediate, practical safety measures.

Esplin et al. (2019) and Henderson et al. (2022) further highlight that motivation can be undermined by a limited sense of personal responsibility, whereby individuals shift responsibility onto others (e.g. governments) and therefore do not act.

The role of emotions

Discomfort, fear and concern can mediate the relationship between heat exposure and protective intentions. Yet in the UK, while concern about hot summers is rising (British Red Cross, 2023; McLoughlin et al., 2023), positive associations with warm weather are still prevalent and dilute these effects (Bruine de Bruin et al., 2016; Erens, 2021; Lefevre et al., 2015; Turner et al., 2024; Weitkamp et al., 2020; Williams et al., 2019).

Analysing responses to the 2013 UK heatwave, Lefevre et al. (2015) found that while heat-protection messages appeared to strengthen beliefs that recommended actions would be effective, they were also associated with more positive emotions about heat, which in turn reduced uptake of protective behaviours. The authors argue that, in the UK context, warnings about hot weather may inadvertently trigger positive memories and emotions associated with summer, thereby weakening the perceived need for protective action. Bruine de Bruin et al. (2016) tested whether recalling past unpleasant temperatures was linked to intention to take up health protective behaviours. Their UK-based experimental study on messaging strategies found that asking people to recall the “most unpleasant highest temperature” successfully triggered memories of unpleasantly hot weather and increased intentions to engage in heat-protection behaviours. By contrast, asking participants to merely recall the highest temperature led to pleasant memories of warm weather, reducing motivation for protection; asking participants to recall the most unpleasant temperature in the summer typically led them to recall cold (summer) weather, which did not encourage heat protection.

Our stakeholder engagement workshops illustrated how negative experiences with cold can lead to fear and impact on individuals’ capacity to access help. One workshop participant shared the experience of a friend being very scared of going out after falling during cold, slippery weather two years prior. Another participant recalled a personal and scary experience of falling while pregnant and walking to the GP in bad weather, highlighting the difficulty of accessing essential services like GPs during extreme weather, especially when a person is vulnerable. In the Gypsy Traveller community, older generations can interpret messages very literally, leading to extreme fear from generalised news warnings.

Drought inherits similar emotional biases. Dry weather in the UK is often viewed positively because it typically co-occurs with sunshine. Weitkamp et al. (2020) describe an informal ‘weather hierarchy’ in which sunny, dry days are valued over cool, wet ones, making it difficult to frame drought as a risk. In the case of flooding, fear can prompt defensive coping (denial, fatalism, or disengagement) unless people know how to protect themselves (Forsyth, 2022). Similarly, Tan et al. (2022), covering multiple hazards (including flooding), found that negative affect (fear, worry, anxiety) had only a moderate effect on protective behaviour, compared with response and self-efficacy. Bruine de Bruin et al. (2016) reinforce this point, noting that emotion-based strategies may still fail if people do not understand why or how a behaviour is effective.

Temporality and spatiality

Temporality and spatiality shape experiential and emotional processes. Temporal context involves timing and sequence of experience and communication: how proximity in time and recent weather influence perceptions of risk as urgent or remote, credible or irrelevant. Bruine de Bruin et al. (2016) found that a message sent three months after a heatwave during cooler weather made people recall ‘highest temperatures’ as pleasant, reducing protective intent. When messages were sent during hot spells, people recalling ‘unpleasant temperature’ were more likely to remember hot days as unpleasant. The positive feelings associated with hot weather were weaker, making heat seem more unpleasant. Therefore, recent, vivid discomfort increases perceived relevance, while memories soften or become more positive over time, especially after cooler weather.

For drought, temporality operates differently. Its slow onset nature can create ‘temporal invisibility’, making it difficult for people to recognise it as a developing or personal risk (Weitkamp et al., 2020). In addition, if rainfall coincides with official drought messages, people may struggle to reconcile those messages with the immediate experience of rain (e.g., McClymont et al., 2022). Although the literature on drought focuses on water use and warning systems (outside the scope of this RER), its broader relevance lies in further illustrating how factors such as timing, sequencing, and contextual alignment can shape whether communication is perceived as credible, plausible, and personally relevant.

Spatial context includes geographical location and living environments, influencing exposure and proximity to weather. Urban areas experience stronger heat-island effects, which increase awareness (Health Canada, 2020; Tetzlaff et al., 2025a). Housing conditions such as top-floor flats or poor insulation increase exposure to heat or cold. Older adults in southern England see themselves as less at risk from heat than those in the Midlands or North, despite higher temperatures, likely due to climatic normalisation or coping routines (Turner et al., 2024). Residents in Scotland and Northern Ireland, where temperatures are cooler, are less likely to take heat-protective actions, indicating lower perceived relevance (McLoughlin et al., 2023). For drought, rural households face water scarcity directly and are more prepared (McClymont et al., 2022), while most UK residents find drought abstract (Weitkamp et al., 2020).

Socio-demographic and socio-economic factors

Public health communication on adverse weather events is often particularly concerned with protecting socio-demographic groups considered vulnerable. Its effectiveness therefore relies on these demographics recognising their vulnerability and taking the recommended protective action.

However, the evidence from this RER shows that socio-demographic and socio-economic factors alone do not reliably predict how people perceive weather-related health risks or their behavioural responses, as these factors interact with psychological and contextual mediators. For instance, people living in poorer neighbourhoods and minoritised groups often report higher heat-risk perceptions, reflecting heightened exposure (McLoughlin et al., 2023). Yet responses are shaped by personal characteristics and systemic inequalities such as cost, housing conditions, physical capacity, digital access, literacy and language -factors that influence whether people receive, interpret and feel able to act on advice (linked to self-efficacy). For example, Tuner et al. (2024) found that risk perceptions of cold weather varied by socio-economic characteristics, likely indicating that those with more resources are better able to implement health-adaptive behaviours (e.g., keeping homes warm).

Age, too, does not determine behaviour. Evidence on heat and cold shows that older adults do not necessarily identify themselves as at risk (British Red Cross, 2023; Esplin et al, 2019; Li et al., 2018; Li et al., 2023; Olson et al., 2023; Ratawatte et al., 2022; Turner et al., 2024; VanderMolen et al., 2022; Vu et al. 2019; Williams et al., 2019). For example, Vu et al.’s (2019) systematic review of literature on heat health prevention measures and adaptation in older populations showed that many older people surveyed in Australia, UK, and USA/Canada did not feel they were susceptible to heat-related illness and did not feel they should stop daily activities. Williams et al. (2019), who also examined older people and those with limiting long-standing illness (LLSI), found that most participants in those categories did not consider their health to be at risk during hot weather. However, they were more likely to identify risk in others. This aligns with findings from Li et al. (2023) and Esplin et al. (2019) that individuals may accept group-level risks but exclude themselves due to active self-identification as healthy or capable. Moreover, age-related factors such as forgetfulness, reduced message recall, and absence of prompts, particularly for those living alone, still shape how older adults engage with advice (Erens et al., 2015; Vu et al., 2019). This again indicates that what matters is not age itself but how individuals interpret their vulnerability and capability, suggesting that communication strategies should take such considerations into account.

The same holds for health status. For heat and cold, Turner et al. (2024) and Ratawatte et al. (2022) found that individuals who are health-conscious, managing chronic illness or had comorbidities were more likely to engage in protective behaviours. Specifically related to heat, Lefevre et al. (2015) and Erens (2019) found that being older, female, and prone to adverse effects or poorer self-reported health were associated with greater adoption of certain protective behaviours. Again however, perceived effectiveness of an action emerged as a stronger predictor of uptake, overriding the effects health status (and age) alone.

Data on gender are consistent: women report higher risk perception, message recall and concern, and are more likely to modify their behaviour (e.g. Bourret Soto et al., 2024; Henderson et al., 2022; Mehiriz et al., 2018; Oakman et al., 2010). Despite this significance, other factors intersect, such as beliefs about the effectiveness of recommended behaviours (Bourret Soto et al., 2024; Esplin et al., 2019; Lefevre et al., 2015; McLoughlin et al., 2023; Tan et al., 2024; Williams et al., 2019). The recurrent pattern of lower perceived risk among men has led one study to explicitly suggest an engagement gap that may merit targeted communication approaches (Bourret Soto et al., 2024). This phenomenon was also highlighted by Scottish organisations involved in our stakeholder engagement, who observed the same pattern among other population groups.

A Scottish youth organisation said that boys and young men aged 12-25, particularly those not attending school, are quite vulnerable to heat as they tend to gather in parks and on beaches without proper sun protection or awareness of dehydration. Yet, they do not view heat and associated health risks such as sunburn as a significant threat and often ignore sun safety advice. And Scottish organisations representing diverse communities thought that climate migrants might underestimate their risk as Scottish weather is more temperate than that in their home countries. This might translate into a false sense of security. One workshop participant shared a personal experience of feeling dizzy and becoming dehydrated in the Scottish heat, noting it’s a different heat than she had previously experienced, and it can be dangerous.

Social norms and trust

Social influence, expressed through norms and interpersonal interactions, can play a role in shaping adaptive behaviour. Cues to action from trusted community figures and peers can help normalise protective action by making adaptive behaviours appear both common and socially approved. These dynamics operate through descriptive norms (what others typically do) and injunctive norms (what others believe one ought to do), both of which have been shown to influence intentions and behaviour in the context of adverse weather (Forsyth et al., 2023; McLoughlin et al., 2023; Tan et al., 2024). Such cues carry both descriptive and injunctive weight: they show that protective behaviours are socially visible and socially endorsed. McLoughlin et al. (2023) also note that some studies have found that their effect is strongest when individuals feel they have perceived control, showing how coping appraisals remain relevant as well.

Prosocial norms add another layer, although the evidence is weaker. One study (Esplin et al., 2019) shows that norms grounded in altruism, care and reciprocity, such as encouraging people to “check on neighbours”, can motivate behaviour. The study did find age differences in this regard, with older adults often expressing altruistic motivations, acting to safeguard others’ wellbeing, whereas younger adults focusing more on self-protection. The authors concluded that tailoring communication to these orientations could strengthen engagement. For example, interactions with older adults can emphasise the need to take care of one’s health so that one can help others effectively, and outreach to younger adults can encourage them to be more aware of vulnerable people around them and what they can do to help. However, because not everyone is embedded in strong social networks, messaging must avoid assuming access to family or community ties (Tetzlaff et al., 2025a).

Finally, numerous studies highlight trust as an important predictor of protective behaviour (Coombs et al., 2024; Fathollahzadeh et al., 2023; Forsyth et al., 2023; Global Water Partnership, 2019; Health Canada, 2020; Henderson et al., 2020; McIntyre et al., 2019; VanderMolen et al. 2022; Weitkamp et al., 2020). Trust in institutions, authorities and information sources affects whether public health messages are believed, prioritised or dismissed. High trust can strengthen response efficacy (confidence that guidance will help), whereas low trust can create scepticism or resistance, even when messages are well-designed. This points to the importance of considering not only message content, but also who delivers information, which will be discussed in Chapter 7.

Summary

Risk perception and behavioural responses to adverse weather emerge from the interaction of multiple influences. Socio-demographic and socio-economic characteristics shape opportunities and constraints; personal experience, proximity, emotion, and the wider spatial, temporal, and cultural contexts condition whether risks feel salient; efficacy beliefs translate risk perception into motivation; social norms, cultural identities, and trust influence whether protective behaviours are viewed as credible, relevant, and socially supported.

The evidence converges on several common themes:

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  Experience and emotion make risks tangible, but their influence depends on wider contextual cues and on whether individuals believe action is both possible and worthwhile.
  
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  Efficacy consistently emerges as a central mechanism linking perception with action, although it is sensitive to structural barriers.
  
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  Social and cultural environments—including prevailing norms, collective narratives about weather, and trusted relationships with messengers—shape how people interpret advice and whether they act on it.
  
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  Demographic factors amplify rather than predict behaviour, operating through intervening cognitive and contextual processes.
  

Taken together, the findings reinforce the value of viewing behavioural responses as the outcome of interconnected processes, shaped simultaneously by individual interpretation and the wider conditions in which people live.

Implications for public health communication

Considering this complex web of factors shaping the relationship between exposure to public health communication on adverse weather and subsequent action, the literature included in this RER, and qualitative evidence from stakeholder engagement highlight several implications for how messages should be designed to support behaviour change.

Persuasive and comprehensible messages

Olson et al. (2023) and Li et al. (2018) argue that messages need to be designed to be persuasive. This requires going beyond merely increasing understanding to include additional information intended to increase message recipients’ perceived severity of the situation and their susceptibility. For example, information about how heat will personally affect an individual can increase perceived severity, which strongly predicts the extent to which individuals adopt heat-mitigation behaviours. However, the authors’ quantitative content analyses of official heat-related tweets found that agencies underuse such message components. Although both studies focus on official agency communication during extreme heat events rather than public health messaging more broadly, they nevertheless provide transferable insights: behaviour change is more likely when messages actively engage perceptions of personal relevance and risk, rather than relying on information provision alone.

Messages must also be designed so that recipients can easily absorb their content, and audiences need to correctly understand the message (Coombs, 2024; Health Canada, 2020; McClymont et al., 2022; Olson et al., 2023; Tetzlaff et al., 2025a). According to Coombs et al.’s (2024) scoping review on factors affecting public health communication, current research highlights the importance of tailoring public health messages to specific audiences by considering language and literacy diversity, income levels, geographic differences, and health and other needs and preferences. Tetzlaff et al. (2025a) used terms such as ‘living space’ or ‘cooler area’ instead of ‘house’ or ‘basement’ when revising heat-health warning messages to reflect varied housing conditions. Similarly, Health Canada’s good practice toolkit (2020) emphasises that messages should address the audience’s abilities and unique challenges and perspectives. Practical advice from this body of literature is:

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  User testing of messages with diverse (including vulnerable) groups to identify misunderstandings, knowledge gaps, or ineffective phrasing (Olson et al., 2023).
  
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  Readability testing to ensure messages can be read and understood by audiences with lower health literacy, non-native speakers, or newcomers (Tetzlaff et al., 2025a).
  

Beyond this, McLoughlin et al. (2023) recommend practical inclusivity measures such as messages in multiple languages to reach tourists, using creative forms of communication (e.g. art, soap opera storylines, late-night radio) and designing materials that resonate with specific audiences (e.g. eye-catching leaflets, for example for older adults).

Literature across heat (Bourret Soto et al., 2024; Health Canada, 2020; Oakman et al, 2010; Olson et al., 2023; Tetzlaff et al., 2025a; VanderMolen et al., 2022), flooding (Forsyth et al., 2023; Henderson et al., 2022) and drought (McClymont et al., 2022; Weitkamp et al, 2020) further argues that messages need to include actionable guidance which explains the rationale behind protective behaviours. For example, Oakman et al.’s (2010) study of the Australian “beat the heat” campaign showed messaging suggesting concrete daily quantities for liquid intake of 1.5-2l was effective in provoking recall of the message and what to do in heat (drinking water). Tetzlaff et al.’s (2025a) review of heat warning messages with public health and climate expert input started all messages with verbs (e.g. check, drink, plan, move, monitor) to make them directive and concrete and increase their potential to encourage protective behaviours. This can be supported by including simple infographics and daily schedules (Bourret Soto et al., 2024).

A focus on action is also a key message coming out of our stakeholder engagement, especially action that is low-cost and realistic which recognises differences in financial situations. Scottish organisations argued that general advice such as putting “baby items” in grab bags for emergencies does not inspire action without specifying what these items are (like nappies and bottles).

This guidance also needs to recognise that an adverse weather event can be experienced differently across spatial contexts. For example, people in rural areas experience and respond to heat differently from those in densely populated cities. They may also have more limited access to specific resources (e.g. cool or warm places to go to) (Tetzlaff et al., 2025a). Given that certain socio-economic factors may prevent people from changing their behaviours, communication is more likely to change behaviour when complemented by programs that remove barriers to action and provide opportunities for citizens to adopt coping strategies (e.g. providing free bus tickets to people during extreme heat will encourage them to go places where they can cool down) (Health Canada, 2020). Devising these programmes is, however, out of control of public health communicators.

Beyond this, Health Canada (2020) recommends that message content be simple, specific, and motivating, and that it use plain, jargon-free language and personal pronouns (‘you’). Based on a qualitative content analysis of heat health information on public health websites, Tetzlaff. et al (2025a) argue that message content It should be evidence-based, using simple infographics, directly mentioning the most important contexts where the risk is greatest.

In our engagement with Scottish organisations representing diverse communities, they recommended the use of storytelling to deliver the message more effectively. For example, through faith-based teachings or community gatherings.

Communicating the benefits of health advice

Evidence from qualitative (VanderMolen et al., 2022) and quantitative (Li et al., 2018; Olson et al., 2023) empirical studies as well as systematic and scoping literature reviews (Bourret Soto, 2024; McLoughlin et al., 2023) focusing on heat conclude that to evoke belief in the effectiveness of a measure, public health messaging needs to go beyond describing (heat) advice to also indicate why a particular behaviour is crucial to protect oneself. This information can increase perceived response efficacy (i.e., the belief that the behaviour is effective in mitigating a threat) and self-efficacy (i.e., confidence in their ability to act). Both have a powerful effect on behaviour change. Therefore, the association between the hazard and the protective action should be included in the message (McLoughlin et al. 2023):

Prior experience: “Think back to the last time you felt overwhelmed by the heat, perhaps sick or faint with heat stress. This is the reality of heat risks consequences.”

Addressing positive affect: “While in the past we may have looked at summer heatwaves as reasons to feel positive, we must now view such events with concern. Heat risks can lead to death and lasting health consequences.”

While emotions influence perceptions and behaviours, evidence across hazards remains mixed regarding its effectiveness as a behaviour change tool on its own. What emerges consistently, is that emotional or experiential cues alone are insufficient unless combined with efficacy information. McLoughlin (2023) emphasises that while fear or concern can heighten responsiveness, they are effective only when accompanied by clear, actionable guidance. Evidence from flood-preparedness research mirrors this finding: Forsyth (2022) shows that messages inducing fear without efficacy prompts often lead to defensive coping, such as denial, fatalism, or disengagement, whereas those combining fear with practical steps encourage problem-focused coping. Similarly, Tan et al. (2022) found across multiple natural hazards (including flooding) that negative affect (fear, worry, anxiety) had only a moderate effect on protective behaviour compared with response and self-efficacy. They caution that relying on fear alone is unlikely to produce sustainable changes in behaviour.

Maintaining personal relevance

As people do not like to think of themselves as vulnerable, messaging that uses vulnerability labels may reduce personal relevance and weaken engagement (Erens et al., 2021; Ratawatte et al., 2022; Turner et al., 2024). “Public health messages should avoid labelling individuals as ‘vulnerable’ when raising awareness of the risks of hot weather, even among those who fit the definition” (Erens, 2021). Evidence from a systematic review on heat (Bourret Soto et al., 2024) and an RCT on heat risk messaging (Li et al., 2023) show that designing messages to emphasise “everyone can be at risk” can be effective instead.

Li and Howe (2023) examine this in depth, specifically testing different framings in heat-risk messages targeted to the general public. The study is informed by the broader body of research suggesting that underestimation of personal risk, i.e. low ‘perceived susceptibility’ or lack of ‘personalisation’, is a key psychological barrier to taking protective action during extreme heat events. They compared four versions of a public-facing heat risk message that varied in how they depicted which types of people were susceptible to heat-health impacts. They included: subgroup-only framing (mentioning older adults, children, people with chronic diseases, and outdoor workers); universal “everyone can be at risk” framing (illustrated in Figure 2); a combination of both; and a neutral framing. Outcomes measured included perceived message relevance, belief in hazard occurrence, perceived susceptibility, and behavioural intention.

Figure 2: “Everyone can be at risk” message example (Source: Li et al., 2023)

Universal ‘everyone can be at risk’ framing produced significantly higher perceived personal relevance than subgroup listing, which scored lower on relevance even than a neutral version with no susceptibility information at all, suggesting that listing vulnerable groups in a message targeted to the general public can actively work against engagement among those who do not identify with them. This is particularly relevant given evidence suggesting that many older adults, for example, do not perceive themselves as personally vulnerable to heat, while younger people may interpret subgroup-focused warnings as implying that the threat applies mainly to others rather than to themselves. While this study is about large-scale communications that need to appeal to everyone rather than routine public health messaging, the underlying principle is transferable: how susceptibility is depicted in public-facing communications affects whether people feel the message is personally meant for them.

At the same time, improved relevance did not translate into higher perceived susceptibility or greater intention to take protective action, indicating that while relevance is a crucial first step for ‘attention’ and engagement with the message, it is not sufficient on its own to drive behaviour change. In addition, the study also found some differences: younger adults were more responsive to universal framing, while adults aged 30-44 responded more to combined ‘anyone plus subgroup’ wording. A related finding is that adding subgroup labels to universal framing weakened some of the benefits of the universal approach and, in some cases, reduced belief that the heat event would actually occur, suggesting that this may be because combining both framings sends mixed signals about who the warning is primarily intended for, potentially undermining both personal relevance and message credibility.

These findings together highlight the need to balance personal relevance, message clarity, and audience diversity in the design of heat-risk communication. They also suggest that no single framing approach is likely to work equally well across all population groups, meaning that more segmented or tailored approaches may still be needed to communicate heightened susceptibility in ways that feel personally relevant and meaningful to different audiences.

In our stakeholder engagement events, organisations representing older adults and those with chronic health conditions advised that emphasising empowerment and action rather than labelling the recipients as “vulnerable”. Being labelled as vulnerable can be a turn-off and negatively affect the message’s reception. Empowering messaging through language is more likely to inspire positive action. And they shared that generic national advice on flooding is often met with “optimism bias”, where people assume the warning is for “the people who are at risk, it’s not me”. This highlights the need for messaging to more clearly articulate the risks to everyone.  

Turner et al.’s (2024) analysis of two nationally representative surveys of older adults’ risk perceptions covering heat and cold provide a practical example of attending to message relevance in relation to labels. Findings suggest that older adults may respond better to guidance framed around peers (“people your age”) or situational markers (such as living alone) rather than age-related labels such as “65+”.

In relation to message content, several studies (Olson et al., 2023, Li et al., 2018; VanderMolen et al., 2022) suggest that segmented communications aimed at groups at heightened risk may be more effective when they make explicit the connection between the hazard and the factors that put someone at risk, supporting people to identify with and personalise the risk. However, content analyses of National Weather Service Twitter messages by both Olson et al. (2023) and Li et al. (2018) for example show that this kind of explanation, illustrated in Figure 3, is rarely included.

Figure 3: Heat warning image focusing on vulnerable populations (Source: Olson et al. 2023)

A qualitative study exploring barriers to heat communication (VanderMolen et al, 2022) aligns with this, recommending that communication interventions should help individuals understand and evaluate their risks with more specificity, as this improves willingness to adopt protective behaviours, for example, when people with chronic illness learn how their conditions increase heat sensitivity.

Olson et al. (2023) provide a further example of wording to illustrate this logic, linking individual or situational characteristics to a concrete mechanism of risk that people can recognise can make it more relevant and meaningful.

“Children cannot cool their bodies easily because they sweat less than adults. This puts them at higher risk for heat stroke, which includes nausea or vomiting, rapid heart rate, or death”. (Source: Olson et al., (2023)

Taken together, this evidence points to a consistent set of principles: avoid vulnerability labels that invite disengagement; use framing that considers how people self-identify/see themselves; recognise that different population segments may respond differently to the same message; and where targeting specific groups, support people to personalise the risk by explaining why they are vulnerable.

Relevance also relates to temporality. Because memories of heat discomfort weaken over time, timely, repeated reminders that link heat to discomfort or health impacts are recommended during the summer (Coombs et al, 2024;Health Canada, 2020). This aligns with research emphasising tailored messages to the phases of the emergency cycle (Tetzlaff et al., 2025b) and seasons (VanderMolen et al., 2022; Health Canada, 2020). This involves early-season communication, intensifying during events, and using the post-event period to reinforce messages, especially after heatwaves (Health Canada, 2020). For example, “we are still recovering from an extreme heat event, continue to drink cool water before you feel thirsty” (Health Canada, 2020). Repeating messages can boost protective intentions (Bruine de Bruin et al., 2016), and VanderMolen et al. (2022) recommend ongoing campaigns on adverse weather (heat).

Consider implications of socio-demographic differences

While socio-economic and socio-demographic factors do not predict risk behaviour, they are relevant for communicators because they shape people’s opportunity, means and motivation to act. This is why consistent implications for messaging, related to content (language, targeting and accessibility), channels and sources, emerge across the literature. This includes the importance of:

• Empowering people to act within their capabilities through clear, achievable actions.
  
• Acknowledging structural and systemic barriers, as advice that overlooks financial, housing or logistical realities risks sounding hollow, being perceived as irrelevant, and undermining trust. For example, telling low-income households to “seek cool spaces” (British Red Cross, 2023; Tetzlaff et al., 2025a) can feel unrealistic unless accompanied by information about available support and language that does not assume standard housing or resources.
  
• Ensuring equitable access to messages, especially for under-reached groups such as those with lower literacy or limited digital access.
  
• Noting that although gender does not predict behaviour on its own, consistently lower risk perception among men indicates a potential engagement gap.
  

Prosocial norms

Esplin et al. (2019) concluded that tailoring communication to the prosocial orientations of different population groups could strengthen engagement. For example, interactions with older adults can emphasise the need to take care of one’s health so they are able to help others effectively, and outreach with younger adults can encourage them to be more aware of vulnerable people around them and what they can do to help. However, because not everyone is embedded in strong social networks, messaging must avoid assuming access to family or community ties (Tetzlaff et al., 2025a).

Heat messaging example appealing to social norms (McLoughlin et al., 2023):

“Growing numbers of people are concerned about heat risks. At the same time, more and more people are taking actions to prepare themselves for heat risks, such as summer heatwaves.”

Summary: features of effective communication

The design of public health messages can support the acquisition of knowledge and awareness and (intended) protective behaviour if it acknowledges intervening factors and applies the following principles:

• Public health communication needs to include actionable guidance (e.g. drink 1.5–2l of water daily) which explains the rationale behind behaviours.
  
• Messages should start with verbs and specify concrete steps. Starting with verbs makes messages directive and concrete and increases their potential to affect behaviour change.
  
• Communicators need to pay attention to “message relevance”: people need to see themselves in the message and believe the message is for them. Broad public-facing communication may be more effective when risk is framed as relevant to “everyone”, rather than only to particular “vulnerable” groups. However, communication for groups at heightened risk still require more tailored approaches. This means considering how people self-identify, and explain why risk applies to particular people to support them to personalise the risk.
  
• Messages need to work with people’s emotional responses to adverse weather events and create messages that evoke emotions in line with the risk. Combining emotional appeals with efficacy information is more effective than appealing to emotions only.
  
• Content needs to be tailored to specific audiences, recognising diversity of communication needs, such as language and literacy needs, housing context, income, and geography. Messages should be kept simple and jargon free, using plain language and personal pronouns (“you”). Carry out readability testing, user testing with diverse groups. This is supported by reviews and good practice guidance.
  
• Language needs to be inclusive, simple, jargon free, and using personal pronouns. Storytelling can be used to deliver the message more effectively, for example through faith-based teachings or community gatherings. Images and infographics can further help people understand what to do and when.
  
• Timing of messages matters. Messages are more effective when sent close to an event and worded in phase with the emergency cycle.
  

Effectiveness of communication channels

Effectiveness of communications depends not only on what is communicated but also on how and through whom messages are transmitted. This dual aspect reflects the broader principle that effective communication must reach and resonate with diverse audiences. Communication channels influence reach and access, while the source shapes credibility, trust, and relatability (Coombs et al., 2024). These dimensions jointly affect whether individuals absorb information, perceive it as personally relevant, and translate it into protective behaviour.

The effectiveness of a communication channel can therefore be understood across two dimensions: reach, the extent to which people receive information; and whether exposure to a given channel is associated with changes in awareness, attitudes, or protective behaviours.

We did not identify studies that have directly tested the causal impact of different communication channels on attitudinal or behavioural outcomes. This limitation is confirmed across several evidence syntheses (Forsyth et al., 2023; Henderson et al., 2022; McIntyre et al., 2019; McLoughlin et al., 2023), which note a general paucity of comparative studies or evaluations that assess which types of channels or ‘messengers’ are most effective in changing behaviour. The result is a notable evidence gap.

This chapter synthesises findings from a subset of 21 of the 32 included items that discuss communication channels across heat (12), drought (3), mixed hazards (4) and floods (2). The dimensions covered include: channels typically used to disseminate adverse-weather information and patterns of access and preferences; how information is accessed or conveyed within a particular medium, with considerations on strengths and limitations in terms of reach and accessibility, with a smaller number of studies providing insights also into the type of information a particular channel can convey; and components of effective communication or factors affecting behaviour with related channel considerations.

Structured around the three main types of channels identified in the literature (traditional channels, digital channels, and social and community networks), this chapter synthesises findings across these three categories, supplemented by our stakeholder engagement discussions.

‘Traditional’ channels

Across all weather events, the evidence suggests that people still value communication via traditional, formal, or one-way channels. These include broadcast media such as TV and radio, and print media such as newspapers, brochures, and leaflets. Such channels have consistently been the most widely used and accessed sources of information on the risks of adverse weather events. This is true both in the UK (British Red Cross, 2023; Henderson et al., 2022; Lefevre et al., 2015) and internationally (Coombs et al., 2024; Health Canada, 2020; McIntyre et al., 2019; McLoughlin et al., 2023; Vu et al., 2019).

Recent UK data confirm this pattern. The 2023 British Red Cross survey on public perceptions of heatwaves found that 74% of respondents had heard about heatwaves from news or weather reports, 39% from the Met Office website, and 22% from local radio stations. Similarly, Henderson et al.’s review on flooding communication in Scotland (2022) highlights the important and well-evidenced role of broadcast outlets in reporting on extreme weather events and sharing practical advice before, during, and after flooding incidents.

These studies underline that traditional broadcast channels remain central to the dissemination of timely and wide-reaching public information, even if levels of trust in these outlets may be mixed (Coombs et al., 2024; McLoughlin et al., 2023).

Print materials, such as leaflets, brochures, and posters, already used in risk communication generally, also retain enduring relevance, particularly for older adults (Health Canada, 2020; Henderson et al., 2022; McIntyre et al., 2019; McLoughlin et al., 2023; Nitschke et. al., 2017; Williams et. al., 2019).

Our discussions with organisations supporting older adults similarly noted that concerns about online scams can make some reluctant to use digital platforms. Instead, older adults highly value physical communication methods such as posters and leaflets.

The advantages of print media lie in their accessibility, familiarity, and physical visibility. They can be distributed through mailings, local services, or community venues, allowing messages to reach people who may not actively seek information online. They can support increase in knowledge (Health Canada, 2020; Nitschke et. al., 2017) or act as prompts to remind people (particularly if they live alone) to adopt particular behaviours, such as drinking water during periods of extreme heat (Williams et. al., 2019).

Broadcast and print formats, therefore, remain effective channels for conveying public information during extreme weather events, including in Scotland (Henderson et al., 2022).

This has led some to recommend that organisations responsible for extreme-weather communication work more closely with the media and deliberately use multiple broadcast and print formats to maximise the reach of their messages (Henderson et al., 2022; McLoughlin et al., 2023; Oakman et al., 2010).

Digital channels: websites and social media

The rise of digital platforms has diversified communication pathways and enabled and empowered individuals to seek health and risk information independently (Coombs et al., 2024). The evidence on their impact on increasing awareness, knowledge, or protective behaviour is limited (Henderson et al., 2020; McLoughlin et al., 2023; McIntyre et al., 2019). However, there is some evidence on their respective strengths and limitations in terms of reach, accessibility, and the type of information they can convey.

Websites

Websites are among the channels most frequently used by public authorities to disseminate extreme weather information (McIntyre et al., 2019) and also rank among those most commonly accessed by the public, in the UK (British Red Cross, 2023; Henderson et al., 2022) and internationally (Tetzlaff et al., 2025a). As such, they represent an important component of communication strategies.

However, access is uneven. Henderson et al. (2022), for instance, point to low engagement with official (flood) websites, attributing this to preferences for face-to-face interaction, overconfidence in existing knowledge which discourages people from proactively accessing information, or limited information-seeking habits. Access also varies across social and demographic groups. Similarly, Coombs et al. (2024) observe that online use tends to differ by language, culture, and socioeconomic status, and a review of drought-related vulnerability in Scotland illustrates this digital divide: while 93% of households report internet access, this falls to 87% in the most deprived areas, compared with 99 % in the least deprived (McClymont et al., 2020). Although online platforms extend the reach of public information, they cannot ensure equitable exposure or engagement across all population groups.

Four studies provide information related to the content that websites can provide. In their reviews of communication practices in hazard and emergency contexts, Henderson et al. (2022) and Coombs et al. (2024) identify websites as particularly valuable for delivering clear, practical, and comparatively detailed information. In contrast to social media, which have character and format limitations, websites can accommodate comprehensive guidance, explanatory content, and links to additional support resources (Coombs et al., 2024). This finding is supported by two heat-related channel-specific studies (social media and websites), both of which highlight the limitations that platform design creates on message depth (Olson et al., 2023; Tetzlaff et al., 2025a).

Tetzlaff et al. (2025a) offer a useful illustration of how channels with differing capacities can be combined. Although the study focused on Environment and Climate Change Canada’s national heat-health alert system, outside the scope of this review, and did not include behavioural outcome data, it provides a useful and transferable example of cross-channel design. It shows how concise messaging can be paired with web-based resources to extend depth.

Layered communication in Canada’s heat-health messaging system

To help educate the public during heat events, Health Canada and Environment and Climate Change Canada (ECCC) distribute heat-health messaging through national weather warning messages. Because these messages must be concise and suitable for a national audience, they face inherent challenges in providing sufficient detail or tailoring for specific risk groups.

To address this, Health Canada and the ECCC implemented a layered communication design in which the brevity required by the alert format was mitigated by hyperlinks directing readers to Health Canada’s website for more detailed, context-specific advice. The alerts provided short, actionable statements (e.g., reminders to “stay hydrated”), while the linked webpages elaborated on these actions, offered more detailed practical guidance, and included additional materials tailored for specific populations, illustrating the broader principle that websites can act as ‘anchors’ for more detailed content within a layered communication system.

Some specifically caution that the advantages of websites can be offset by weaknesses in design, readability, and accessibility. For instance, websites can be text-heavy, outdated, or poorly structured, making it difficult for users to navigate and absorb key messages (Henderson et al., 2022; Tetzlaff et al., 2025b). Tetzlaff et al.’s (2025b) readability assessment of local authority heat-related web pages in Canada found that much of the online material was pitched at a level too complex for the general public to understand. These barriers can also discourage repeat visits and reduce the visibility and usability of essential health advice.

These findings emphasise that ongoing investment in digital infrastructure and a sustained focus on accessibility are essential to maximise their benefits. At the same time, while websites remain valuable for providing detailed reference material, they should not be relied upon as the sole vehicle for inclusive health messaging. Public bodies must also recognise uneven digital access when designing communication strategies, ensuring that information reaches those who need it most and reflects communities’ preferred sources of information.

Social media platforms

Social media platforms (e.g., X, Instagram) are increasingly used to disseminate information about adverse weather and health risks and are now an established yet still-evolving component of this communication landscape (Henderson et al., 2022; McIntyre et al., 2019; Vu et al., 2019). Some organisations, for example the Red Cross and YMCA, are taking the lead in social media, disaster preparedness and health adaptation. They offer speed, immediacy, and potential for interactive engagement (McIntyre et al., 2019).

Social media use is highest among younger demographics (British Red Cross, 2023; Olson et al., 2023), creating opportunities to reach audiences that may not typically engage with more traditional channels such as broadcast or print media. However, as with websites, access and audience reach are uneven. Olson et al.’s (2023) study of heat-risk communication on Twitter in the United States for example specifies that only around 7% of Twitter users were aged 65 or older, limiting the platform’s direct reach to those most vulnerable to extreme heat. Nonetheless, the authors note that such channels could still play an indirect role by reaching younger caregivers and family members who may act as intermediaries for at-risk older adults.

Social media platforms have structural constraints, such as character limits, that can make it difficult to convey detailed information (Coombs et al., 2024; Olson et al., 2023; Tetzlaff et al. 2025a). Indeed, Olson et al. (2023) acknowledge this limitation within their broader argument that to persuade people to act, messaging needs to convey additional kinds of information (for example, justifying why a behaviour is recommended), as highlighted in the previous chapter. They therefore suggest using images, infographics, and ‘threaded’ messages to expand content. This design logic mirrors the layered communication approach illustrated by Tetzlaff et al. (2025a), where prioritisation i.e. focusing on essential, actionable advice, and cross-linking to web-based material was used to offset these limitations. This principle is directly applicable to social media practice, where posts can link to more detailed resources, use visual elements to enhance comprehension, and tailor messaging for different audiences.

Our stakeholder engagement provides examples of how these channels operate in practice across national, regional, and local contexts in Scotland.

Discussions we had with organisations in Dumfries and Galloway highlighted how different parts of Scotland’s communication infrastructure function together across scales. Locally, the Grow Well app delivered through Healthzone is widely used and trusted by parents, has been used for messaging around storms, with potential to extend information to other weather events.

Early years organisations we spoke to also make use of national resources such as Parent Club, viewed as a reliable source of advice to share with families, and of social media platforms like Facebook to communicate with parents, though there is uncertainty about how effective these are. Participants in our stakeholder engagement activities also pointed to hyperlocal channels, such as the “Edinburgh Minute” community news board, which frequently shares weather warnings within neighbourhood networks.

These discussions also highlighted the practical constraints that shape channel use. Digital-only dissemination is often unavoidable due to considerations around costs of producing printed leaflets or posters.

Digital resources like the NHS Inform webpages on summer health and heat safety were valued for being concise, accessible, and easy to navigate, offering short prompts, bullet-pointed guidance, and links to further information.

Social and community networks

A parallel layer of communication operates through community-embedded routes. These include both formal intermediaries, such as carers, doctors, and other healthcare professionals, local civil society organisations, community or faith leaders, schools, and social landlords, and informal networks of friends, neighbours, peers, and family members who exchange information through everyday interactions and ‘word of mouth’ (British Red Cross, 2023; Coombs et al., 2024; Forsyth et al., 2023; Health Canada, 2020; McIntyre et al., 2019; McLoughlin et al., 2023; VanderMolen et al., 2022; Williams et al., 2019).

The contribution of community-embedded routes lies in how they activate mechanisms that can influence behaviour: credibility and trust; amplification and reach; and relevance.

First, as discussed in Chapter 5, trust shapes whether advice is perceived as credible. Trusted figures include official or expert institutions, such as meteorological agencies (e.g. the Met Office), climate scientists, public health bodies, and weather forecasters (McLoughlin et al., 2023). However, local or community-based organisations and intermediaries, such as healthcare staff, community leaders, and faith organisations, are often trusted because of familiarity, accessibility, and ongoing relationships (Health Canada, 2020; McIntyre et al., 2019; McLoughlin et al., 2023; VanderMolen et al., 2022). Fathollahzadeh et al. (2023) describe this as the product of long-term credibility and perceived reliability. Williams et al. (2019), for example, found that carers and healthcare staff were often the primary conduits of heat-health information for older adults. These figures are perceived as credible and knowledgeable, which increases the likelihood that messages and recommended actions will be believed and acted upon (Coombs et al., 2024; Health Canada, 2020; McIntyre et al., 2019; Tan et al., 2024; VanderMolen et al., 2022).

Organisations representing older adults and those with long-term health conditions we spoke to as part of our engagement activities highlighted that the person who disseminates the public health messaging is also important, not just the message being given. They described that the person giving advice needs to be trusted, and co-produce messages with the communities they’re trying to reach.

Chapter 5 also highlighted the role of social norms in shaping protective behaviour. Community networks, which also include peers, friends, family, and neighbours, provide one of the main mechanisms through which these influences operate in practice. Forsyth et al.’s review of barriers to flood communication (2023), for example, notes that “the most powerful preparedness spokespersons are not government agencies or nongovernment organisations but simply other community members who have prepared” (p. 122). McLoughlin et al.’s review of determinants of heat-health behaviours (2023) and Tan et al.’s review of motivational factors influencing responses to mixed hazards (2024), including floods, further observe that trusted organisations can reinforce these social influences by modelling and endorsing protective behaviours within the community.

These findings resonate with insights from our stakeholder engagement discussions and build directly on the patterns highlighted in Chapter 5 regarding boys’ and young men’s low risk perception during hot weather. While these young men often dismiss formal messaging about sun exposure or dehydration, staff from a youth organisation noted that they were more receptive when safety guidance was shared informally by adults they knew and trusted, especially when those adults modelled the behaviours themselves, such as applying sunscreen.

Second, and relatedly, intermediaries enhance effectiveness by extending reach and raising awareness while reinforcing and validating ‘official’ information (McLoughlin et al., 2023). This amplification capacity can ensure that information reaches people who might otherwise be missed, either because they are less engaged with formal or digital media, or because some may distrust ‘official’ sources (British Red Cross, 2023; Coombs et al., 2024; McIntyre et al., 2019; VanderMolen et al., 2022).

Some international evidence shows intermediary networks can bridge gaps in reach and awareness. McLoughlin et al. (2023) found that mobile nurse outreach effectively delivered heat-health advice to older adults in Austria, helping close awareness gaps among vulnerable groups. VanderMolen et al. (2022) reported that low heat risk awareness was common among those with multiple vulnerabilities, such as age, limited education, or social isolation, and noted that community organisations are well placed to address these gaps. Both studies conclude that communication can be more effective through intermediaries with established contacts than direct outreach. Weitkamp et al.’s UK-based participatory research on challenges of communicating drought risk to the public (2020) reaches a similar conclusion (with a focus on water use). In the UK, because drought is seen as remote (‘drought happens elsewhere’) and inconsistent with lived experience, it creates ‘psychological distancing’ that reduces its perceived relevance. The study suggests that intermediary groups with emotional or experiential ties to water and the environment can help bridge this gap by acting as spokespeople or ‘multipliers’, extending message reach and resonance.

Insights from our stakeholder engagement activities reflect these patterns, highlighting how intermediaries can also convey information in culturally relevant ways, for example, using faith as an ‘entry point’.

Organisations working with diverse communities emphasised the central role of religious institutions (mosques and gurdwaras) can act as information hubs, reaching people across generations, including older adults who may have limited English proficiency or digital access. Trusted faith and community leaders can communicate public health information in culturally relevant and meaningful ways, for example by embedding it in religious teachings.

Third, community networks, who bring knowledge of needs and target audiences and local areas, can enhance personal relevance (Coombs et al., 2024; Health Canada, 2020; McLoughlin et al., 2023; VanderMolen et al., 2022; Weitkamp et al., 2020) through their ability to adapt public health guidance to lived realities, making it accessible and actionable by tailoring advice to people’s specific needs and circumstances, factors repeatedly identified as prerequisites for behavioural change.

This is because community networks can also provide unique opportunities for face-to-face or two-way exchanges, which allow individuals to ask questions, clarify advice, and relate general guidance to their lived experience. VanderMolen et al. (2022) illustrate how such dialogic exchanges increase comprehension and awareness of risk and heat-protective behaviours, their perceived relevance and confidence to act. These findings are consistent with several evidence reviews exploring the effectiveness of public- health disaster and extreme weather communication beyond heat (e.g. floods), which highlight that interactive, relational communication outperforms one-way information transfer for these reasons (Coombs et al., 2024; Henderson et al., 2022; McIntyre et al., 2019).

An example from our stakeholder engagement discussions illustrates this mechanism.

An organisation working with diverse communities runs interactive sessions that use discussion and guided questions to raise awareness of climate and adverse-weather risks in the Scottish context. This is because while many recognise the impacts of adverse weather (for example, flooding or drought) in their home countries, they may not realise that these events can and do occur in Scotland. By using real incidents as discussion prompts and encouraging people to talk through how they might respond, these sessions deepen understanding of adverse weather risks and make protective actions feel more concrete.

Two heat-focused studies emphasise that these actors can benefit from guidance and support to perform their roles effectively. Based on qualitative research involving community leaders, health workers, and representatives from public and third-sector organisations, VanderMolen et al. (2022) highlight that these intermediaries are part of established communication networks and outreach efforts. While well-positioned to convey public health messages, participants pointed out the need for training and expert input to equip them with the knowledge and confidence to educate their communities and train others. Similarly, McLoughlin et al. (2023) mention the potential of building capacity among diverse communicators, such as weather presenters, journalists, and community educators. They cite existing initiatives such as the Climate Matters programme in the U.S., which offers targeted training and resources, and UK initiatives such as the Women’s Institute, which has trained its members in heat risk communication.

Community networks are therefore conceptualised not as substitutes for formal channels, but as complementary components of a diversified communication strategy, where multi-channel delivery emerges as an important feature of communication effectiveness (British Red Cross, 2023; Coombs et al., 2024; Fathollahzadeh et al., 2023; Forsyth et al., 2023; Health Canada, 2020; Henderson et al., 2022; McIntyre et al., 2019; VanderMolen et al., 2022; Vu et al., 2019; Weitkamp et al., 2020).

This also points to the importance of consistency across message senders. Weitkamp et al., (2020) provide a practical illustration of contradictory guidance in relation to drought, where water companies may advise the public to conserve water while public health bodies simultaneously urge people to drink plenty of fluids (as drought is likely associated with a heatwave), highlighting a need for “careful management of the message” (p.842). Other studies also point out that contradictory information may undermine credibility and trust, create confusion, and weaken engagement with protective advice (Coombs et al., 2024; Fathollahzadeh et al., 2023; Forsyth et al; Health Canada, 2020).

Features of effective communication channels

The evidence presented in this chapter highlights that different types of communication channels (traditional, digital, and community-based) have different strengths and characteristics. These underpin the following overarching features of effective communication that emerge consistently across the literature:

• 
  No single channel is sufficient on its own. Maximising reach and accessibility requires diversifying channels, blending ‘traditional’ and digital media, and including community networks to maximise exposure to information.
  
• 
  Consistency across channels and senders is important. Conflicting messages can erode public trust, create confusion, and reduce compliance.
  
• 
  Communication strategies must be tailored with attention to equity of access, accounting for variations in digital connectivity, literacy, language, and cultural context.
  
• 
  Trust in the source increases message effectiveness. Messages are more likely to be acted upon when they come from credible, relatable, and trusted communicators.
  

Beyond broad cross-cutting features, below are channel-specific considerations presented in this section:

• 
  Traditional channels such as broadcast media and print materials remain valuable for disseminating information. Given their wide reach and continued use, some studies recommend that public health agencies strengthen collaboration with media outlets and intentionally use a mix of broadcast and print formats to maximise coverage.
  
• 
  Websites are widely used sources of information, while social media platforms are increasingly used to disseminate adverse-weather and health information. However, access, engagement, and audience reach remain uneven across population groups. They bring distinct strengths and design requirements. Websites can act as reference points, and their strength lies in their ability to provide clear and relatively detailed information. To make the most of them, attention should be given to content clarity, accessibility and usability. Poor design, inaccessible formats, or out of date content can reduce engagement. Social media can provide speed and visibility, reaching younger demographics particularly. Although it has structural limitations (e.g. limited characters), these can also be offset by layered communication, where brief posts link to more comprehensive resources. Infographics, videos, and visual aids can improve clarity and appeal.
  
• 
  Social and community networks can extend reach, improve comprehension, increase perceived relevance, and build confidence in recommended actions, particularly among groups considered to be at greater risk and/or less likely to engage with ‘official’ sources.
  

Links to wider evidence

We find that effective public health communication on adverse weather is well aligned with disaster risk communication and the risk perception literature generally (Fathollahzadeh et al, 2023; Speilhofer et al., 2020).

Stead et al. (2019) explored the use of media to communicate public health messages in six health topic areas (alcohol, diet, illicit drugs, physical activity, sexual and reproductive health and tobacco). The authors found that, depending on the topic area, mass media campaigns can influence knowledge, attitudes and beliefs, lead people to seek help and change behaviour (physical activity topic only). In line with our findings, this systematic review also found that targeting messages can be effective.

They also found some evidence that negative or ‘hard-hitting’ messages, as well as those aiming to shift social norms, may lead to behaviour change. There was also some evidence that both positive and negative messages can be effective, depending on the topic. Our rapid review suggests that the effectiveness of such messages related to adverse weather is more nuanced. For example, evoking emotions needs to be accompanied by actionable guidance; in relation to social norms, some studies suggest that messages which emphasise what others do or approve of can help normalise protective behaviours.

Reflecting the different characteristics of weather and the six health topics Stead et al. investigated, they found that “campaigns that run for longer and are more intensive (with people exposed to them more often, for example) are likely to be more effective, based on evidence from tobacco and sexual health campaigns in particular”. For communicating health risks of extreme weather events, and heat in particular, our findings also stress temporal proximity to an adverse weather event, the need to adjust messaging accordingly and repetition.

Conclusions

The evidence base on the effectiveness of public health communication for adverse weather events is limited. Only three studies identified in this review were designed to measure behavioural and health outcomes in ways that allow causal inference. All three were related to heat and specifically designed to target vulnerable groups (older adults and those with chronic conditions). The evidence suggests that public health communication can contribute to behaviour change.

The larger body of evidence we reviewed looks at how people respond to public health messages in real-world settings; for example whether they notice messages, remember advice, report changing (or intending to change) their behaviour. They also explore the factors that influence whether they act or intend to act. Across these studies, findings suggest that changes tend to be modest and not consistently observed among those considered most vulnerable, who may not be reached by public health messages or do not act on them. The pathway towards behaviour change is therefore non-linear and shaped by a range of individual and contextual factors.

The two main explanations around which there is broad alignment in the literature are:

• 
  People (in particular older people) do not like to see themselves as vulnerable, hence do not accept that they need to change behaviour.
  
• 
  People need to believe that the recommended actions are effective (response efficacy) and achievable (self-efficacy) to adopt them. They also need to believe that their actions can make a difference.
  

Other reasons include: not remembering or understanding the message; positive emotional responses evoked by mentioning of weather events (in the UK especially heat); practical barriers to implementing recommended actions.

Evidence from the wider risk perception literature shows that direct experience of a weather event, especially if negative and recent, shapes people’s perceived risk/sense of vulnerability and action, often more powerfully than information alone. Social influences (norms and interpersonal interactions) shape an individual’s adaptive behaviour, especially when people feel they have control. However, socio-demographic and socio-economic factors do not reliably predict how people perceive weather related health risk and their behaviour responses as these factors interact with psychological and contextual mediators.

The literature points to the importance of designing communications with attention to the contextual and individual factors that shape behavioural responses.

Effective messages tend to share several common features:

• 
  Practicality supports uptake. Effective messages are often action-focused, specific and feasible, using language that feels relevant and understandable to intended audiences. Clear steps, explained in straightforward terms and supported where appropriate by visuals or simple formats, help people understand both what to do and why it helps.
  
• 
  People engage with advice when they can interpret it, recall it, see why it matters, and recognise that the recommended actions fit their circumstances: messages that explain why an action is recommended appear to support people in assessing its value, while recognition of financial, physical, or practical constraints is associated with higher perceived realism.
  
• 
  Relevance and clarity shape how messages land. Tailoring content to different audiences and using plain, inclusive language — while avoiding labels that many at-risk individuals do not identify with — is also associated with greater relevance and engagement as it increases understanding and resonance.
  

Effectiveness of adverse-weather communication depends as much on how messages travel as on what they say. We did not identify studies that have tested the causal impact of different communication channels on attitudinal or behavioural outcomes, which reflects a gap in the evidence base. There is more consistent evidence regarding the types of channels used to disseminate adverse-weather information, patterns of access and preference, and their strengths and limitations. This includes reflections drawn from behavioural studies around what may make channels effective.

Three overarching conclusions stand out:

• 
  Different channels play different roles, and no single route reaches everyone.
  
  
  Traditional broadcast and print media still provide the widest reach; digital platforms offer speed and detail but do not engage all groups; and community and social networks can add trust, credibility, and opportunities for dialogue. Effective communication draws on these complementary strengths rather than relying on a single medium.
  
• 
  Trust and relevance shape how messages are received. People are more likely to pay attention and act when information comes from sources they recognise and rely on -whether national institutions, local organisations, or familiar community figures. Consistency across channels and senders helps maintain credibility and avoids confusion.
  
• 
  Equity of access affects exposure and response. Not everyone encounters information in the same way. Differences in digital access, literacy, language, and social support influence who hears a message and how they interpret it. Combining mass-reach channels with community-embedded routes can help ensure that those most at risk are not missed.
  

Future research

Research on public health communication is limited for weather events beyond heat and for vulnerable groups other than older adults e.g. young people, whose behaviour changes could yield long-term benefits. Few studies robustly evaluate messaging beyond self-reports or participatory planning, and author-devised messages are rarely user-tested. Comparative evidence on how people access information and the outcomes of different communication channels is also lacking. The role of misinformation or disinformation in shaping public responses to adverse weather is an important area of concern, particularly in the context of social media, and we note it as an area for further exploration.

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Appendices

1. 
   Research methodology
   

This study was delivered in two main phases. Phase 1 consisted of a Rapid Evidence Review (RER), which identified, assessed, and synthesised existing evidence on public-health communication and behavioural responses to adverse weather events (heat, cold, flooding, and drought). Building on Phase 1, Phase 2 consisted of an engagement phase involving interviews and workshops with key stakeholders.

This Appendix describes the detailed methodology for each phase.

Phase 1: Rapid Evidence Review: overview

The RER is a pragmatic and streamlined literature review method designed to collect and synthesise the best available evidence to support decision-making in a timely way (Devane et al. 2024). While RERs are not as comprehensive as systematic reviews, both approaches share robust, replicable and transparent methodologies. The key advantage of the RER approach lies in its pragmatism, making it particularly suitable for producing policy-relevant insights within short timeframes. We describe the stages of the review in the next sections.

Inception and scoping

The inception and scoping phase began with three scoping interviews with people with expert insight on our research questions. These interviews deepened our understanding of the policy context within which this research is situated.

Next, we developed search terms and a set of primary inclusion and exclusion criteria to guide the evidence search process. We included studies relating to the four weather events in scope (heat, cold, flooding, and drought) and prioritised those that focused on Scotland and the wider UK, along with comparable countries, defined here as high-income nations with institutional capacity for public health communication, broadly similar exposure to climate-related weather risks, or comparable temperate climates. These included North America, Western and Northern Europe, Australia, and New Zealand. We included only publications in English from between 2015 and 2025. We selected the starting point of 2015 to balance breadth and relevance within the constraints of a rapid review methodology. The date range reflects the growing research focus on climate resilience over the past decade, while ensuring the volume of literature remained manageable and timely for synthesis.

We then agreed secondary criteria and piloted the search to guide the literature screening process. The criteria were designed to assess both relevance and quality, capturing geographic fit, attention to health outcomes, inclusion of messaging examples, alignment with phases of the disaster-management cycle (preparedness, response, recovery) and study quality.

Formal search, longlisting and screening

The formal search proceeded in two waves. The first covered three bibliographic databases—Web of Science, ProQuest, and PubMed—using the refined search strings developed during inception. We applied the primary criteria to screen titles and remove clearly non-relevant items. We applied the secondary criteria at abstract and full-text stages. The second wave consisted of targeted searches for grey literature using Google and Google Scholar to address evidence gaps.

The final sample comprised 32 studies: 26 peer-reviewed articles and six grey literature reports. Most items focused on heat (n = 20), with a comparatively smaller number addressing both heat and cold (n = 2), drought (n = 4), floods (n = 2), multiple hazards (n = 4), which included heat and / or floods alongside other extreme weather events that were out of scope. In terms of geographic coverage, studies covered the UK (9) followed by the USA (5), Canada (4) and Australia (2). Evidence syntheses generally drew on broader international evidence.

We retained two literature items that fell outside the predefined geographic range. One study, from Japan, was included because it provided robust outcome data on a communications intervention. The second, focused on Central and Eastern Europe, was included due to its relevance to drought-related communication – a drought communication guide developed by a network of organisations from multiple countries, and based on available literature and relevant evidence.

Appendix C contains the full list of documents included in the review.

Data extraction and synthesis

We extracted information from each literature item using a structured template developed in Microsoft Word (Appendix B). The template drew on established frameworks for effective disaster risk communication and risk perception (Fathollahzadeh et al., 2023; Spielhofer et al., 2020) and was adapted to reflect the specific research questions for this study. Each member of the research team piloted the template to ensure consistency and fitness for purpose.

We organised the extracted data in MAXQDA, a qualitative analysis software package, and undertook thematic coding and synthesis, which we supplemented with data from the engagement phase (section 10.3 below).

Rapid Evidence Review: detailed approach

Following established principles, we conducted the RER in four main stages: (1) search strategy and piloting (conducted as part of the project’s scoping and inception); (2) longlisting; (3) screening and shortlisting; (4) extraction and synthesis.

Stage 1: Search strategy and piloting

This stage took place during the project’s inception. It involved developing search strings, inclusion and exclusion criteria, and piloting of search terms across selected databases. Initially, the plan was to search two databases (PubMed and ProQuest) alongside Google/Google Scholar. However, piloting showed that open-web searches generated an unmanageable volume of ‘hits’. Consequently, we slightly re-oriented our approach to include a third database (Web of Science) and to separate the process into two waves: peer-reviewed literature searches; and targeted grey-literature searches conducted at a later stage to fill evidence gaps. This refinement enabled a more efficient approach without compromising the feasibility of screening within a rapid review timeframe.

For research questions 1 and 2, we developed search terms using combinations of keywords across four core conceptual domains: weather events, communication, health outcomes, and effectiveness. To enhance the search design, we used SciSpace GPT, an AI-based research tool, to identify additional synonyms and related terms, which were incorporated into the final search strings. Although emergency alerts / warning systems were not within the formal scope of the review, we retained these terms in the search strategy to avoid restricting the evidence base and to capture studies that might offer transferable insights for public health communication more broadly. We then used the second-stage screening process to identify and retain studies that contained findings relevant to wider communication practice. Table 1 illustrates the resulting set of search terms.

Table 1: Questions 1 and 2 search terms

The terms were combined using Boolean operators (AND/OR) and adapted for each database. An example ProQuest search string for heat-related studies was structured as follows: (“heatwave” OR “heat wave” OR “extreme heat” OR “extreme heat events” OR “high temperatures”) AND (“risk communication” OR “public health communication” OR “public health warning*” OR “emergency alert *” OR “risk messag*”) AND (“health risks” OR “heat-related illness” OR “public health impact” OR “public health outcome*”).

Searches targeted terms in titles and abstracts, ensuring that generic terms such as “extreme weather” or “adverse weather” were also captured. Additional variants were therefore unnecessary.

For research question 3, we applied a more streamlined search. Given the size and maturity of the literature on factors influencing risk perception and behaviour in disasters, the search was designed to capture the strongest available evidence.

Table 2: Question 3 search terms

Inclusion and exclusion criteria

We established a two-tiered set of primary and secondary criteria to guide the search and screening process. The primary criteria were designed to ensure that initial retrieval was relevant to the study’s focus, while the secondary criteria were applied during the abstract and full-text review stages to assess relevance and quality in greater depth. These are shown in Table 3 below.

Primary criteria defined the parameters of relevance across four domains:

• 
  Weather event type: studies addressing heat, cold, flooding, or drought.
  
• 
  Geographic scope: we prioritised studies focusing on Scotland and the wider UK, alongside research from comparable international contexts, defined as high-income countries with institutional capacity for public health communication, broadly similar exposure to climate-related weather risks, or temperate climates. These were: North America, Western and Northern Europe, Australia, and New Zealand.
  
• 
  Language: English only.
  
• 
  Publication period: 2015–2025. We selected the starting point of 2015 to balance breadth and relevance within the constraints of a rapid review methodology. The date range reflects the growing research focus on climate resilience over the past decade, while ensuring the volume of literature remained manageable and timely for synthesis.
  

Where database functionality permitted, we embedded some of these parameters (language and publication date) directly into the search filters to ensure precision and relevance from the outset. These same criteria were then used to exclude clearly out-of-scope titles (for example, papers on unrelated hazards).

We developed secondary criteria to screen abstracts and full-texts. These captured both substantive relevance (how well the study aligned with the research aims and scope) and quality (how robustly the evidence was generated or reported). To support consistency and transparency, each record was assigned a numerical score for each criterion (0 = absent; 1 = partially present; 2 = fully present), producing a weighted, transparent system for prioritising inclusion. Records with the highest cumulative scores were retained for synthesis. Geography was included again among the secondary criteria to allow prioritisation of studies conducted in Scotland or the wider UK.

Table 3: Inclusion and exclusion criteria

Quality appraisal

Our appraisal approach reflected the potentially diverse nature of the evidence base, encompassing both ‘intervention-focused’ studies (for example, those describing or testing a messaging strategy or design, or a communications campaign) and studies that may draw conclusions about the nature and approach to messaging based on empirical data or evidence reviews. All studies were assessed using a core set of quality criteria, covering:

• 
  Conceptual framing: whether the study articulated a clear conceptual framework or research question, and whether conclusions were grounded in empirical evidence.
  
• 
  Methodological transparency: whether the research design and methods were described, and whether data sources were clearly cited or traceable
  
• 
  Validity: whether the study demonstrated internal validity (e.g. consideration of alternative causes or limitations) and external validity (e.g. generalisability to other contexts or populations).
  

For ‘intervention-focused’ studies, these criteria were supplemented with an Evidence Effectiveness Framework (Cullen, J et al., 2019) – a Standards of Evidence tool developed by the research team to assess the strength of evidence in emerging policy areas where few interventions have been evaluated through experimental methods such as RCTs. The framework, derived from a review of 19 major standards-of-evidence scales, applies tight criteria and categorises interventions as innovative, effective, or replicable. For instance, replicability denotes that an intervention (such as a campaign) has been robustly evaluated or has demonstrated transferable results in comparable contexts.

We scored each quality component (conceptual framing, methodological transparency, validity) using the scoring system described above (0–2 scale) and calculated the average quality score. This was then combined with relevance criteria (e.g. geography, presence of messaging, link to the disaster management cycle) to form the total weighted score used in shortlisting.

Piloting

We conducted a piloting stage to test the sensitivity and precision of the draft search strings across the originally selected databases — PubMed, ProQuest, and Google/Google Scholar. The pilot returned a high number of low-relevance results from Google searches, which informed our decision to reorient the search strategy: we added Web of Science as a third database to strengthen coverage of peer-reviewed literature and limited the use of Google to targeted grey-literature searches at a later stage (during abstract and full-text review).

During this piloting phase, we retained all records that appeared potentially relevant. Several of these early items were grey-literature reports, which we kept on a provisional list for consideration in the subsequent targeted grey-literature search.

Piloting also confirmed the need to adapt search syntaxes and Boolean combinations for each database to ensure optimal retrieval of relevant records, as platforms varied in how they indexed and parsed search terms.

As an additional quality assurance step, we used Medical Subject Headings (MeSH) on Demand in PubMed to confirm that our search strategy was retrieving all relevant studies. The tool analyses the abstract and keywords of an article to identify similar papers and their associated key terms. We applied this process to several relevant papers identified during the pilot search across weather events to check whether additional studies were retrieved, and to identify any additional terms that could refine our search strings. This exercise confirmed that our search strategy captured the core evidence base.

Stage 2: Formal search and longlisting

We conducted the formal search using the finalised search strings across the three databases. All records were then exported into a bibliographic spreadsheet in Microsoft Excel, containing key fields (authors, year, title, source, and abstract). This enabled the review team to carry out title screening (described in more detail below) directly within the spreadsheet to remove studies clearly out of scope according to the primary inclusion criteria. We also developed an additional structured matrix specifically for this evidence review to include both the primary and secondary criteria. All records that passed title screening were transferred into the matrix and also exported into Zotero reference-management software, which provided the foundation for subsequent abstract and full-text screening and scoring. This structure ensured a consistent, transparent, and auditable workflow, allowing reviewers to record inclusion decisions and quality scores systematically.

Stage 3: Screening and shortlisting

The screening followed a three-tier process based on titles, abstracts, and full texts against inclusion and exclusion criteria.

• 
  Tier 1 – Title screening: focused on removing items that databases captured but were clearly out of scope. Examples included records outside the four weather events in scope (such as COVID-19), or that focused on general climate adaptation policy or environmental health studies. If a title did not make its relevance clear, the paper was retained for Abstract screening rather than excluded.
  
• 
  Tier 2 – Abstract screening: we reviewed and scored Abstracts against the inclusion and exclusion criteria. Records that appeared ambiguous were either flagged for second-reviewer discussion or retained for full-text screening to avoid premature exclusion. For example, studies mentioning alert systems but potentially containing relevant communication insights or learning were retained for full-text screening.
  

Tier 3 – Full-text screening: The remaining items were reviewed in more depth looking at the full texts, again against the secondary inclusion criteria.

In parallel, we conducted a targeted second-wave search for grey literature. This built on the provisional list of items identified during the piloting phase.

Two reviewers conducted all screening activities independently. We held regular meetings to discuss and resolve any discrepancies, with final adjudication resolved through discussion and consensus and quality-assurance oversight, provided by the project director. Studies achieving the highest cumulative scores were retained for data extraction.

Throughout the process, we maintained flexibility in applying the scoring framework, recognising that few studies offered formal evaluations of communication interventions. For example, we retained high-quality studies conducted in other regions (e.g. Japan) where evidence offered strong empirical insights, and we also included studies focused on alert or warning systems (which were out of the scope of the research) where the communication elements demonstrated transferable lessons for public-health messaging.

Selection of sources of evidence

Using 15 search strings adapted for three databases (Web of Science, PubMed, ProQuest), we screened 3,568 titles. Following the initial title screening, 3,225 records were excluded.

This left 343 records sought for retrieval. Within this group, 127 duplicate records were removed, and the 68 relevant reports identified during the pilot searches were added, resulting in a total of 284 records that were assessed at the abstract screening stage. A total of 48 studies proceeded to full-text screening, during which 20 were excluded. This process yielded 28 peer-reviewed studies included in the synthesis.

The targeted grey-literature search identified 13 candidate reports. After appraisal, five were retained. We excluded items that were outside the date range (2013), two (on flooding and drought) because they duplicated material already captured through peer-reviewed studies, and others (mostly heat-related) because stronger evidence had already been included. The final sample comprised 32 studies (26 peer-reviewed articles and six grey-literature reports) taken forward for extraction and synthesis. The full process is illustrated in the PRISMA flow diagram below.

Figure 1 PRISMA flow diagram

Data extraction and synthesis

We extracted information from each item using a structured template developed in Microsoft Word (see Appendix B). The template was organised around the study’s three research questions and drew on established knowledge on the components of effective communication and on the factors influencing risk perception and behaviour, as summarised in existing frameworks (e.g. Fathollahzadeh et al., 2023; Spielhofer et al., 2020). This provided the conceptual framework for the analytical process.

To ensure consistency and fitness for purpose, each member of the research team piloted the template using three literature items that reflected slightly different types of evidence (an evidence review, an empirical study, and an evaluation of an intervention). We made minor refinements to harmonise interpretation of fields, accommodate the diversity of the studies, and to streamline the information.

We then imported the extraction templates into MAXQDA, a qualitative analysis software that enabled systematic coding and synthesis of themes across the evidence base in line with the three research questions.

Engagement Phase

Phase 2: Engagement

The aim of this phase was to engage with organisations representing groups particularly at risk of negative health impacts of adverse weather in Scotland and / or hard to reach. We carried out five workshops and four interviews to explore barriers, motivators and enablers to engagement and participation in adverse weather health messaging.

Three workshops were with organisations representing parents / carers of young children under 5; ethnic minority communities; older adults and adults with particular health conditions.

Two workshops were place-based, focused on Glasgow Easterhouse and Dumfries and Galloway, designed to explore lived experiences of specific weather events, the kinds of messaging people had seen or received, and what types of communication worked best in their context. We selected Dumfries due to its frequent flooding, linked to proximity to the River Nith. We selected Glasgow as an urban setting for insights on heat and cold, where high social vulnerability (for example related to poor housing) can limit people’s ability to prepare for and respond to temperature extremes.

Four one-to-one semi-structured interviews were carried out with representatives of specific communities. These were the Gypsy Traveller community; organisations working with minoritised communities; place-based experience of flooding (Dumfries and Galloway); and Water Safety Scotland (flooding, extreme heat and cold).

The insights gathering process for Phase 2 was conducted from September and October 2025. Through online interactive workshops and interviews we explored the barriers, motivators, and enablers shaping engagement with adverse-weather messaging.

We conducted:

• 
  3 organisational workshops (Early Years, Health/Age, Diverse Communities)
  
• 
  2 place-based workshops (Glasgow Easterhouse, Dumfries and Galloway)
  
• 
  4 semi-structured interviews
  

We spoke to:

• 
  22 people
  
• 
  13 organisations
  
• 
  3 communities
  

Organisation list:

• Early Years
  • Home-Start Edinburgh
    
  • One Parent Families Scotland
    
  • Scottish Infant Feeding Network
    
• Safety
  • Adaptations Team, Scottish Government
    
  • Scottish Fire and Rescue Service
    
  • Water Safety Scotland
    
• Health/Age
  • Asthma and Lung UK
    
  • British Red Cross
    
  • Age Scotland
    
• Diverse Communities
  • CEMVO Scotland
    
  • Networking Key Services
    
  • Article 12
    
• Place-based
  • Pavillion
    
  • 
    Community councils in Dumfries and Galloway
    

Workshop Guide and Materials

The template workshop guide used for each workshop is as follows. Note that each workshop was tailored to fit the adverse weather events spoken about, and public health materials discussed, depending on the population group spoken to. Each workshop was between an hour and an hour and a half.

Workshop guide – Organisational workshops

Workshop guide – Place-based workshops

Interview Guide

Find below the interview guide template used for semi-structured interviews. Interviews were around 45 minutes long, conducted online.

Introduction

Thank you for taking the time to participate in this interview. Before we jump into the interview I’ll give you a little more information on the project. We are working with ClimateXChange, who are Scotland’s centre of expertise on climate change, to figure out the best ways to communicate nationally about healthy behaviours before, during, and after adverse weather. This involves both the content of the message and the communication channels used.

The findings of this research will help to support delivery of the Public Health Scotland’s Adverse Weather and Health Plan, which sets out how Public Health Scotland, with support from the Scottish Government and working in partnership with key stakeholders, will help to protect people’s health from adverse weather-related harm.

Now when we talk about adverse weather, we mean extreme weather, which is becoming more common with climate change. For the purpose of this project we’re focusing on extreme heat, cold, flooding, and drought. And while extreme weather affects everybody, we know that there are certain groups of people that can be more at-risk than others.

This is why we’ve reached out to you – [insert rationale here]

GAIN CONSENT TO RECORD THE SESSION

Tell me about a recent flood, drought, heatwave, or bout of extreme cold that impacted your population group. Did they see the event as a risk, or did they feel prepared? Do you know what their reaction was afterwards? Were they influenced into action, and how?

**Note: If they haven’t experienced any of these four, broaden to any adverse weather event

Related to the weather example you’ve just told me, which communication channels do you believe were most effective for reaching your population group, and why? Which do you think were least effective?

How does your organisation approach their comms when it comes to relaying a public health message around adverse weather?

Prompts: what considerations / principles inform their approach to:

• • 
    content (tone, clarity, type of information, quantity, language considerations)
    
  • 
    format (visuals etc).
    
  • 
    any differences by weather event?
    
  • 
    differences by stage (before, during, after a weather event)
    

Thinking about content, what do you think works best when relaying an effective public health message? Why?

What do you do with your messaging to reach and engage the people that you represent/the people you want to see this messaging?

Prompts: highlight what is communicated (message design, content) and how (e.g. channel, dissemination strategy), and when (before a weather event, during, after)

What are the main barriers your population group face in engaging with health messages about weather-related risks?

What are the key enablers that help your population group engage with and act on health messages about adverse weather?

As a result of the struggles/challenges/barriers, have you seen an increase in awareness/knowledge/motivation to change their attitudes or behaviours in the face of an adverse weather event?

Research scope

The research was designed to examine how communication can support protective health behaviours in response to adverse weather events (heat, cold, flooding, and drought). The review focused on what is communicated, how messages are delivered, and the factors that influence whether people engage with public health messaging.

As a result, some related issues were outside the scope of this research. For example, we did not examine the role of misinformation or disinformation in shaping public responses to adverse weather and this did not emerge as a prominent theme in the literature identified with the help of our search criteria. However, this is an important area of concern, particularly in the context of social media, and we note it as an area for further exploration. For readers seeking additional insight, relevant developments can be found in the Scottish Health Information Integrity Strategy 2025-2030 (Scottish Government, 2025).

1. 
   Rapid Evidence Review: Extraction template
   

1. 
   List of literature items included in the review
   

How to cite this publication:

Iacopini, G; Junge, K; Drabble, D; Owen, C Tombazzi, A. (2026) ‘Effective public health messaging for adverse weather events’, ClimateXChange. https://doi.org/10.7488/era/7268

© The University of Edinburgh, 2026
Prepared by The Tavistock Institute of Human Relations and Innovation Unit on behalf of ClimateXChange, The University of Edinburgh. All rights reserved.

While every effort is made to ensure the information in this report is accurate as at the date of the report, no legal responsibility is accepted for any errors, omissions or misleading statements. The views expressed represent those of the author(s), and do not necessarily represent those of the host institutions or funders.

This work was supported by the Rural and Environment Science and Analytical Services Division of the Scottish Government (CoE – CXC).

ClimateXChange

Edinburgh Climate Change Institute

High School Yards

Edinburgh EH1 1LZ

+44 (0) 131 651 4783

info@climatexchange.org.uk

www.climatexchange.org.uk

Average temperatures in Scotland are rising and climate change is contributing to more frequent episodes of heat and cold, flooding and drought, all of which have implications for public health and health inequalities.  

Scotland has a comprehensive policy framework to address the health impacts of climate change including the Public Health Scotland (PHS) Adverse Weather and Health Plan 2024–27 (AWHP), published in July 2024. The plan sets out PHS’s commitment to working with partners to help mitigate, prepare for, and respond to the potential health risks associated with adverse weather, recognising these risks fall unequally across the population. The Plan covers the following weather-related hazards, with a significant impact on health: heat, cold, flooding, and drought. 

This research combines a rapid evidence review and stakeholder engagement to examine effective approaches for delivering persuasive messages that support protective health behaviours during adverse weather events. It focuses on four weather events within the AWHP: periods of hot and cold weather, flooding and drought.   

Key findings 

• Evidence on the effectiveness of public health communication disseminated for adverse weather is limited. Few studies directly link communication to health outcomes, with most focusing on intermediate outcomes such as awareness, knowledge, and behaviour change or intentions to act. 
• Rather than reflecting a simple linear relationship between information and action, this evidence points to a more complex picture in which behavioural responses are shaped by multiple factors that communicators need to consider. 

The research identified these principles for effective messaging including what channels are most effective: 

• Make guidance actionable, specific, and directive – people need to believe they are capable of the action and that it will be effective 
• Ensure ‘message relevance’: people need to see themselves in the message and believe the message is for them. This includes being mindful of how people self-identify and supporting people to personalise the risk.  
• Consider people’s emotional responses to certain weather events as some e.g. heat and drought can attract positive emotions. However, counteracting these with negative framings is insufficient unless combined with efficacy information.  
• Communication should be tailored to different audiences, recognising variation in language, literacy, housing conditions, income, geography, and other factors that shape how people access, interpret, and act on information   
• Clear, inclusive, and accessible language can improve engagement. Visuals, infographics, storytelling, and culturally relevant communication approaches can further support understanding and make messages feel more personally relevant. 
• Timing relevant to the weather event is important. 
• Traditional channels (broadcast and print media) remain widely used and valued, especially among groups less likely to engage online.  
• Digital channels, including websites and social media, are important components of adverse-weather communication strategies. Websites are widely used sources of information, while social media platforms are increasingly used to disseminate adverse-weather and health information and may help reach audiences less likely to engage with traditional media, particularly younger groups. However, access, engagement, and audience reach are uneven.  
• Formal and informal community networks are particularly important for those who may not engage with formal or digital channels. Their effectiveness is underpinned by credibility and trust; amplification and reach; and relevance and personalisation. 

For further information, please read the full report. You can also read a detailed report of insights taken from the engagement phase of this project in Annex 1.

If you require the report or annex in an alternative format, such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

Display image for this page: Adobe Stoc, irontrybex

Research completed: March 2026

DOI: https://doi.org/10.7488/era/7237

Executive summary

Background and aims

Reducing greenhouse gas emissions by encouraging a reduction in single occupant car journeys is part of Scotland’s path to net zero. People and Place is Transport Scotland’s primary active and sustainable travel behaviour change programme (Transport Scotland, 2024, 2025a). In this report, active travel means walking, wheeling and cycling for everyday journeys. Sustainable travel is broader. It includes active travel, public transport, shared transport and other lower-carbon ways of travelling instead of driving alone. The programme sits within Scotland’s wider effort to reduce car dependence and make short everyday trips easier to take by active or shared modes (Scottish Government, 2020; Transport Scotland, 2020, 2022, 2023).

People and Place now funds a wide range of activity through the seven Regional Transport Partnerships (RTP) and local authority direct awards. For 2024-25 the RTP programme was organised around four themes: Schools and Young People; Workplaces; Accessibility and Inclusion; and Capacity and Capability Building. From 2025-26 the remit was widened to include sustainable travel interventions (Transport Scotland, 2024, 2025a). In practice this now covers work with schools and workplaces, access-to-bikes schemes, inclusion measures, travel behaviour campaigns, cycle parking, small physical improvements, shared mobility and links to public transport. That breadth is one of the programme’s strengths because it allows delivery to reflect local need. It also makes monitoring harder, because a single measure cannot capture these different mechanisms of change equally well.

Our work evaluates how the impacts of modal shift to active transport in the People and Place programme can be robustly measured, given the scale and breadth of active travel behavioural change interventions delivered by the programme.

This report draws together the project findings and proposes a practical monitoring and evaluation framework. It does not try to produce a final quantified estimate of programme impact. Instead, it sets out what the current evidence base can already support, where the main gaps lie, and what changes would make future reporting more useful.

Key findings

• 
  Scotland already has strong active travel evidence, but it is spread across surveys, counters, project returns and administrative sources. These sources are useful together, but they are not interchangeable. National surveys can show broad travel trends, while counters can show what happened on particular routes.
  
• 
  The most valuable national building blocks are clear. The Scottish Household Survey gives the best picture of travel behaviour and mode share across Scotland, while the Cycling Scotland counter network provides the strongest continuous evidence on cycling volumes. Each answers only part of the People and Place question, so the system can harness their potential through jointly using the data in a complementary way.
  
• 
  The biggest challenge of the current system is to link what was delivered and how change is recorded. Interview evidence suggests that some projects are still reported through free-form responses, inconsistent metrics or ad hoc requests. This makes it hard to compare areas or build a reliable national picture from local delivery.
  
• 
  A universal project reporting form would prove unwieldy – the emerging evidence points to a typology-based approach, where different interventions each have a small set of tailored minimum metrics.
  
• 
  Mixed methods are essential. Ministers and programme managers need comparable numbers, but they also need short structured qualitative evidence that explains who was reached, what barriers shifted, what did not work and whether change looks likely to last.
  
• 
  Wider outcomes such as health, emissions and wellbeing should be modelled only after core reporting is stable.
  

Recommendations

• 
  Transport Scotland should formalise a small core dataset by intervention type and issue it in workable, iterative manner going forward. This is not a wholesale redesign. Several RTPs are already moving in this direction and the main need now is to align approaches.
  
• 
  The first technical priority should be a national intervention register, with location, date, intervention type, delivery scale and target group recorded for every funded project.
  
• 
  Reporting should be digital and structured. A short template with fixed fields and drop-down options would reduce free-form returns and make quality assurance much easier.
  
• 
  Every project should submit a short qualitative return alongside the core numbers. This could use a common case-study format with prompts on reach, inclusion, barriers, unintended effects and lessons for future delivery.
  
• 
  Transport Scotland should build a layered evidence model around existing national assets, especially the Scottish Household Survey, Cycling Scotland counters, school travel data and project returns. The main challenge is not collecting entirely new national data, but linking existing sources in a consistent way.
  
• 
  Implementation should be phased. Phase 1 is shared architecture and templates. Phase 2 is data linkage and interpretation. Phase 3 is wider outcome modelling and targeted deep dives.
  

Glossary / Abbreviations table

Introduction

Policy and programme context

People and Place sits within a clear policy chain. Scotland’s transport and climate policy now expects fewer short trips to be taken by single-occupancy car and more to be made by walking, wheeling, cycling, shared transport and public transport. That expectation runs from the Climate Change Plan update and the car kilometre reduction route map through to National Transport Strategy 2 and the Cycling Framework for Active Travel (Scottish Government, 2020; Transport Scotland, 2020, 2022, 2023).

That policy role explains why the programme is deliberately broad. Some projects work through schools or workplaces, while some widen access to cycles or e-bikes. Others rely on community organisations, with projects also linking active travel to shared transport or public transport. This diversity is a strength of the programme, but it also means that no single indicator or metric can fairly describe every intervention. The official programme themes should therefore remain distinct from the monitoring typologies proposed later in this report. Those typologies are analytical groupings for evidence purposes rather than replacements for the programme’s policy categories (Transport Scotland, 2024, 2025a; People and Place project team, 2026d).

Scope of this report

Our work evaluates how the impacts of modal shift to active transport in the People and Place programme can be robustly measured. It therefore focuses on framework design, sequencing and delivery implications. The question is not only which indicators are conceptually desirable, but which ones RTPs, local authorities and delivery partners can use consistently within funding and staffing constraints.

Approach

Evidence used

This report is based on existing evidence already assembled for the commission. That material includes the bid and scoping documents, the evidence mapping workbook, the literature review, synthesis notes, slide decks and stakeholder interviews, alongside the earlier Cycling Scotland report on methods for monitoring cycle use (Cycling Scotland, 2013; People and Place project team, 2025a, 2025b, 2025c, 2026a, 2026b, 2026c, 2026d).

These materials were used for different purposes. The evidence mapping and quality appraisal show what data already exists and where the main gaps sit. The literature review helps distinguish between behavioural outcomes and wider determinants of change. The interviews show which reporting approaches are feasible in practice. The slide decks are useful because they capture the project’s emerging design logic and implementation pathway (People and Place project team, 2025b, 2025c, 2026a, 2026b, 2026c, 2026d).

Stakeholder interviews

Stakeholder interviews were used to understand needs and delivery reality as well as testing feasibility. They included conversations across RTPs, delivery partners, Cycling Scotland and other relevant organisations involved in monitoring, programme management and delivery. The interviews were not designed as a representative survey of the whole active travel sector. They are best read as feasibility evidence on what can be implemented proportionately within a live programme (People and Place project team, 2026d). Fourteen stakeholder interviews were conducted across Transport Scotland teams, delivery partners, third parties and all seven RTPs. Appendix C contains details of the semi-structured interview scripts, which focussed on data availability, utility and aspirations to inform evidence mapping and methodological recommendations.

The interviews were especially useful for three reasons. First, they showed where reporting burden sits in practice, especially in small teams. Second, they surfaced examples of emerging good practice, such as project-type-specific templates, digital forms and shorter school-based question sets. Third, they made clear that stakeholders want more structure from the centre, but not a rigid one-size-fits-all model (People and Place project team, 2026d). They also highlighted the importance of a mixed-methods approach to combine qualitative and quantitative information.

Analytical approach

Our work is a secondary synthesis of published information, supplemented by findings from stakeholder interviews. It compares the different project materials, looks for recurring findings across them, and places those findings inside a practical policy framework.

This approach has limits. The materials were produced at different points in the project and not all datasets are equally mature. The programme itself is also still early in delivery, so some monitoring systems are being built while the programme is already running. The diverse and place-based nature of projects also results in variation across monitoring and evaluation needs and capacities, which is an important consideration in formulating methodologies.

Findings

A rich but fragmented evidence base

Scotland does not lack active travel data. It currently lacks a cohesive architecture that joins together national surveys, counter data, school travel data, project returns and local evaluation in a way that supports programme learning. Different datasets were created for different purposes, use different geographies and timeframes, and often sit with different organisations (Cycling Scotland, 2013; People and Place project team, 2025c, 2026a).

That fragmentation matters because People and Place is asked to answer several questions at once. Ministers may want to know whether the programme is contributing to reduced car dependence, RTPs may want to know which delivery models are working best, and local delivery partners may want to know whether a specific project reached the people it was designed for. The diversity of programme delivery underscores the need to combine complimentary data-based approaches based on their strengths and weaknesses in a future monitoring and evaluation framework (Table 1) (People and Place project team, 2025c, 2026a).

The evidence shows that Scotland already has a set of complementary sources. The task is to use them together and to be explicit about which question each one can answer (Cycling Scotland, 2013; People and Place project team, 2025c, 2026a).

Table 1 – Main evidence sources and the questions they are best placed to answer.

Harnessing potential across datasets

Across the material reviewed, one conclusion is consistent: the Scottish Household Survey remains the best single source for understanding mode share and travel behaviour at national scale. It is broad, long-running and methodologically strong, through the use of random sampling collection methods and annual reporting. Due to these strengths, this dataset has potential to form the basis for active travel indicator monitoring. (People and Place project team, 2025c, 2026a; Transport Scotland, 2025b).

A second national asset is the Cycling Scotland monitoring network and associated traffic survey work. These data are valuable for a different reason. They are sensitive to change over time and can show how cycle use changes on particular routes, corridors or local networks. They are therefore especially useful for spotting local movement in places where interventions happened. A further nuance from the evidence mapping is that this part of the system remains strongest for cycling and, in some places, walking. Comparable continuous evidence for wheeling and broader sustainable travel is much thinner and more uneven (Cycling Scotland, 2013, n.d.; People and Place project team, 2025c, 2026a).

The problem is that these strengths are different. A counter can show that cycling increased on a route after a project, but it cannot show whether overall car use decreased across the wider area. A national survey can show Scotland-wide behaviour change, but it is not granular enough to track most individual projects. School travel data adds a further useful layer, but only for school journeys. The framework should treat these sources as complementary layers, not as alternatives. This is reflected in the strategy currently underway in Transport Scotland’s People and Place team for the new financial year (People and Place project team, 2025c, 2026a; Sustrans, 2025; Transport Scotland, 2025b). The combination of these mutually-reinforcing datasets with local contextual information, for example from small area census data, can help inform the development of typology-based monitoring and evaluation approaches. This could take various forms, including an interactive online dashboard which is currently being discussed within Transport Scotland (People and Place project team, 2025c).

Alignment of monitoring needs and expectations

The key challenge to address in the current system is the mismatch between reporting requirements, delivery timescales and organisational capacity. Interviewees described a first programme year in which delivery was often prioritised over evaluation design, which is understandable in a new funding environment but limits understanding of impact (People and Place project team, 2026d).

Several practical examples recur. Some projects were reported through free-form templates that asked broad questions rather than a stable set of defined fields. In some cases, cycle parking or small infrastructure was delivered near the end of the funding year, then an evaluation return was requested almost immediately afterwards. In others, new quantitative requests arrived late in the year even though that data had not been collected from the start. These are not minor operational issues. They shape what evidence can exist at all (People and Place project team, 2026d).

The burden also falls unevenly. A small grant to a community group cannot be expected to produce the same quantity or quality of data as a large multi-partner programme. Small RTPs and local authorities reported that monitoring competes with day-to-day programme management, partner support and governance reporting. That makes proportionate expectations essential (People and Place project team, 2026d).

At the same time, some RTPs are already improving their own systems. Examples include digital final evaluation forms, shorter question sets for schools, and typology-based frameworks. This is important because it suggests the programme is not starting from zero. The next step is building on progress via alignment and consolidation (People and Place project team, 2026d).

A minimum shared framework

The interviews point in a clear direction. Stakeholders do not want a return to completely ad hoc local reporting, but they also do not believe that one standard form can work across every project. What they want is a short shared minimum requirement, with flexibility above that floor (People and Place project team, 2026d).

A typology-based framework is the most promising route. Under this model, projects are first grouped by what they are trying to do and how they work. A school travel initiative, an access-to-bikes scheme, a workplace programme, a gamified behaviour change campaign and a cycle parking measure would not all report exactly the same fields. They would report a small set of fields that make sense for their intervention type, with some common metadata across all projects (People and Place project team, 2026c, 2026d).

This approach is already visible in current practice. Some RTPs have developed six to eight project categories and require only one or two essential datasets for each category, while allowing additional evidence where local capacity exists. Another advantage is interpretability. When a reader sees data from one category, they know what change mechanism the metric is supposed to represent (People and Place project team, 2026d).

Mixed methods and phased approaches

A more structured quantitative framework will improve reporting, but it will not remove the need for qualitative evidence. People and Place often works through confidence, inclusion, convenience and habit formation. Those processes matter because they help explain why an intervention may look different across places and groups, even when headline outputs appear similar (People and Place project team, 2025b, 2026d).

Structured qualitative evidence can take various forms. In this context, it refers to a short, consistent template. For example, each project could provide a brief account of who was reached, what barrier was addressed, what changed, what did not work, and whether effects appear likely to last. This is more useful than long free-text case studies because it supports targeted comparisons without losing context (People and Place project team, 2026d).

The same logic applies to wider outcomes such as health, emissions and wellbeing. These are clearly relevant to the programme, but they should not be loaded onto frontline delivery reporting before the core architecture is stable. It is more realistic to phase them in later, using observed programme activity and national data as inputs to careful modelling. That would improve interpretation, but it would still be decision support rather than direct proof of causality (People and Place project team, 2025a, 2026b, 2026c).

Recommended monitoring and evaluation framework

Design principles

The framework proposed here is built around five design principles drawn from the project evidence and stakeholder interviews (People and Place project team, 2025c, 2026c, 2026d).

• 
  Metrics should follow intervention type rather than assume one universal template.
  
• 
  Monitoring should show contribution without overstating impact or assuming attribution.
  
• 
  Context should sit beside outputs so that place differences are visible.
  
• 
  Reporting and monitoring should be proportionate to project scale and organisational capacity.
  
• 
  Wider societal outcome modelling should be staged and transparent.
  

Intervention typologies and minimum metrics

The first practical decision is typology. The programme needs a stable shortlist of intervention types used consistently across funding, delivery and reporting, with exact labels able to be co-produced or refined with RTPs. The official People and Place programme themes should remain in place for programme management. The typologies proposed here are analytical groupings for monitoring and evaluation, designed to link similar interventions to similar evidence requirements rather than to replace the programme’s policy categories (Transport Scotland, 2024, 2025a; People and Place project team, 2026d).

A workable starting point is six broad types: active schools, active workplaces, access to bikes and inclusion, community behaviour change, shared mobility and integration, and small capital or supporting measures. This is a workable starting point for evidence purposes because it translates the programme’s broad delivery model into categories that can reasonably share minimum metrics and similar interpretive logic, including under the wider sustainable travel remit introduced for 2025-26 (Transport Scotland, 2025a; People and Place project team, 2026c, 2026d).

This is not a call for over-engineering. The aim is a small, stable set of essential fields for each type, plus optional additional evidence where capacity exists. That is a manageable change and RTPs are already close to it in practice (People and Place project team, 2026d).

Table 2 – Illustrative intervention typologies and the type of evidence each one should prioritise.

The minimum national architecture

Once typologies are agreed, the national framework should be built around a minimum set of shared components. These are the pieces Transport Scotland needs in every case, regardless of local delivery model (People and Place project team, 2026c, 2026d).

This architecture does not require a whole new national data system in year one. The relatively easy steps are agreeing definitions, issuing consistent templates and setting up digital returns. The more demanding steps are data linkage, quality assurance and shared interpretation. That difference matters because it means reform can be sequenced rather than treated as a single large change (People and Place project team, 2026b, 2026c, 2026d).

There is also an important consideration here regarding multi-level governance. There are two phases to reporting and monitoring impact; the first is projects reporting back RTPs and LAs, with the second being RTPs and LAs reporting back to TS. Agreeing these steps and definitions at different levels of governance is crucial to maintain proportionality and a utilisable framework. The dynamicism and frequency of reporting can be tailored across governance levels as well as across project types.

Table 3 – Suggested minimum national architecture for People and Place monitoring.

A layered evidence approach

The evidence supports a layered approach rather than a single-metric model. Each layer answers a different question (People and Place project team, 2026b, 2026c).

This layered structure, or logic model, helps avoid a common problem in programme reporting. Outputs are often presented as though they were outcomes, and outcomes are sometimes presented as though they were proven impacts. A layered model is more robust because it separates delivery records, observed signals of change, contextual interpretation and modelled wider outcomes (People and Place project team, 2026b, 2026c).

For Transport Scotland, Layer 1 and Layer 2 are feasible under current operations. Much of this information already exists, even if it is not yet standardised. Layer 3 is achievable where existing national or local datasets can be used intelligently. Layer 4 should be developed more cautiously, because it depends on appraisal assumptions and should support interpretation rather than claim attribution (People and Place project team, 2025a, 2026a, 2026c).

Table 4 – A layered evidence model for programme-level interpretation.

A phased implementation pathway

The framework can be introduced sequentially rather than through wholesale reform. That matters because delivery partners are already working within live funding cycles (People and Place project team, 2026b, 2026c, 2026d).

This sequence keeps early demands realistic. It does not ask delivery partners to provide challenging, resource-intensive data up front, and it lets Transport Scotland concentrate first on the enabling steps that will make later analysis more credible (People and Place project team, 2026b, 2026c, 2026d).

Table 5 – A phased route from fragmented reporting to structured programme evaluation.

Recommendations for Transport Scotland

Adopt a typology-based core framework.

Transport Scotland should replace the idea of a universal reporting form with a nationally agreed typology-based framework. This is not a large conceptual departure from current practice. RTPs are already moving in this direction, and the main task is to converge around a stable minimum rather than invent something wholly new (People and Place project team, 2026c, 2026d).

Publish the minimum dataset and definitions as soon as possible.

The dataset should be stable for the full year and accompanied by plain-English definitions, metadata rules and deadlines. This would solve one of the most persistent problems raised in interviews: data requests arriving too late or changing after projects are already underway (People and Place project team, 2026d).

Build a geotagged and time-stamped intervention register.

Every funded project should have a consistent spatial and temporal record. This is the missing link between local delivery and national analysis. It is a medium-effort change because it requires agreed identifiers, simple mapping rules and basic quality assurance, but it does not require advanced modelling to begin with. Done well, it would make later linkage work with counters, school travel data and contextual variables much easier. It would strengthen contribution analysis, but geotagging alone would not demonstrate causality (People and Place project team, 2026b, 2026c).

Make mixed-methods reporting standard, not optional.

Alongside the core numbers, each project should submit a short qualitative return using structured prompts. A sensible template would ask who was reached, what barrier was addressed, what changed, what remained difficult, and what was learned. This is proportionate, useful and widely aligned with what interviewees said they need (People and Place project team, 2026d).

Harness the strengths of existing national datasets for long-term programme interpretation.

Transport Scotland should treat the Scottish Household Survey, Cycling Scotland counters, school travel data and selected contextual datasets as the stable national foundation. This is feasible because those assets already exist. The improvement needed is not to build them from scratch, but to connect project reporting to them more deliberately and interpret them more systematically (Cycling Scotland, n.d.; People and Place project team, 2025c, 2026a; Sustrans, 2025; Transport Scotland, 2025b).

Provide shared implementation support.

A light touch support offer is needed if the framework is to work consistently. This should include templates, a definitions guide, example completed returns, training for new staff and a named route for analytical queries. Interview evidence suggests that this would remove friction more effectively than asking each region to solve the same problems independently (People and Place project team, 2026d).

Phase wider societal outcome modelling and longitudinal deep dives.

Health, emissions, wellbeing and social value analysis should be introduced once Phase 1 reporting is stable. These indicators could be tailored to include specific policy targets related to active travel, such as reductions in child poverty or modal shift (People and Place project team, 2026c). A small number of deep-dive case areas should then be commissioned to test assumptions about behavioural change and wider impacts. That would build a stronger evidence base over time without turning routine monitoring into an unmanageable burden (People and Place project team, 2025a, 2026b, 2026c).

Conclusions

People and Place can be monitored effectively through a shared information architecture, through harmonising and harnessing pre-existing data and collection methods across Scotland. The evidence reviewed here points to a framework that is typology-based, layered and mixed-method. That framework would be more proportionate for delivery partners and more useful for national interpretation (People and Place project team, 2025c, 2026a, 2026d).

Scotland already has many of the ingredients required: robust national survey data, an expanding counter network, school travel data, local project intelligence and growing experience within RTPs. The priority now is to connect those ingredients more deliberately, simplify what is asked of delivery partners, and build wider outcome modelling only once the core reporting foundation is secure (Cycling Scotland, n.d.; People and Place project team, 2025c, 2026a, 2026d; Sustrans, 2025; Transport Scotland, 2025b).

Next steps

• 
  Agree the national intervention typology and minimum fields with RTPs and delivery partners.
  
• 
  Finalise digital templates, definitions and the reporting timetable before the next funding round.
  
• 
  Build the intervention register and assign governance and quality-assurance responsibilities.
  
• 
  Pilot observational linkage in a small number of areas using counters, school travel data and contextual baselines.
  
• 
  Identify candidate deep-dive case areas for later-phase validation and learning.
  

References

Cycling Scotland. (2013). Methods for monitoring cycle use [External report].

Cycling Scotland. (n.d.). Cycling Open Data portal. Retrieved March 16, 2026, from https://cycling.scot/knowledge-and-data/monitoring/sharing-data/open-data

People and Place project team. (2025a). Bid for People and Place active and sustainable travel programme: Options for monitoring and evaluation of modal shift [Unpublished internal project bid]. Edinburgh Climate Change Institute.

People and Place project team. (2025b). High-level literature review [Unpublished internal review]. Edinburgh Climate Change Institute.

People and Place project team. (2025c). Evidence mapping workbook [Unpublished internal workbook]. Edinburgh Climate Change Institute.

People and Place project team. (2026a). Summary of findings: Evidence mapping and quality appraisal [Unpublished internal summary]. Edinburgh Climate Change Institute.

People and Place project team. (2026b). Interim findings [Unpublished internal presentation]. Edinburgh Climate Change Institute.

People and Place project team. (2026c). Steering group update [Unpublished internal presentation]. Edinburgh Climate Change Institute.

People and Place project team. (2026d). Stakeholder interview transcripts [Unpublished internal transcripts]. Edinburgh Climate Change Institute.

Scottish Government. (2020). Securing a green recovery on a path to net zero: Climate change plan 2018-2032 – update. https://www.gov.scot/publications/securing-green-recovery-path-net-zero-update-climate-change-plan-20182032/

Sustrans. (2025). Hands Up Scotland Survey 2024: Overview. https://www.sustrans.org.uk/media/o3ndegzb/hands-up-scotland-survey-2024_overview.pdf

Transport Scotland. (2020). National Transport Strategy 2. https://www.transport.gov.scot/publication/national-transport-strategy-2/

Transport Scotland. (2022). A route map to achieve a 20 per cent reduction in car kilometres by 2030. https://www.transport.gov.scot/publication/a-route-map-to-achieve-a-20-per-cent-reduction-in-car-kilometres-by-2030/

Transport Scotland. (2023). Cycling Framework for Active Travel: A plan for everyday cycling. https://www.transport.gov.scot/publication/cycling-framework-for-active-travel-a-plan-for-everyday-cycling/

Transport Scotland. (2024). Bulletin – January 2024 – Active Travel Transformation. https://www.transport.gov.scot/progress-update/bulletin-january-2024-active-travel-transformation/

Transport Scotland. (2025a). Bulletin – June 2025 – Active Travel Transformation. https://www.transport.gov.scot/progress-update/bulletin-june-2025-active-travel-transformation/

Transport Scotland. (2025b). Transport and Travel in Scotland 2024. https://www.transport.gov.scot/publication/transport-and-travel-in-scotland-2024/

Appendices

1. 
   Illustrative minimum fields by intervention type
   

Table 7 provides an expanded starting point for discussion. It is deliberately practical rather than exhaustive. The purpose is to show the sort of fields that could form the minimum dataset, while keeping the burden on delivery partners proportionate (People and Place project team, 2026c, 2026d).

Table 7 – Expanded illustrative minimum fields by intervention type.

1. 
   Suggested short qualitative evidence template
   

A structured qualitative return should be short enough to complete quickly but specific enough to support synthesis. Devising a usable framework which minimises reporting burdens while capturing valuable outputs is the key challenge. This can be led by Transport Scotland and refined with RTPs and DPs. Table 8 shows a simple format that could sit alongside the quantitative return (People and Place project team, 2026d).

Table 8 – Suggested prompts for a short qualitative return.

1. 
   Semi-Structured Stakeholder Interview Questions
   

Introduction and Context

• 
  Introductions and project context
  
• 
  Explain where this interview feeds into project process
  
• 
  Highlight that confidentiality will be ensured – no quotes attributed personally, notes/recordings taken with permission.
  

Interview Structure and Core Questions

High-Level Background

1. 
   Could you briefly describe your role and involvement in active travel delivery or monitoring?
   
2. 
   What are your organisation’s current priorities or challenges around monitoring and evaluation of modal shift?
   

Existing Data

1. 
   What data sources does your organisation currently use to monitor active travel in general, or specific to walking and cycling?
   
2. 
   Which indicators are reported internally or externally (e.g., modal share, trip length, participation rates)?
   
3. 
   How reliable, useful or comprehensive do you find your current methods/datasets (spatially, temporally, or methodologically)?
   

(Prompt if needed: Are there any notable strengths, gaps, or inconsistencies?)

Data Collection and Integration

1. 
   How is monitoring data collected – for example, automated counters, surveys, app data, or local reporting from funded projects?
   
2. 
   Are there currently strategies for data integration across local authorities, RTPs, or delivery partners?
   
3. 
   Does your area/organisation have specific requirements/considerations around monitoring and evaluation?
   

Evaluation and Learning

1. 
   Are there examples of evaluations or monitoring approaches you’ve found particularly useful or effective?
   
2. 
   How do you currently use monitoring data – for example, for funding decisions, strategy, or reporting?
   
3. 
   How would you estimate your organisation’s access to analytical tools or staff with data expertise?”
   
4. 
   What capacity does your team have in terms of monitoring and evaluation? To what extent is this outsourced? What skillsets currently exist within the team regarding data collections/analysis/reporting?
   

Emissions and Co-Benefits Estimation

1. 
   What are your thoughts/experiences on the crossover between active travel interventions and emissions/co-benefits impacts? How connected do you see these outcomes?
   
2. 
   How, if at all, does your organisation currently evidence the contribution of active travel interventions to wider outcomes such as emissions reduction, health, or place quality, and where do you see the main evidence gaps?
   
3. 
   To what extent do you feel confident attributing wider co-benefits or emissions impacts to active travel interventions, as opposed to broader contextual or policy factors?
   
4. 
   How important do you view the symbiosis between these shared outcomes?
   
5. 
   At what stage of the design/implementation process, if any, does climatic or co-benefit related considerations emerge?
   

Forward Look

1. 
   Do you see future changes to current issues affecting Scotland’s active travel evidence base?
   
2. 
   Are there data or methods you think are underused (e.g., mobile data, community engagement, health data)?
   
3. 
   Is there anything you’d like to see from future evaluation frameworks or data tools developed through Transport Scotland or CXC?
   

Closing

Thanks and reminder of how their insights will feed into:

1. 
   The Step 1 evidence mapping
   
2. 
   Step 2 methodology mapping
   
3. 
   Step 3 emissions and co-benefits estimations
   

How to cite this publication:

Sudmant, A. and Higgins-Lavery, R. (2026) ‘People and Place Active and Sustainable Travel Programme: Options for Monitoring and Evaluation of Modal Shift’, ClimateXChange. https://doi.org/10.7488/era/7237

© The University of Edinburgh, 2026
Prepared by The University of Edinburgh on behalf of ClimateXChange, The University of Edinburgh. All rights reserved.

While every effort is made to ensure the information in this report is accurate as at the date of the report, no legal responsibility is accepted for any errors, omissions or misleading statements. The views expressed represent those of the author(s), and do not necessarily represent those of the host institutions or funders.

This work was supported by the Rural and Environment Science and Analytical Services Division of the Scottish Government (CoE – CXC).

ClimateXChange

Edinburgh Climate Change Institute

High School Yards

Edinburgh EH1 1LZ

+44 (0) 131 651 4783

info@climatexchange.org.uk

www.climatexchange.org.uk

Reducing greenhouse gas emissions by encouraging a reduction in single occupant car journeys is part of Scotland’s path to net zero. People and Place is Transport Scotland’s primary active and sustainable travel behaviour change programme.

People and Place funds a wide range of activity through the seven Regional Transport Partnerships (RTP) and direct funding to local authorities. The RTP programme covers work with schools and workplaces, access-to-bikes schemes, inclusion measures, travel behaviour campaigns, cycle parking, small physical improvements, shared mobility and links to public transport. That breadth is one of the programme’s strengths because it allows delivery to reflect local need. It also makes monitoring harder, because a single measure cannot capture these different mechanisms of change equally well.

This project examines how the impacts of shifting to active transport in the People and Place programme can be robustly measured, given the scale and breadth of active travel behavioural change interventions delivered by the programme.

This report draws together the project findings and proposes a practical monitoring and evaluation framework. It does not try to produce a final quantified estimate of programme impact. Instead, it sets out what the current evidence base can already support, where the main gaps lie, and what changes would make future reporting more useful.

Key findings

• Scotland already has strong active travel evidence, but it is spread across surveys, counters, project returns and administrative sources. These sources are useful together, but they are not interchangeable.
• The most valuable national building blocks are clear. The Scottish Household Survey gives the best picture of travel behaviour and mode share across Scotland, while the Cycling Scotland counter network provides the strongest continuous evidence on cycling volumes. Each answers only part of the People and Place question, so the system can harness their potential through jointly using the data in a complementary way.
• The biggest challenge of the current system is to link what was delivered and how change is recorded.
• A universal project reporting form would prove unwieldy – the emerging evidence points to a typology-based approach, where different interventions each have a small set of tailored minimum metrics.
• Mixed methods are essential. Ministers and programme managers need comparable numbers, but they also need short structured qualitative evidence that explains who was reached, what barriers shifted, what did not work and whether change looks likely to last.
• Wider outcomes such as health, emissions and wellbeing should be modelled only after core reporting is stable.

Recommendations 

• Transport Scotland should formalise a small core dataset by intervention type and issue it in workable, iterative manner going forward.
• The first technical priority should be a national intervention register, with location, date, intervention type, delivery scale and target group recorded for every funded project.

For further information, please read the full report.

If you require the report in an alternative format, such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

Scotland has 2.5 million occupied dwellings, accounting for 13% of our greenhouse gas emissions and around 30% of our energy use.  Creating a robust plan for decarbonising how we heat our buildings is one of the most complex challenges on the path to net zero.   Over two programmes, from 2016-2021 and in the current 2022-2027 period, ClimateXChange has commissioned over 40 studies relating to heat decarbonisation. They range from the application of heating technologies to the economic and social impacts of adopting low-carbon heating. This research has supported informed policy development and played a significant role in the evolution of the Scottish Government’s Heat in Buildings Strategy.  

Co-designed, policy-ready research 

Decarbonising heat in buildings requires multidimensional and cross-disciplinary insights and information in an accessible format to a range of audiences across policy, technical and installation, and the general population. CXC’s work has been crucial in helping the Scottish Government to navigate the significant technological and behavioural change challenges that decarbonising heating entails.   

CXC’s strength is our strong co-delivery process, providing co-designed research with timely delivery of robust, policy-ready and accessible outputs. We work closely with policy and analytical colleagues to develop the research specifications and access a wide pool of expertise through our procurement processes. Across more than 40 reports relating to heat decarbonisation, we have provided a combination of technical evidence and regulatory and behavioural insights to support the development of policy.   

Building a portfolio of multidimensional research 

We have responded to a range of research questions from policy teams with the aim of providing complimentary yet specific evidence for policy decisions relating to heat in buildings. This has included assessing the potential impacts on the housing market, considering the role of different funding options for clean heat solutions, reviewing lessons from policy development internationally, and understanding the technical complexities of adopting different technologies.  

Projects have also included reviewing the international research landscape around heat decarbonisation and translating findings into the Scottish-context. Evidence reviews have investigated how different countries are legislating for the heat transition, the potential need for flexibility in regulations, and potential routes for compliance.    

Technical research commissioned by CXC has considered topics such as opportunities for lower flow temperatures for domestic heating, the role of subscription models to pay for clean heating technologies, and how proposed legislation would affect island communities.    

Our projects have also included insights on how to communicate to and engage the public in the heat transition, and deliberative research on a fair distribution of costs and benefits.  

Supporting the development of a robust strategy 

Delivery of the Scottish Government’s Heat in Buildings policy has evolved since the publication of the first Heat in Buildings Strategy in 2021 in response to the complexities of such a significant transition. Throughout the development of decarbonisation plans, CXC research has helped Scottish Government to shape and adapt proposed regulations.   

The breadth and depth of our research output on heat in buildings policy has given policymakers an accessible evidence base that acknowledges the complexities involved in decarbonising heating. This allows for better informed decision-making across a range of interrelated issues.  

The policy teams that have worked with CXC on research commissions related to decarbonising heat in buildings have highlighted the impact access to policy-relevant research has had on policy development.   

“The portfolio of commissioned research through CXC has been a valuable resource to draw on in developing the Heat in Buildings Strategy. We have been able to access a wealth of evidence and research insight across a range of technology, economic and social issues – from questions on the potential use of hydrogen for heating to lessons from transition policy approaches in other countries. It would be very difficult to get this solid and accessible evidence base to inform heat in buildings policy without support from a centre like CXC.”

Former head of Heat Strategy at the Scottish Government, 2025

Three of our reports published in April 2025, covering the domestic housing market, leases in the non-domestic sector and lowering flow temperatures in Scotland’s homes, were highlighted in a submission from Cabinet Secretary for Net Zero and Energy to the First Minister and Deputy First Minister: 

“This research contributes to the HiBs knowledge base and has been used to directly inform development of our policy proposals. HiBs policy proposals support the delivery against the FM’s priority of tackling the climate emergency. These reports provide valuable insights into potential impacts that could result from the proposals set out within the HiBs Bill consultation and wider Heat in Buildings programme. These have been taken into account by officials to progress policy positions. The evidence provided by the reports highlights the complexities that are faced in finalising our policy positions to introduce regulations for clean heat and energy efficiency which aligns with our external communication to date, reenforcing the need for Ministers to carefully consider these issues.”

 Former Cabinet Secretary for Net Zero and Energy, 2025

The impact of the reports on informed policy decision-making was also acknowledged in a briefing for a Ministerial Statement from the same time: “The evidence from these projects has supported our decision to adopt a new approach to the Bill, which will provide flexibility in how we make the transition, in a way that is feasible and affordable to all.” 

Directly influencing plans

As well as informing the high-level policy process, CXC reports have input into specific Scottish Government plans and strategies.   

Our report on the potential impacts of regulation in the housing market influenced plans being developed on requirements for energy efficiency improvements. The qualitative analysis and stakeholder engagement in this project, in the absence of quantitative data, helped the Scottish Government to anticipate the suitability of regulations and adapt them accordingly.  

Research commissioned by CXC into heat networks including funding and finance models and the potential using waste heat sources contributed to the development of district heating plans and influenced the development of Local Heat and Energy Efficiency Strategies.  

Our report into new build developments across the Scottish Islands found they were already installing zero emissions technologies due to a lack of mains gas connection. This insight, and lessons on the adoption of electric heating technologies in island communities, contributed to the design of the New Build Heat Standard introduced in 2024.   

Maximising policy application 

Beyond these examples, Scottish Government policy teams recognise the important role CXC research has played helping them to navigate the challenges in developing and implementing regulations to decarbonise heat.  

“CXC has facilitated multiple important research projects on the heat transition for Scottish Government. These have helped us better understand how proposed heat and energy efficiency regulations might impact both domestic and non-domestic sectors here in Scotland. CXC’s ability to synthesise highly technical and specialist regulatory analysis to tight policy timelines, and their expertise in engaging and communicating research findings to specialist and non-specialist audiences, have been invaluable in this.” 

Senior Research Officer in OCEA, 2025 

Our review of international heat and energy efficiency policy has also informed parliamentary scrutiny as findings were discussed in a meeting of the Public Audit Committee in February 2024. It was noted that the project “has helped to inform [the Scottish Government’s] approach to its Heat in Buildings Strategy (HIBS) programme, including how it intends to use regulation to drive changes in how we heat our homes”. 

Supporting future development

The development of Scotland’s decarbonisation policies continues to be a complex process. We expect the CXC research to contribute to the development of the Heat in Buildings Strategy and Delivery Plan due to be published by the end of 2026. The strategy will set out the actions, for the Scottish Government and others, designed to decarbonise buildings by 2045. The draft Buildings (Heating and Energy Performance) and Heat Networks (Scotland) Bills are expected to be introduced to parliament following the Scottish elections in May 2026.  

Through informing and shaping policies that support decarbonising heat in buildings, our research and insights will impact on businesses and homeowners across Scotland. These impacts will include a range of health and socio-economic benefits such as better insulation and reduced fuel poverty and be realised as policies and engagement take effect during the coming years. 

Related projects

Housing market impacts from heating and energy efficiency regulations in Scotland

Assessing the impact of the Heat in Buildings Bill on leases in the non-domestic sector

Reductions in maximum flow temperatures in Scottish domestic heating

Providing flexibility in heat and energy efficiency regulations – personal circumstances

International heat and energy efficiency policy review

Zero emissions heating in new buildings across Scottish Islands

Funding and financing heat networks in Scotland 

Potential sources of waste heat for heat networks in Scotland 

All ClimateXChange reports related to decarbonising heat in buildings can be found on our published research page

Related policy documents

Heat in Buildings Bill correspondence: EIR release

Heat in Buildings Bill: consultation paper

Heat in Buildings Bill consultation strategic environmental assessment

New Build Heat Standard

Heat transition: public engagement strategic framework

Heat in Buildings Strategy – achieving net zero emissions in Scotland’s buildings 

Public Audit Committee: Decarbonising heat in homes 

Research completed: March 2026

DOI: https://doi.org/10.7488/era/7249

Executive summary

The Scottish Government has statutory commitments to achieve net zero and to eradicate fuel poverty. This study reviewed the existing evidence base on the benefits and trade-offs of installing energy efficiency measures alongside clean heat in Scottish homes. It also provides evidence to support the development of the Heat in Buildings Delivery Plan.

A fabric first approach, which prioritises maximising a building’s thermal performance through improved insulation, for example, has traditionally been advocated across the retrofit sector. Indeed, the Scottish Government’s Heat in Buildings Strategy supports such an approach to underpin the roll-out of low and zero emissions heating. However, energy efficiency improvements alone will not deliver net zero emissions. Many industry stakeholders argue that only basic fabric measures are required to enable cost-effective decarbonisation, when combined with clean heat upgrades. But it is also necessary to consider the wider impacts of retrofit and heating upgrades on health, wellbeing, and household finances.

Aims

This study aimed to ascertain whether there is consensus on an optimal balance between fabric efficiency and clean heat solutions for Scottish homes. The balance must deliver concurrently on the cross-sector agendas of net zero, fuel poverty, and public health.

The analysis was primarily carried out via a literature review. In addition, surveys were conducted with key stakeholders to explore health, wellbeing and socio-economic impacts. Recognising that data gaps were present in the existing literature, the study also proposes a brief for further modelling work to address these.

Findings

There is conflicting information on the desirable level of fabric performance for a home to be considered suitable for clean heat. Some studies look at a system’s capability to maintain a desired indoor temperature during the coldest expected weather conditions. Others consider running cost implications, with the aim of avoiding increased heating costs

compared to the existing home heating system. Studies found optimal solutions are often different in UK housing archetypes compared to Scottish ones. Climate and property characteristics of Scotland must be considered to fully understand efficiencies and costs.

Improving a home’s fabric can reduce peak heating loads and therefore help improve heating system efficiencies and reduce running costs. The literature also suggests other options to achieve cost effective clean heat given potential property constraints, including:

• radiator upgrades
• high-temperature heat pumps
• demand shifting using Time-of-Use tariffs
• self-generation of power via solar energy
• different heat pump systems (e.g. hybrid heat pumps or air to air heat pumps

The cost-effectiveness of measures will vary by tenure, and the viability of various options will depend on the circumstances:

• Owner-occupiers may prefer solutions with a better whole-life cost
• Renters may favour options that do not increase ongoing energy bills
• For others, minimising disruption or space loss may be a priority
• For social landlords, economies of scale may have the biggest influence

There has been limited exploration of the specific impact of the fabric versus clean heat balance on fuel poverty. No research appears to have assessed impacts following the

Scottish Government’s approach to assessing fuel poverty statistics. Retrofit also offers opportunities to improve household health and wellbeing, as well as tackling high energy bills and reducing fuel poverty risk. Many homes and households at risk of fuel poverty or with particular health needs may require more extensive retrofit measures.

Retrofit opportunities noted by stakeholders, included:

• using ‘trigger points’ for retrofit measures when other home upgrade or renovation
  works are undertaken can be more practical and cost-effective
• raising awareness of the health and comfort benefits of retrofit could be more
  motivational than carbon or cost arguments
• a stronger focus on commissioning and aftercare with new clean heat systems could
  improve system efficiencies and end user satisfaction and may negate the need for
  more extensive measures to deliver acceptable heating running costs

Recommendations

• Policies should remain flexible and avoid prescribing a single retrofit pathway across all homes.
• Those in fuel poverty, or significantly at-risk, should be supported with more extensive retrofit measures to reduce running costs and improve comfort.
• Therefore, a modelling exercise should be undertaken to investigate the extent of measures likely to be required to remove Scottish homes from fuel poverty (or at least close the gap) while decarbonising.

Glossary/Abbreviations table

Introduction

This study reviews the existing evidence base on the benefits and trade-offs of installing energy efficiency measures alongside clean heat in Scottish homes. The Scottish Government has statutory commitments to achieve net zero and to eradicate fuel poverty. This research examines trade-offs between fabric efficiency improvements and clean heat investments to support the development of policies addressing net zero, fuel poverty, and public health objectives. It aims to support a balanced, evidence-driven approach in the Heat in Buildings Delivery Plan.

Background and research scope

Emissions from houses will need to be reduced to contribute towards Scotland’s ‘net zero’ by 2045 target. This is required via the Climate Change (Emissions Reduction Targets) (Scotland) Act 2019. The Heat in Buildings Strategy (Scottish Government, 2021) sets the framework for decarbonising homes, outlining a pathway to eliminating direct emissions from homes by 2045. This includes improving fabric thermal efficiency to underpin the roll-out of clean heating and to address commitments made under the Fuel Poverty (Targets, Definition and Strategy) (Scotland) Act (2019). A Scottish household is in fuel poverty if:

• they need to spend more than 10% of their adjusted net income (after housing costs) on fuel to achieve a satisfactory heating regime, and
• the remaining income is insufficient to maintain an acceptable standard of living.

To support the delivery of the Strategy, the forthcoming Heat in Buildings Bill will set out laws on how buildings will be heated and meet required energy performance standards. The bill will place a focus on reducing costs for people alongside decarbonisation.

The independent Green Heat Finance Taskforce report (April 2025) stated that the cost of heating homes in Scotland is having a negative impact on health outcomes. It proposed that transforming how buildings are heated can deliver multiple social, economic and environmental benefits. Housing is linked to health in various ways, as set out in the ‘Healthy housing for Scotland’ briefing paper by Public Health Scotland (2021). This includes the impact of physical conditions such as damp and mould on ill health. It also highlights the impacts of fuel poverty and affordability on mental health. Policy decisions on approaches to housing retrofit can therefore have a significant impact on health and wellbeing. These factors will also need to be taken into consideration alongside net-zero and fuel poverty agendas.

The UK Government’s recently published Warm Homes Plan aims to improve energy efficiency in UK homes, reduce household energy bills and reduce fuel poverty. Specific retrofit grants outlined in the plan will apply only to England. Compared to previous initiatives, the Plan adopts a more technology-led approach, promoting clean heat technologies and electrification measures alongside insulation improvements. The Plan places less emphasis on extensive fabric retrofit measures such as solid wall insulation, citing cost and supply chain constraints.

The aim of this research is to ascertain whether there is consensus on an optimal balance between fabric efficiency and clean heat solutions for Scottish homes.

Scope: This study focusses primarily on the interrelationships and trade-offs between energy efficiency measures and clean heat. Other renewable energy sources (not related to space heating) were considered only where they were integral to the case being made for fabric or clean heat respectively. Heat networks were also out of scope for this study.

Methodology

The objectives of this study were primarily delivered via a literature review. In addition, a number of surveys were conducted with key stakeholders. These specifically explored the implications of the potential fabric/clean heat balance on health, wellbeing and socio-economic (HWS) impacts. Recognising that data gaps were present in the existing literature, the study also proposes a brief for further modelling work to address these. The approach to tasks is discussed further in Appendix A, with a brief summary given below.

Literature review: A desk-based evidence review sought information from academic articles and grey literature. A selection of initial search terms were used, followed by a cascade approach to identify further references cited in relevant articles. Inclusion/exclusion criteria were set, including a focus on domestic properties, material linking both energy efficiency and clean heat, prioritising experience of relevance to the Scotland stock. References to HWS effects were also identified alongside energy/net zero impacts.

Stakeholder interviews: Seven expert interviews were held to gather insights into wider HWS impacts of installing fabric and clean heat improvements from the perspective of different groups. These included representatives from third sector organisations, academic and independent research organisations with particular interests in fuel poverty and/or healthy homes. Most were specifically concerned with the situation in Scotland, while some represented a UK-wide view. An interview topic guide was developed that served as the basis for consistent semi-structured interviews. Common themes were identified and compared with the findings of the literature review.

Developing the scope of a future modelling project: Data gaps and recommendations emerging from the evidence review were collated. A workshop with Scottish Government officials informed recommendations for future modelling. Based on the feedback, the research team proposed modelling approaches to address these needs.

Characteristics of the Scottish housing stock

Data from the Scottish House Condition Survey (SHCS) indicates that there were 2.55 million occupied dwellings in Scotland in 2024 (Scottish Government, 2025a) (all data mentioned below is from SHCS 2024 unless otherwise referenced). These cover a diverse range of property types with varying characteristics. Key trends include:

• 56% of homes are rated EPC C or above (compared to 53% of homes in England, (ONS, 2025). Dwellings with lower energy efficiency (i.e. EPC bands F and G) are disproportionately represented in rural areas. It is recognised that retrofitting rural homes in Scotland often incurs a significant cost premium due to logistical challenges and property characteristics, such as age, size and construction.
  
• 28.7% of homes (732,000 households) were in fuel poverty in 2024, which occurred across all tenures. 14% (357,000) were in extreme fuel poverty. 42% of fuel-poor homes used electricity for heating. Households in remote/rural areas have higher rates of fuel poverty. The high proportion of low energy efficiency homes in such areas noted above will be a driver for this.
  
• Approximately 23% of Scottish homes are social rented properties (Scottish Government, 2026) (compared to 16% in England (MHCLG, 2025b). Scottish Government regulates standards for social homes, so has significant influence over this sector. Social housing offers opportunities for economies of scale in retrofit, where landlords often address multiple, often similar, properties. Cost reduction opportunities could potentially influence the optimal choice of measures for homes, since optimality will be sensitive to capital costs. 49% of fuel-poor homes were in the social rented sector.
  
• Tenements make up 23% of the Scottish housing stock, of which 30% were built before 1919 (of the type common in Edinburgh and Glasgow). However, 70% of tenements are rated EPC bands A, B, or C, suggesting most are relatively energy efficient. Combined with other types of flats, they represent 35% of Scottish dwellings. By comparison, flats and apartments make up only approximately 21% of English dwellings (MHCLG, 2025a). Tenements and other multi-unit blocks with shared ownership can present challenges to traditional fabric retrofit due to the need to secure collective consent for works. However, the high rate of flats and tenements offers greater potential for communal systems and heat networks as clean heat solutions, if challenges relating to the coordination of works can be overcome.
  
• Approximately 13% of Scottish homes are privately rented properties (Scottish Government, 2026). 37% of households in the private rented sector (PRS) were in fuel poverty. 40% of homes in the sector were built before 1919 (approximately 128,000 homes). Due to their age, these homes will typically be of solid wall construction, for which installing wall insulation is more technically challenging and can be costly. Some may therefore be exempt from having to undertake such measures under proposed future Minimum Energy Efficiency Standards (MEES) for the PRS. This may be on grounds of negative impacts on the fabric or structure, or due to upgrade works exceeding the cost cap (Scottish Government, 2025b). Cheaper, alternative measures in support of decarbonisation and mitigating fuel poverty may therefore be required for this portion of the private rented sector.

Strategies for competing objectives

The ‘fabric first’ approach to retrofit

A fabric first approach prioritises improving the thermal performance of the building fabric before deploying low carbon heating systems or renewable technologies. The logic is that this sequencing reduces the heating system capacity and subsequent energy demand that needs to be met by these systems. Supporters of this approach note that it offers the best chance of achieving energy cost reductions for households and reducing fuel poverty (Existing Homes Alliance Scotland, 2019; National Energy Action, 2024). This method is well established, widely recognised within the retrofit sector and firmly integrated into building standards. The Scottish Government’s Heat in Buildings Strategy supports a fabric first approach to underpin the roll-out of low and zero emissions heating (Scottish Government, 2021).

Main benefits/opportunities of this approach include:

• Generally ‘fit and forget’ measures, that permanently reduce heat demand and peak heating loads.
• Can reduce running costs and fuel poverty risk regardless of heating system type.
• May improve comfort even in under-heated homes by enabling warmer conditions at similar running costs.
• Improved insulation and ventilation can reduce risks associated with damp, condensation and mould.

Main issues/challenges of this approach:

• Fabric measures do not address the carbon intensity of heating energy use. The amount of greenhouse gas emissions (measured in carbon dioxide equivalent, CO2e) associated with heating energy depends on the heating system, heating demand and fuel source used in a home. While fabric measures can reduce demand, it will be necessary to move away from heating with fossil fuels to ultimately decarbonise heat. The UK and Scotland carbon budgets, discussed in Section 8.2, both assume a far lower contribution to overall emissions reductions from homes from energy efficiency measures than from low-carbon heat.
• With many homes having adopted basic fabric measures (loft insulation, cavity wall insulation), further improvements, as required in a deep retrofit, tend to be more costly and disruptive (e.g. other wall insulation approaches, floor insulation). Deeper fabric measures are therefore currently occurring at a relatively slow rate.
• Inappropriate or poor-quality fabric installations can lead to undesirable unintended consequences. Costs may be expected to increase for some fabric measures where additional quality control and assurances are needed to ensure appropriate installation quality to help avoid mistakes experienced in some previous schemes (discussed further in section 7.4.2). Perception of elevated risk may make consumers resistant to deeper retrofit measures.
• Practical, technical and/or heritage constraints mean that not all homes are equally suited to a fabric first strategy. Real-world situations and opportunities can influence the sequence that retrofit measures are carried out, which may move away from a fabric first ideology. For example, when other non-energy-related works or upgrades are taking place, new heating or renewable energy upgrades may become more cost-effective. Prioritising decarbonisation of heat

Decarbonisation of heat

Decarbonisation of heat is a transition from fossil fuel-based heating systems to low or zero emission (clean heat) heating systems. Clean heat systems can often be installed without extensive fabric retrofit measures, although this may have implications for efficiency, comfort and running costs. This will directly contribute to decarbonisation, although it will not necessarily reduce the heating energy requirements.

Main benefits/opportunities of prioritising decarbonisation:

• Electrification of heat is expected to make the greatest contribution towards achieving zero emissions targets in homes, as the electricity grid decarbonises further over time.
• Despite electricity prices typically being higher than other fuel sources (particularly mains gas) cost savings can sometimes be achieved by switching from a traditional heating system with no other measures. For example, one study estimates that around a third of households in England would see reduced energy bills if switching from a gas boiler to a heat pump. This generally occurs in homes with the oldest and least efficient gas boilers (e.g. back boilers) (Leather and Marshall, 2025).

Main issue/challenges with decarbonisation:

• The Climate Change Committee (CCC) 2025 progress report (CCC, 2025c) indicated that decarbonisation of heat was happening too slowly. In particular, there were insufficient policy plans in place for 14% of emissions, partly due to a lack of programmes and funding towards heat pumps. There is concern that requirements for implementing fabric measures before installing clean heat systems is hindering progress. There is also evidence that suggests that clean heat systems can operate without deep retrofit in many homes, although additional fabric measures may still be important to improve affordability and comfort. (Eyre, N. et al. 2023).
  
• While clean heat systems may be technically viable in poorly insulated homes, acceptable running costs and comfort levels may still require additional measures. While the Leather and Marshall study noted above (2025) estimated that around a third of households would see bills reduce when switching from a gas boiler to a heat pump, the other two thirds would see bills increase. In many cases, the increase would be modest (around £32 per year). However, 22% of those switching from mains gas would see bills increase by over £100 per year. This could be a particular concern for low-income households or those in, or at risk of, fuel poverty. In such cases, fabric improvements or some other mitigation would be required to prevent bill increases. Other approaches may include capitalising on savings from off-peak tariffs or utilising ‘social tariffs’ for vulnerable households (National Energy Action (NEA), 2023; Leather and Marshall, 2025).
  
• Systems may be oversized if/when building fabric is later upgraded. This may not necessarily be an issue for efficient operation. However, it may mean that a more expensive system cost was incurred compared to if the system were sized after fabric measures (Nesta, n.d.).
  
• The Electrification of Heat demonstration project carried out by Energy Systems Catapult found that heat pumps can be used efficiently in a wide variety of buildings (ESC, 2024). A large number of the test homes in the study were in Scotland. While this is positive, it was found that installation quality can have a notable impact on achieved system efficiency. In most cases, heat pump efficiency was lower in practice than quoted at the design stage. This will have implications on expected running costs. However, impact on running costs was not an apparent focus of the trial.
  
• Unlike the ‘fit and forget’ nature of fabric measures, heating systems have to be maintained and replaced at the end of their lifespans. Hence there will be maintenance costs and replacement costs to consider. This is true of any type of heating (with greater or less frequency). However, capital costs can be higher with systems such as heat pumps than with other traditional heating systems.

Impact of heat decarbonisation on the electricity grid

A transition to increased use of electric heating will increase electricity demand, potentially aligning new peaks with periods of already high demand. This raises concerns for the electricity network. Fabric efficiency measures can help reduce peak electricity demand, though flexible operation of electric heating systems and Time-of-use tariffs could be an alternative strategy to help mitigate impacts on the electricity network. This can also bring savings to consumers, which can be enhanced if PV and battery storage is also employed (Rosenow and Lowes, 2023; Moss et al, 2024; Nesta, 2025a). Rosenow et al (2020) observed that network reinforcement costs could be deferred where technically difficult through short term hybrid approaches and by capitalising on flexibility.

An earlier study for BEIS suggested that 84% of rural homes in England and Wales could be electrified at then-current (2018) levels of insulation. This considered expected loads on the low voltage network relevant to average peak winter day temperatures. This increased to 93% of rural homes if all those suitable had loft and wall insulation installed. However, the proportion of homes the current low voltage network can support dropped considerably when a 1 in 20-year winter peak scenario was considered. Peak demand shifting, as noted above, and/or thermal stores or battery storage are noted as helping to reduce constraints on the low voltage network (Myers et al, 2018).

Forms of clean heat

The clean heat technologies most often discussed for heat decarbonisation in the UK are:

• various types of heat pumps
• other electric heating (electric boilers, panels heaters, storage heaters)
• district heating networks (with low or zero carbon sources) (out of scope for this study)

All systems have their associated risks and typical suitability.

Heat pumps (e.g. air source, ground source, air-to-air, etc): As set out later, these are generally considered to be technically suitable for most buildings (particularly Air Source Heat Pumps (ASHPs), due to their cost and flexibility). They are an existing, known technology, and are therefore the main form of heating assumed in domestic decarbonisation trajectories (CCC, 2025b). Some types can face issues in relation to space and noise constraints that can influence selection. Many may require associated works, such as changes to pipework or emitters.

Hybrid heat pumps: These combine a heat pump with another heat source (such as a gas boiler), and associated controls to optimise efficiency and running costs. They can offer an interim solution to full decarbonisation in homes where installing just a heat pump would be unfavourable. This may include older properties with high heat demand where fabric efficiency measures are impractical or excessively costly. (EHAS, 2019). Hybrids could also help reduce the impact on the electrical network of increased peak demands that may be presented by a significant roll out of traditional heat pumps without any integrated flexibility.

Direct electric heaters: This can include wall mounted electric radiators, storage heaters, infra-red heaters, electric boilers and similar. These are generally affordable to buy and relatively easy to install. However, they tend to have higher running costs compared to heat pumps, because the efficiency with which they deliver heat cannot exceed 100%. (Direct electric heaters are 100% efficient at converting electricity into heat. Meanwhile, heat pumps use electricity to upgrade heat from the air or ground via a compressor, meaning they can achieve efficiencies of 250-400%.) Running costs may be acceptable in smaller and/or highly energy efficient homes, or where occupied hours are low or highly intermittent.

Solar thermal systems: Solar thermal systems capture sunlight to produce heat. These were not a significant focus of this study, largely because hot water provision was not central to balancing fabric efficiency and clean heat measures. PV systems, which instead convert sunlight into electricity, were more commonly discussed in the literature in relation to reducing the running costs of electrified heating.

Biomass/bioenergy heating: Biomass heating systems are not generally considered a mainstream solution due to constraints on sustainable fuel supply and competing demand from other sectors (Foster et al. 2020). Despite this, they may remain relevant in some properties with limited suitability for electrified heating systems. As with other heating types, fabric improvements can help reduce energy demand and running costs.

Associated health, wellbeing and socio-economic impacts of retrofit

Impact on the National Health Service

Improving poor housing is predicted to have significant benefits on occupant health, comfort and wellbeing. BRE research on the cost of poor housing in England found that mitigating hazards (which include excessive cold and damp as well as other hazards) could save the NHS over £1 billion per year (Garrett, 2023).

A Climate Services for a Net Zero Resilient World (CS-N0W) study simulated health impacts of retrofit measures alongside energy and carbon impacts (Symonds et al. 2025). It found that full fabric retrofit of homes in England could provide NHS cost savings of around

£0.26 billion over 25 years. The addition of a heat pump to that scenario was forecast to potentially save the NHS around £1.3 billion in total over a 25-year modelling period. This is because a 1°C increase in average internal temperature was assumed from continuous, lower temperature operation of the heating. (This phenomenon had been witnessed in studies of ASHP use, though was acknowledged as a ‘behavioural’ factor rather than inherent to the technology.) A further £0.5 billion in NHS savings over 25 years was predicted by also switching to electric cookers. This would reduce indoor air pollution, which would benefit cardiovascular and respiratory conditions.

A cost analysis for Scotland by the University of Glasgow estimated that annual NHS costs associated with poor housing in Scotland was around £530 million (Boyd et al. 2025).

Reported health, wellbeing and socio-economic benefits and risks with fabric measures

Homes that do not have an energy efficient building fabric can experience a poor internal environment, including damp, mould and reduced indoor air quality. Heating costs may not be affordable for households if energy demand is too high. When fabric energy efficiency measures are implemented in a retrofit, it can improve these HWS aspects by making a home easier/cheaper to heat. Increased temperatures help to combat damp and mould, and better ventilation provision can improve air quality. Improved warmth and physical environment can contribute to improved cardiovascular and respiratory health.

Improvements in all of these factors can reduce stress, leading to improved mental and social outcomes (Public Health Scotland (PHS), 2021; BEIS, 2020).

However, there have been reported failings with fabric retrofit due to poor design and installation quality, and inadequate ventilation provision (National Energy Action, 2025; National Audit Office, 2025). These can undermine the intended HWS and energy benefits, leading to localised increased heat loss, condensation and mould, and in severe cases, physical damage to the building. Overheating can also potentially be a risk in highly insulated homes, which can be exacerbated by a lack of adequate ventilation (PHS, 2021; BEIS, 2020).

The DEEP project (Glew, 2024) specifically assessed overheating risk associated with retrofit interventions. It found that retrofitting can help reduce overheating risk, but it depended on what measures were installed. Improved airtightness, loft and floor insulation typically led to marginally increased risk. This was a result of reduced beneficial summer air changes, and reduced heat exchange with adjacent colder spaces respectively. Room-in-roof and solid wall insulation reduced overheating risk by fundamentally limiting transfer of heat into spaces. However most homes, even those with beneficial retrofits, were found to fail overheating criteria when 2050 weather scenarios were considered.

In some retrofit cases, energy savings may be short-lived or not in line with expectations due to ‘rebound effects’, particularly if homes were previously underheated (Peñasco and Díaz Anadón, 2023). A rebound effect is when expected energy savings are not delivered in practice due to changes in occupant behaviour.

However, rebound effects may still represent positive outcomes in terms of home health and comfort. A retrofit may therefore be considered successful if occupants are able to achieve a warmer and healthier home at a similar running cost (Nesta, n.d.).

Reported health, wellbeing and socio-economic benefits and risks with clean heat measures

Electric-based heating systems are ‘clean’ at the point of use (and are expected to completely decarbonise as the electrical grid does so). It is typically assumed that if homes switch to clean heating, they will most likely also switch to electric cooking. This would allow complete removal of the need for a secondary fuel source, which would save money on separate bill standing charges. This would also further reduce risk of internal air quality detriment from the burning of fossil-fuels indoors.

However, clean heat systems may fail to achieve quoted efficiency or running costs if they are poorly installed and/or commissioned (ESC, 2024). This can lead to higher energy bills than expected, which is particularly detrimental to households with limited budgets and can increase risk of fuel poverty.

Intermittent high temperature heating patterns, typical of traditional heating systems, can lead to suboptimal heat pump operation, resulting in lower system efficiency and reduced thermal comfort. Heat pumps generally operate most efficiently with continuous heating schedules and limited difference between setback temperatures (i.e. backstop temperatures typically set when a home is unoccupied) (Palmer and Terry, 2023).

Studies suggest that maintaining more stable indoor temperatures may also support improved health outcomes. Specifically, raising backstop temperatures from 16°C to 18°C was found to cost only a relatively small amount extra in a typical home (with gas heating). However, the lower temperature can potentially lead to significant negative health impacts (NEA, 2024a). Therefore, where heat pump systems are able to operate affordably at a relatively constant temperature, this could deliver improved comfort, beneficially impacting the health of occupants. The Scottish Fuel Poverty (Targets, Definition and Strategy) (Scotland) Act 2019 and Regulations 2020 recognises extended heating requirements for some households, including older people, young children, and those with health conditions. Such heating regimes may facilitate more efficient heat pump operation. The extent to which the Act’s enhanced temperature regime could be efficiently delivered by clean heat systems does not appear to have been specifically explored in the literature.

While heat pumps typically operate most efficiently at low circulation temperatures, the disruption of replacing emitters/radiators to accommodate this can be off-putting.

However, adopting a high temperature heat pump could avoid the need to replace emitters and allow a heat pump to remain a cost-effective solution (Palmer and Terry, 2021).

Evidence related to the optimal balance of fabric efficiency measures and clean heat in retrofit

Rosenow & Hamels (2023) considered numerous stock and system level modelling studies from across Europe. They summarise that decisions on the optimal balance of fabric measures and clean heat would depend on various perspectives, in particular:

• individual building owner versus stock and energy system level optimisation
• concern for the total cost of measures (capital and operational) versus either capital or operational/running costs separately (e.g. owner occupiers, landlords, rental tenants)
• whether also focussing on addressing wider health, wellbeing and socio-economic outcomes, including fuel poverty risk.
• the timeframe considered for assessment (i.e. short versus long term costs and impacts).

These factors were borne out in the present study. Differing perspectives arise from the literature depending on whether system level (i.e. electricity grid) impacts are considered for example. In addition, determination of an optimal balance between fabric and clean heat measures varies depending on whether the focus is on:

• the technical viability of clean heat operation in isolation of running costs.
• assessment of total cost of ownership, with potential trade-off between up-front costs and ongoing costs.
• avoiding increased running costs (particularly to avoid risk of worsening fuel poverty).

Sensitivity to energy pricing

All studies generally cite the sensitivity of their recommendations to the relative prices of gas and electricity. Electricity is currently more expensive than mains gas, which makes delivering an equivalent amount of heat more costly when electrifying from gas. Some studies quote the electricity to gas ratio recently reducing to approximately 4:1 (e.g. Nesta, n.d). However, the ratio in Scotland in February 2026 was 4.7-4.8:1 (Ofgem, n.d).¹ Minimising the impact of a fuel switch on energy bills relies heavily on enhancing the building fabric and/or deploying clean heating systems with higher efficiencies. As heat pumps can operate at efficiencies around 300% (indicated by their coefficient of performance, i.e. COP = 3), they can help to close the running cost gap in homes where they are suitable. Recent trials of heat pumps found in-use seasonal performance factors to average just below 3 (ESC, 2024).

¹ The January to March 2026 Ofgem price cap rates per kWh for direct debit single rate electricity were 27.83p for southern Scotland and 28.36p for northern Scotland. The direct debit rates for gas were 5.89p per kWh for all of Scotland.

Time of Use (ToU) tariffs and smart controls are examined in some studies. Shifting heating periods to times of low pricing can help to reduce running costs.

Energy pricing is largely outside the Scottish Government’s control (it is a UK Government reserved issue). Some studies have explored the potential influence of changing energy prices. However, policy decisions will likely need to be based on conservative assumptions in line with the status quo.

Assumptions for carbon budgets for the UK and Scotland

The Climate Change Committee (CCC) has developed the seventh carbon budget for the UK (2025a) and a Carbon Budget for Scotland (2025b). Both budgets are based on decarbonisation in homes via electrification of heat, primarily through the adoption of heat pumps. At a UK level, half of homes are expected to run on clean heat by 2040. Scotland’s pathway indicates 40% of homes should have a low-carbon heating system by 2035. The Scottish carbon budget acknowledges that for tenement buildings, heat networks or communal heat pumps (including high temperature systems) are likely to be most suitable.

With many homes still relying on fossil fuels to 2035/2040, improving home efficiency is expected to help reduce emissions in the short term. However, these fabric efficiency improvements will only deliver 14% of the planned emissions reduction from residential buildings in the Scottish carbon budget in 2035. This compares with 54% emissions reductions expected to be achieved through low-carbon heating. Equivalent figures for the UK carbon budget, to 2040, are 10% emissions from energy efficiency and 66% from low-carbon heating. Both carbon budgets assume most homes would install ‘small’ cost effective energy efficiency measures in this time. This includes draught-proofing and hot water cylinder insulation. It is acknowledged that the majority of homes with lofts or cavity walls are already insulated to varying standards. In the UK pathway, it is assumed that further viable cavity walls will be insulated and all remaining potential for top up loft insulation.

Solid wall insulation is stated in the UK budget as generally not being cost effective and is only assumed to be installed in around 15,000 homes. In the Scottish pathway, it is proposed that 9% of households would install ‘large’ energy efficiency measures, such as cavity wall, loft and floor insulation. No specific targets are proposed for solid wall insulation.

The Scottish carbon budget acknowledges the importance of addressing fuel poverty and cites the need for electricity prices to be addressed by UK Government. The focus is however on achievement of net zero by 2045. No specific measures or considerations are cited in relation to reducing fuel poverty, other than setting minimum energy efficiency standards for privately owned homes. Fuel poverty rates are expected to reduce through insulating homes, and where clean heating will substitute for expensive fuels such as oil.

These pathways set the overall targets related to decarbonisation. But national policy will need to create the structure through which this will be delivered, while also protecting health and mitigating fuel poverty risk.

Comparing equivalent studies of optimisation scenarios for the UK and Scotland

A study was carried out for the Department for Business, Energy and Industrial Strategy (BEIS) on Cost-Optimal Domestic Electrification (CODE) (Palmer and Terry, 2021). This specifically sought to identify a cost-optimal balance of fabric measures alongside clean heat options for typical UK housing archetypes. The study primarily considered the total cost of ownership of selected measures (i.e. up-front capital costs, running costs, and maintenance requirements). It therefore best represents the position of households responsible for both the cost of retrofitting and the ongoing energy bills, i.e. ‘able to pay’ owner occupiers.

It found that electric heating can be cost effective in UK homes without extensive insulation upgrades. Data from this study underpins England’s Warm Homes Plan, discussed earlier (DESNZ, 2026).

The CODE study was sensitive to the timeframe over which measures were assessed and quoted results over a 15-year period. Short timeframes (e.g. 5 years) favoured heating systems with low up-front costs, but tended to result in higher running costs. Meanwhile, longer timeframes (e.g. over 20 years) favoured storage heaters, despite higher ongoing running costs. This is because heat pumps incurred further maintenance and/or replacement cycles over that period while storage heaters did not. Solid wall or floor insulation were still not deemed cost-optimal over longer timeframes.

These trade-offs could manifest themselves in practice in some property tenures unless backstops were imposed around approaches to deploying clean heat. For example, landlords of rental properties may wish to focus on minimising capital expenditure to meet any imposed decarbonisation requirements. However, this could drive up energy bills for tenants, which could increase risk of fuel poverty.

WWF Scotland commissioned a similar study (ScotCODE) by the same research team for Scottish housing (Palmer and Terry, 2023). The ScotCODE analysis demonstrated that optimisation outcomes for Scottish homes differ materially from wider UK findings. Unlike the UK-wide CODE study, ScotCODE found additional fabric measures to be cost effective in many Scottish archetypes. This reflects the influence of Scotland’s colder climate and housing stock characteristics on heat pump performance and running costs. In particular, the Seasonal Coefficient of Performance (SCOP) of heat pumps was noted to be lower in Scotland than England due to the climate. This should be borne in mind when considering findings from other UK-wide studies that do not explicitly consider Scottish circumstances. It suggests that findings from such studies could be overly optimistic and therefore recommendations may be less suited to deployment in Scotland. The ScotCODE study found that:

• fabric improvement measures (loft, cavity insulation, draught proofing and double glazing) significantly improved heat pump performance and reduced running cost. Solid wall insulation was more cost effective than using heat pumps with larger radiators for older stone homes (over a 15-year assessment timeframe). However, it was noted that such measures were expensive, and suggested they could be recommended as ‘optional’ where affordable.
• ASHPs were the most cost-effective electric heating solution in almost all types of Scottish homes (alongside the fabric measures noted above). Off-mains gas homes on oil or electric storage heaters saw the largest bill reductions. Air-to-air heat pumps were the most cost-optimal solution in pre-1919 tenements, though were only marginally more cost-effective than an ASHP. Air-to-air heat pumps were also suggested as a solution in ‘challenging homes’, (i.e. space constrained, or heritage properties).
• running costs were lower with a heat pump in many homes. However, some homes switching from gas boilers, particularly flats, would see increases in energy bills. Extra measures were modelled and recommended that would also result in reduced bills for these scenarios. These extra measures would result in a higher whole life cost than the ‘optimised’ scenario that gave higher bills. This may be preferable in scenarios where running costs and fuel poverty risk are a concern.
• it was suggested that communal systems or heat networks may be more cost-effective for flats and tenements over individual heat pumps due to characteristics such as space, size and energy demand. However, this was not specifically investigated in the study.

Subsequent investigations carried out on the Scotland data (Palmer and Terry, 2024) highlight that bill savings were highly sensitive to assumptions on gas versus electricity pricing. The ‘medium’ predicted pricing scenario modelled would reduce electricity pricing to 2.57 times that of gas. This was based on a projected drop in wholesale electricity costs and removal of policy costs from electricity pricing, with no change to gas pricing. In this scenario, 85% of homes were expected to experience bill savings. However, very few properties (<1%) would recover the up-front cost of the measures.

This may not be a material consideration for a new heating system since replacement is a necessary periodic outlay as systems reach their end of life. The contention when considering a clean heat system is that, currently, systems such as heat pumps are considerably more expensive than systems they will be replacing.

PV and batteries

The BEIS CODE study (Palmer and Terry, 2021) investigated the use of PV and batteries for typical UK archetypes. They did not feature in the ‘optimum’ scenarios that resulted (i.e. they did not form the most cost-optimal solution for the derived archetypes). However, their benefit for offering demand flexibility was noted. They were also recognised for reducing overall electricity use and offering emissions benefits that were not captured in the purely financial optimisation. It follows that there are wider incentives to government for the deployment of PV and batteries. These relate to overall demand on the electricity network, and in support of more rapid decarbonisation compared to relying on clean heat and fabric efficiency measures alone.

The ScotCODE study (Palmer and Terry, 2023) stated that PV panels and batteries were not part of the analysis, since they effect neither heating nor fabric energy efficiency. However, the study refers to ‘early modelling work and optimisation’ with PV and batteries. It is not clear whether this was modelling in the context of the Scottish archetypes, or was in reference to the earlier UK-wide CODE study. However, it reported that solar PV was economically viable for all house types over 15 years. This is because high electricity prices allowed savings to offset capital costs and reduce overall running costs. It was noted that PV could be deployed to offer lower running costs in fuel poor homes if support was provided to meet capital costs. Conversely, it was stated that batteries were never economically viable over 15 years, in part due to a reported 10-year replacement cycle and associated costs.

Neither study quoted an assumed price for PV systems. The CODE study stated that a single 8kWh battery system was modelled across all house types (assumed to have 6kWh useful potential) at a cost of £4,350. Since February 2024, there is a temporary 0% VAT applied to domestic battery storage systems, which will be in place to March 2027 (HMRC, 2024). A recent industry source suggests 8-10 kWh batteries have a battery-only price of £2,800- £4,500, with an installed price of £4,500-£7,000, as at March 2026 (Smith, 2026). Payback periods, when used to optimise self-generation from PV, are quoted between 6-10 years. This suggests that batteries could currently be economical within their expected lifespans. However, it is stated that batteries will not necessarily be economical for all households, particularly those with favourable export tariffs or high self-consumption of PV generation.

Investigations specifically assessing deployment of heat pumps

As noted in the CCC pathways, it is anticipated that heat pumps will play a significant role in achieving decarbonisation. Many studies have therefore focussed on ‘heat pump suitability’ of homes, or the ‘heat pump readiness’ of homes. Suitability considers the fundamental viability of heat pumps for particular types of home. Readiness considers whether other preceding actions are necessary to facilitate the change. This can include fabric performance, but also other factors, like the suitability of the existing pipework/heating distribution system, or availability of space, etc. The need (or not) for a particular level of fabric energy efficiency alongside clean heat is typically discussed in both types of study.

Studies have taken very different and sometimes novel approaches to assessing potential suitability and readiness. These range from assessing historic boiler performance data (Childs et al. 2025), through to modelling of particular example house types.

Studies use a range of different metrics to define ‘heat pump readiness’, making direct comparison difficult. These metrics generally attempt to assess either the technical feasibility of heat pump operation or the likelihood of achieving acceptable running costs and comfort levels.

Several studies determine that some form of fabric improvements to reduce heat loss are often required for efficient heat pump operation. The extent typically depends on the nature of the property.

An assessment of modelling studies from across Europe found optimal demand reduction to complement heat decarbonisation was between approximately 20 to 50%. Lower levels were acceptable in warmer climates, while higher levels would be favourable in colder climates (Rosenow & Hamels, 2023). Other studies suggest that radiator upgrades to facilitate lower flow temperatures would be needed to improve operating efficiency, particularly in solid wall homes. This would typically be in combination with constant running and minimal setback (e.g. to 18°C) to deliver comfortable conditions (Carbon Trust, 2020; Clarke and de Selincourt, 2024).

Various benchmarks are derived across studies to represent proposed fabric efficiency levels. However, they do not always quote the same metrics, which can make simple comparison difficult. For example, the following studies quote ‘space heating demand’ and ‘fabric heat loss parameter’ respectively.

One study suggested a space heating demand target of 45 kWh/m²/yr. This was quoted to reduce heat pump energy consumption to 1kW, stated as being an acceptable maximum threshold for a heat pump (Lingard, 2020). The ScotCODE study recommends a space heating demand of 65-85 kWh/m²/y for homes to be heated effectively using low flow temperatures. However, it was noted that some homes had a higher residual heat demand with limited scope for further improvement (Palmer and Terry, 2023). Where such targets cannot be achieved, alternative options (e.g. high temperature heat pumps) may be needed.

Meanwhile a study by the Passivhaus Trust estimated that a fabric heat loss parameter of 2.5 W/m²K would offer a break-even point between the cost of gas and ASHP heating. This is lower than the target of 4 W/m²K proposed as representing a heat pump ready standard in the DESNZ MEES consultation (DESNZ, 2025). The latter is intended to represent a peak heat loss threshold for which a low temperature ASHP would technically be suitable. However, it does not explicitly consider running cost implications, as the lower Passivhaus Trust derived target does. Where thresholds only consider the technical viability of heat pump operation, there could be risks that energy bills would rise.

The National Retrofit Hub (NRH, 2025b) have raised concerns about existing studies and of heat pump readiness. It notes that studies do not consider occupant heating patterns, real-world heat pump efficiency and commissioning standards. These omissions could leave residents with higher bills than anticipated. Stakeholders consulted suggested that a range of potential actions are required to ensure heat pump readiness for all. This could include:

• physical measurement to more accurately understand property efficiency, with fabric measures proposed as necessary.
• installation of PV and batteries to help reduce costs where systems would otherwise be more expensive to run.
• post-installation monitoring to optimise system efficiency and comfort.

The potential role of hybrid heat pumps

One study compared hybrid heat pumps with air source heat pumps in properties across all EPC bands. Hybrid heating systems were found to be more cost effective in houses with EPC ratings of D to F, typical of older, poorly insulated houses. The study acknowledged that insulation upgrades have a useful role to play in allowing heat pumps to operate at higher efficiencies. However, high costs of some upgrades to facilitate heat pump usage were seen as a barrier. The study highlighted the potential value of hybrid heat pumps to support short-term heat decarbonisation in poorly insulated mains-gas properties. In particular, it noted that hybrids were the most favourable technology for over 40% of homes in 80% of Local Authorities in Scotland (Hybrid Heating Great Britain consortium, 2025).

Palmer and Terry (2021) also found hybrid systems to be cost effective in their CODE analysis. However, it was noted that these did not deliver complete decarbonisation. Rosenow et al. (2020) concluded that hybrid approaches may help to defer immediate network reinforcement costs.

Hybrid systems may therefore support partial decarbonisation in fossil fuel heated properties in the short term. These homes could be a later focus for decarbonisation pathways, when capital costs and electricity prices are expected to reduce. Such market changes could help make heat pumps more favourable compared to mains gas heating.

Consideration of fuel poverty risks

Fuel poverty emerges across the literature as one of the key constraints on heat decarbonisation pathways. In many cases, the extent of fabric improvement required alongside clean heat is driven less by technical feasibility than by the need to avoid worsening household energy affordability. Many studies therefore note risks related to fuel poverty when discussing the implications of heat decarbonisation. However, assessments rarely go beyond offering scenarios that do not increase running costs compared to existing heating.

A study by Rossi et al. (2026) focussed on retrofit optimisation modelling that mitigates fuel poverty. The scenario assessment included the annualised cost of retrofit measures. In many cases, the high cost of some measures was found to never pay for themselves via reduced operational costs. This was generally the case for solid wall insulation, triple glazing and heat pumps (which aligns with the findings of Palmer and Terry (2024). However, it may be unrealistic to assume that a new heating system would pay for itself through savings.

Many in, or at risk of fuel poverty would be eligible for the cost of measures to be paid for through government grants. Ongoing running costs then become the concern of the occupants. During the scaling exercise to assess stock-level carbon savings, retrofit scenarios that would result in fuel poverty were rejected. The overall potential for national decarbonisation was therefore reduced by a varying extent depending on the method considered for assessing fuel poverty. An indicator linked to households spending more than 10% of their income on energy (as used in Scotland) was found to be most restricting. The findings suggest that targeted financial support and electricity price reform may be necessary to avoid decarbonisation pathways increasing fuel poverty risk. It was noted that solid wall insulation reduces heating demand without increasing risk of fuel poverty.

However, heat pumps would need to be accompanied with policies to reduce electricity costs to prevent fuel poverty.

Recommendations within the literature

Rebalancing gas and electricity pricing: Historically, the UK government has opted to finance policy costs of a range of environmental and social schemes through energy bills rather than general taxation. Most of these costs are applied to electricity bills rather than gas bills, making electricity disproportionately more expensive than gas (Energy UK, 2025). Many sources note that it would be beneficial to the deployment of electrified clean heat to re-balance gas and electricity pricing. This would require moving policy costs either onto gas bills or to general taxation (or some balance between both). Closing the cost ratio between fuel sources would make electrified heat more financially viable. It is however noted that this is an area beyond the Scottish Government’s direct control. A few example references include Eyre, N. et al. (2023) and Nesta (n.d), although there are many more.

Recognise that flexibility is required to meet differing needs: Many advocate that retrofit decisions on fabric and clean heat measures for individual buildings should be considered on a case-by-case basis. Cost effectiveness of measures can vary according to context, e.g. some upgrade costs may be lower if related building works are already planned. Policies and programmes will need to be sufficiently flexible to meet the needs of different buildings and their occupants. Well-qualified advisors will be needed to support households with decision making (Eyre, N. et al. 2023; Retrofit Roundtable, 2024; Rosenow and Hamels, 2023). Nesta cite that, for many homes, relatively modest fabric upgrades could make clean heat (heat pumps) affordable to run. Homes that require more extensive measures should have more complex packages made available to them. However, they warn against treating all homes like the most challenging ones, as this would unnecessarily delay the pace of decarbonisation (Nesta, 2025b). Others note that, due to the expected replacement of heating systems over time, high temperature heat pumps could be used in the short term for immediate carbon reduction. This could buy more time for insulation measures to be deployed, facilitating a more efficient heat pump in the future (Bell, A, n.d).

Prioritise off-gas properties: The ScotCODE study recommends prioritising properties currently on oil over those on mains gas. The study also suggests prioritising houses rather than apartments and flats. These would deliver the greatest carbon savings short term. Reduced system costs over time and rebalancing of gas and electricity prices may help to make gas conversions more cost-effective in due course. The study also recommends homes with existing direct electric or storge heaters be switched to an alternative heating system. This would help address fuel poverty risks, since these systems have high running costs.

Promote opportunities arising from trigger points: Trigger points could be used to drive clean heat or fabric performance, e.g. change of ownership, replacement of a heating system. In such cases, the cost and disruption of retrofit measures can be reduced when combined with other activities (Eyre et al. 2023; Killip et al. 2024). Minimum standards could be imposed at key trigger points. However, Killip et al. note that such standards would inevitably need to be less ambitious than the market’s technical potential. This would be required to allow flexibility to address the many potential varied properties and scenarios.

Greater support for those in most need: Homes need to be comfortable and affordable to heat. This can support a greater focus on fabric improvements, particularly for households at risk of fuel poverty (Eyre, N. et al. 2023). The Green Alliance issued a position paper on decarbonising heat while addressing fuel poverty. They suggest that deep retrofit should only be pursued for fuel poor households and where it will address health and comfort needs, e.g. in social housing. Cheaper measures, such as loft and cavity wall insulation, should be widely promoted alongside heat pumps, as well as utilising ToU tariffs to help reduce running costs (Carr & Bennett, 2024). An economic analysis of housing and health also recommended that policy efforts should focus on retrofit programmes for low income and medically vulnerable populations (Boyd et al. 2025).

Interview insights on health, wellbeing and socio-economic impacts

A series of interviews were caried out with key industry stakeholders to gain views on how HWS aspects may influence the balance of fabric measures alongside clean heat.

Impacts that should be considered when retrofitting

All interviewees generally agreed on the importance of considering the potential to positively influence the following factors when retrofitting:

• cold homes (underheating) as a detriment to health
• risks from overheating
• health impacts from damp and/or mould
• internal air quality
• household bills and risk of experiencing fuel poverty
• mental health (e.g. from concerns about energy bills or unhealthy conditions).
• knock-on impacts on public health services.

Some interviewees also additionally noted:

• the link between a healthier home and better job and education prospects, i.e. less work/school days lost due to ill health.
• wider consideration of indoor environmental quality beyond damp and ventilation, to include impact from chemicals or products used in retrofit.
• noise considerations in retrofit approaches (e.g. better sound insulation) since noise nuisance can impact on mental health.
• lighting and glare (i.e. consideration of shading and passive measures, improvements to internal daylight).
• resilience with respect to energy bills, i.e. protecting from externally influenced price-rise shocks through self-generated energy.
• the impact disruption from retrofit can have on wellbeing and mental health (even if only relatively short term).

Some of these issues can potentially be worsened by retrofit (e.g. if measures compromise ventilation and indoor air quality). However, there is recognition that there are a significant number of wider ‘added value’ benefits of retrofit. Many believed these should be framed as the primary, outcome-based drivers of retrofit policy rather than only an associated benefit of the decarbonisation agenda.

It was also believed that it is not enough to just keep energy bills as they are with a new clean heating system. Due to high energy prices, household fuel bills are currently too high. Retrofit therefore needs to seek to reduce energy bills in all cases, but particularly to reduce risk of fuel poverty.

Positions on fabric energy efficiency measures and clean heat

Respondents had different positions on where they believed the balance should lie between fabric measures and clean heat technologies to ensure positive outcomes beyond decarbonisation. Some felt that fabric measures were fundamental for improved comfort and health outcomes, while also reducing energy demand (to reduce bills); clean heat alone would not improve health in a like-for-like home with existing issues. One interviewee believed there was a more immediate recognition amongst consumers of how fabric measures could help to improve comfort and reduce running costs, compared to heat measures. But it was recognised that measures need to be delivered to a high standard with appropriate consideration of ventilation and thermal bridging to avoid the adverse impacts of some past retrofits.

Some cited that relatively basic, low-cost fabric measures could be sufficient to bring many homes to a ‘good’ standard. This would help to improve comfort, improve efficiency of heating systems, and reduce running costs of clean heat. This included top-up insulation in lofts, and cavity wall insulation where feasible. It was however also recognised that there is limited remaining capacity for such improvements in the existing stock. Draught proofing was believed by some to be particularly important, since reducing air permeability (while ensuring adequate ventilation is maintained) can be beneficial to heating efficiency.

Consistent with the literature review, interviewees highlighted affordability as a key constraint on clean heat deployment. In some cases, fabric improvements will not be feasible or cost effective, and alternative mechanisms would be needed to deliver comfort and clean heat at acceptable running costs. Suggestions included:

• deploying renewable energy (typically discussed in the form of PV, often alongside batteries) to reduce bills and improve energy independence in households with high cost/demand
• instigating ‘social fuel tariffs’ (i.e. subsidised electricity tariffs) for those with justifiable and unavoidable high demand (though it was also recognised that dependence on tariffs is unreliable in case they are withdrawn in future)

Many called for an ‘outcomes based’ approach (i.e. to deliver healthy homes and reduce fuel poverty), rather than focussing on specific measures. This is in recognition that all homes are different and occupants have different needs and priorities. Measured rather than theoretically assumed (modelled) outcomes were also advocated. However, it was acknowledged that there are not robust and universally measured metrics relating to health as there are for carbon emissions and running costs. A study by the National Retrofit Hub (2025) explored potential indicators related to the co-benefits of retrofit, identifying around 40. Yet there was still a disconnect between many indicators and the availability of metrics against which to measure them. Some metrics are used as a proxy for wider outcomes, such as indoor air quality or thermal comfort. But the overall outcome is not guaranteed and will be subjective depending on the preferences of the occupants.

One interviewee noted that while defined performance metrics for health impacts would obviously be ideal, positive change could still be driven by high-level policies. They cited the Well-being of Future Generations Act implemented in Wales (National Assembly for Wales, 2015). Under the Act, public bodies need to consider the impact their decisions may have on people living in Wales under seven headline goals. One of these goals is for ‘a healthier Wales’, another is for ‘a more equal Wales’. Public bodies need to set objectives designed to maximise their contribution to achieving each goal and take steps to meet those objectives. This is cascaded through to grant and procurement conditions, which typically require alignment with the Act’s principles. The interviewee felt that this approach promotes the need for health to be considered, while not being prescriptive as to how; simply setting the ambition makes people think creatively about how things can be improved. To assess whether the Act is having the intended impact, a number of indicators are measured at a national level. In 2025, Welsh Government reported that progress against the milestones was mixed, with around half improved, around a quarter deteriorating, and a further quarter showing little or no change (Welsh Government, 2025).

‘Heat as a service’ solutions were also noted by some interviewees for their change in emphasis on delivering comfort needs rather than meeting energy demand. They went on to stress that having choices and options (rather than a prescriptive approach) was most helpful to adapt to different circumstances. A concept of ‘the right measures for the right properties’ occurred across interviews.

Some emphasised that there should be different approaches for different sectors of society i.e. potentially investing more and pursuing deeper fabric retrofit for households with enhanced needs and most at risk of fuel poverty. It was also acknowledged that cost effectiveness of measures will be different depending on property tenure; economies of scale may influence the viability of measures on area-based retrofit schemes, but equivalent measures may not be so viable for individual property owners.

One interviewee indicated that capitalising on automated demand flexibility with clean heat systems alongside ToU energy tariffs could present an alternative to more extensive fabric measures to reduce running costs. This could also present a wider ‘macro’ benefit of reducing localised energy grid burden at peak times.

Overall, interviewees broadly supported the literature findings that flexibility and affordability are central to successful retrofit policy.

Recommendations for retrofit policy and decision making to better support outcomes

Most interviewees cited the need to address the fuel cost balance between gas and electricity to facilitate decarbonisation while not increasing fuel poverty (noted earlier). Though it was recognised that this is beyond the Scottish Government’s direct control.

Many also believe that policy needs to specifically recognise and target health and wellbeing outcomes in retrofit. It should not just be assumed they would automatically be delivered as a result of decarbonisation.

Respondents unanimously advocated the idea that support (i.e. government funding) should be targeted where the need is greatest, as a ‘social investment’. This was generally acknowledged to include those in fuel poverty, with health conditions exacerbated by cold, with elevated energy demands on health grounds, the elderly and the very young. One interviewee noted that although an enhanced heating regime was recognised for some households in fuel poverty modelling, in some cases this still did not go far enough. 24/7 heating demands (sometimes along with additional energy-using medical equipment) potentially widens the ‘fuel poverty gap’ in practice in some cases. Many also noted rural homes as requiring focus, as properties are typically older, in a poor state of repair, often underoccupied, have expensive running costs (off-gas) and a higher incidence of fuel poverty. The effectiveness of targeting within government schemes was questioned by some interviewees; there was concern that uptake was low in homes most in need, and that delivery was reactive rather than proactive. Empowering communities (including undertaking Community Health Impact Assessments) and supporting local advisors were noted as potential avenues to help address this, though it was not an area of detailed focus for the interviews.

Capitalising on key intervention points was deemed to be important, e.g. replacing a heating system towards its end of expected life, life events prompting household renovation (e.g. retirement, growing family, moving into a new home, etc). Better public awareness of the associated health and comfort benefits of retrofit, as well as on clean heat in general, is needed. This would help drive positive change, linked to such interventions. However, it was also noted that imposing restrictions linked to interventions can be counterproductive, e.g. a requirement to carry out fabric measures to qualify for a clean heat grant. In some cases, the timing may not be ideal (and self-funding may be insufficient) for such linked measures, deterring households from making otherwise positive changes.

This is aligned with a general call for better advice to improve ‘energy literacy’ amongst households. In particular, it was suggested that this should include support to choose the most appropriate measures (The Scottish Government’s HEETSA proposals were welcomed). However, it was suggested this needs to go further to ensure there is support for optimising measures for most efficient use and delivery of comfort after installation. Advice on when and how best to capitalise on ToU tariffs was also noted. It was also suggested that if EPCs were more dynamic and able to capture specific household circumstances and use patterns, they would be more helpful as a retrofit decision tool for consumers. It is noted that work is ongoing for the Scottish Government exploring the potential for interactivity of EPCs.

Several interviewees noted that aftercare following retrofit, and particularly commissioning of new systems, was very different in private versus area-based social schemes. Commissioning quality can be critical to eventual system performance, and hence delivering comfort and intended running costs (noted in ESC, 2024). A focus on this aspect is therefore likely to be required to deliver expected health and financial benefits of retrofit. Improved system efficiencies ensured through quality installations may also negate the need for more extensive measures to deliver acceptable heating running costs.

It was also believed the retrofit narrative should change focus towards health, wellbeing and comfort, rather than decarbonisation. Cost arguments may also have low impact, since many households are cynical of achieving quoted savings. It was noted that recent bad press in relation to poor quality retrofit, as well as instances of mis-selling, have impacted public trust relating to retrofit. A change of focus and improved post-installation support could help win-back trust and drive uptake of retrofit.

Some risks and concerns were highlighted across the interviews that future policy design may need to consider to ensure beneficial HWS outcomes:

• A recognition that clean heat systems need to be ‘affordably’ efficient (i.e. cost of units to deliver warmth and comfort). There was concern that those already with electrical heating systems other than heat pumps would not be prioritised within decarbonisation agendas. However, such households may currently experience compromised comfort (e.g. under-heating) and have high risk of fuel poverty.
• Concern about ‘green gentrification’ occurring as a result of well-intentioned MEES implementation in the private rented sector. The aim of improving minimum energy standards to ensure comfort and reduced energy bills in this sector was welcomed. However, some noted a risk that costs would in some way be passed on to tenants. This may be through reducing other services to recover landlord costs, or simply through increased rent if properties essentially became more desirable.
• Mechanisms are still lacking to address retrofit-related issues in mixed tenure properties. As noted in Section 6, Scotland has a high percentage of flats and tenements where solutions may be practically limited by difficulties in getting all relevant parties to agree on measures. Heat networks are often cited as a likely solution to decarbonise such properties, though such developments will take time. Meanwhile, many households are unable to take action against compromised comfort and/or high bills.

Reflections across the literature and interviews

The recent literature identified during this study generally does not support the need for extensive fabric measures to facilitate clean heat. The need for fabric measures typically relates to the drive to reduce household heating costs and improve comfort and health. Those that advocate a rapid transition to clean heat invariably acknowledge that low-cost fabric measures are also worthwhile. Such measures help reduce running costs, while also increasing system efficiencies and reducing peak loads on the electricity grid.

Some critics of historic fabric retrofit initiatives have cited the rebound effect of unrealised energy savings in practice as a failing. However, it could be argued that such measures have served a purpose in improving comfort standards for occupants. Such instances cast a light on areas of society where lived experience is not represented by a theoretical energy model. Retrofit also has an important opportunity to improve people’s health and welfare. However, this is typically less tangible to quantify compared to carbon or energy bill savings.

Key areas where feedback from interviews align with the literature include:

• For retrofit approaches to be flexible, and not too prescriptive, so as to respond to particular property and household needs.
• Those in most need should be supported with enhanced measures to reduce running costs and improve comfort. This may mean more extensive fabric efficiency measures for some homes, or the addition of renewable generation to offset bills. It may also extend to the instigation of ‘social tariffs’ for subsidised energy.

Design and scope of a potential future modelling exercise

Part of the research brief for this study was to develop recommendations for the design of a future modelling project. It was envisaged that this would be required to explore the optimal balance of energy efficiency and clean heat for Scottish housing archetypes.

Establishing aims and objectives

A workshop was held with members of relevant teams within the Scottish Government. A headline theme arising was the need to consider fuel poverty and decarbonisation agendas concurrently. Consultation responses on the initial Heat in Buildings Plan for Scotland had raised concerns over impacts on household running costs from electrification. The Scottish Government needed to better understand what options would deliver a suitable balance. Key aims from modelling would therefore be to understand:

• which retrofit measures to prioritise alongside clean heat (PV and batteries were also considered in scope for future modelling)
• where certain measures would be best targeted (house types, household demographics and tenures
• fuel poverty implications across all tenures
• cost implications for government-funded support schemes

Measures targeted at fuel poor households should ensure that energy bills should not increase with clean heat systems. This therefore placed an emphasis on understanding running costs before and after measures rather than potentially setting a benchmark affordability level.

Health and comfort impacts of retrofit options were also deemed important. It was recognised that this aspect of retrofit is often more tangible and compelling for households. Appropriate comfort safeguards would therefore need to be considered in any modelling.

The anticipated scale and granularity of any future modelling was also discussed. It was determined that macro level considerations, such as energy pricing and impact on energy infrastructure, would not be a focus. This is because, while clearly important to the decarbonisation journey, the Scottish Government cannot directly influence these.

Investigating potential data sources to support modelling

During the landscape review, numerous data sources were identified that could be relevant to determining a clean heat versus fabric balance. Studies that discussed approaches to archetyping of the Scottish housing stock were also reviewed. A summary of data sources and archetype studies are presented in Appendix B, in Table 2 and Table 3 respectively.

There is apparent variability in defining archetypes, as may be expected. Some studies consider properties grouped by key construction parameters as core archetypes, with some additional metrics as variables on those archetypes. Others consider such variables to form an entirely distinct archetype. It follows that numbers of archetypes quoted in studies can

vary significantly, from tens, to hundreds, to thousands of cases. Fundamentally, any archetyping approach is dependent on the level of detail the archetypes are being used to assess. In the context of assessing retrofit measures, larger groupings may be acceptable where proposed solutions and outcomes for properties are broadly similar.

Developing recommendations

When considering gaps in the literature and existing studies against the Scottish Government’s aims, fuel poverty impact emerges as an area of focus. In particular, the ScotCODE study highlighted in section 8.3 essentially covered many of the priority areas identified during the workshop with the Scottish Government departments. The study highlighted measures required for typical Scottish housing archetypes to implement clean heat without increasing bills. However, it did not specifically consider the impact of proposed measures on rates of fuel poverty occurrence across Scotland.

Drawing on BRE’s expertise in modelling, it was determined that the aims could be met by conducting a relatively typical options appraisal modelling exercise. The modelling tool(s) used would need to be able to appropriately model various combinations of potential retrofit options. Data sets necessary to support the creation of modelling archetypes and to scale these against the Scottish stock were identified. These included the Scottish House Condition Survey (SHCS) and Scottish Household Survey (SHS). Data from these respective surveys is utilised, alongside separate modelling, to estimate fuel poverty statistics for Scotland. This is carried out in-house by the Scottish Government fuel poverty team, with support from BRE to provide underlying home energy analysis.

Aligning present modelling with fuel poverty statistics modelling

In order to estimate the impact of any proposed retrofit approaches on fuel poverty occurrence, it would be necessary to align any modelling outcomes with fuel poverty statistics. Practicalities of the fuel poverty modelling process were therefore explored in more detail to understand how new modelling could consider fuel poverty.

The energy usage of approximately 3000 homes from the SHCS is modelled (by BRE) using the BRE Domestic Energy Model, Version 12 (BREDEM12). BREDEM12 is similar to RdSAP, which is used to produce EPCs for existing homes. However, BREDEM12 allows for additional variables to be assessed compared with RdSAP, including varying climate, occupancy and heating regime. The Fuel poverty (Enhanced heating) (Scotland) Regulations 2020 sets four enhanced heating regimes that recognise some households will require higher heating temperatures for longer periods. The heating regimes ensure that specific energy needs of vulnerable households are reflected in official fuel poverty calculations. The modelled energy data from these sample homes is then taken forward into fuel poverty modelling, alongside SHS data on household income and estimates for fuel pricing. Weighting factors are used to scale this sample to represent fuel poverty occurrence across all Scottish households.

Archetyping presents a challenge when considering how modelling data may be assessed against fuel poverty statistics. Archetypes will typically need to generalise for many aspects, including occupancy and climate, to allow manageable scenario modelling. Meanwhile, each home in the SHCS sample is fundamentally linked to its location and occupants for fuel poverty modelling, and is therefore essentially unique. The BREDEM12 fuel poverty model does not currently carry out optimisation scenarios for properties. The process does not therefore allow impact of retrofit measures on fuel poverty to be effectively tested ‘from the ground up’ within the existing process.

The key outputs from the extensive BREDEM modelling taken as inputs to the fuel poverty modelling are energy bills for the 3000 sample homes. Theoretically, if bills after retrofit measures could be determined by an alternative means, these could be input directly into the Scottish Government’s fuel poverty model. However, it will not be a small undertaking to replicate 3000 properties and simulate multiple retrofit options in an alternative modelling environment.

Two potential options for estimating the fuel poverty impact of retrofit measures are presented in the modelling scope set out in Appendix C. Any approach would require the adoption of simplifications and assumptions. However, absolute accuracy may not be critical to assess the merits of a future Heat in Buildings policy. It may be sufficient to demonstrate that the logic of the approach would benefit those in fuel poverty, and to approximate the extent.

Recommendations for potential further modelling

Appendix C sets out a high-level scope and approach for a future modelling project to address the Scottish Government’s priorities. It focusses on areas that do not appear to be specifically addressed in the identified research and the learnings from this investigation.

The ScotCODE study has been used as a template. As noted above, that work already addresses a number of the Scottish Government’s aims and provides recommendations relevant to much of the Scottish housing stock. The proposed modelling would extend this to consider whether the optimal mix of measures would change when enhanced heating regimes are considered. It would also estimate the impact on national fuel poverty statistics. Results could be scaled against tenure to understand the levels of support that may be required in different sectors, e.g. owner occupiers, private rented, social rented. The findings may influence targets and spending cap considerations proposed for MEES.

ScotCODE modelling was carried out on archetypes reportedly covering 93% of Scottish houses, and similar archetyping logic could be assumed. Not all archetypes were taken forward into the detailed ScotCODE study. It is suggested that fuel poverty statistics are checked against any proposed archetypes to determine if others should be included when assessing fuel poverty.

Conclusions and recommendations

Decarbonisation of homes will require widespread deployment of clean heat systems. However, the evidence reviewed suggests that affordability, comfort and health outcomes often depend on accompanying fabric efficiency improvements and wider support measures. The optimal balance between fabric retrofit and clean heat therefore varies according to property characteristics, household circumstances and retrofit objectives.

Improved fabric performance reduces a home’s heat loss, lowering overall energy demand and supporting the efficient operation of clean heating systems. Carbon budgets recognise that many homes will still rely on fossil fuels for heating to 2035/2040. Improving fabric efficiency is therefore proposed in carbon budgets to help reduce emissions in the short term. However, fabric measures alone cannot entirely decarbonise the heating of homes.

There is conflicting information on the desirable level of fabric performance for a home to be considered suitable for clean heat. A key factor related to the optimal balance of fabric efficiency and clean heat is the potential impact on running costs. Some level of fabric efficiency improvement alongside clean heat is often cited as being required to prevent energy bill increases. But demand shifting and storage can also reduce bills while helping to address grid constraints linked to electrification. Some propose that deploying hybrid heat pumps in the short term will help to limit running costs in poorly insulated homes while still supporting decarbonisation.

Many homes already have basic fabric efficiency measures in place. This offers scope to install clean heating systems without significant additional retrofit in many circumstances. However, potential solutions and running costs will vary depending on the heating system proposed, house type, fabric efficiency, household characteristics, cost and practical considerations such as level of disruption.

Advancements in heat pumps mean that some form of such system is technically feasible in a very wide range of properties. In some cases, high temperature systems would be required. In others, significant heat emitter upgrades would be needed to facilitate efficient low temperature operation. In those with space constraints, air-to-air systems may be favoured. In an expected minority of homes, other forms of clean heat may be deemed more practical. There is therefore some flexibility to overcome potential constraints at a property level when delivering clean heat.

Retrofit offers opportunities to simultaneously address inadequacies in household health and wellbeing, as well as tackling high energy bills and fuel poverty risk. Sources concerned with these impacts typically advocate a focus on high quality fabric measures. Though there are generally calls for an ‘outcomes based’ approach (i.e. targeting real-world impacts and achievements, favouring actual performance over predictions) rather than explicitly favouring particular measures. In situations where further fabric measures are unfeasible or cost-restrictive, alternative options such as PV or tariff subsidies may offer solutions. Thus, policies and programmes will need to be sufficiently flexible to facilitate this.

Recommendations from the literature

• Government home decarbonisation policies should avoid being overly prescriptive. There should be flexibility for households to find a solution that works for their circumstances. However, in the case of rental properties, some level of safeguarding should be applied (via MEES) to ensure cheaper solutions for landlords do not pose comfort and financial penalties for tenants.
• Households in, or at risk of, fuel poverty are likely to require more extensive retrofit support to deliver affordable clean heat and acceptable comfort outcomes. This may mean e.g. deeper fabric efficiency measures for some homes, or the addition of renewable generation to offset bills for others.

Recommendations for further investigation

• Investigate the extent of measures likely to be required to remove Scottish homes from fuel poverty (or at least close the gap) while decarbonising. Further modelling aligned with Scotland’s fuel poverty assessment methodology would provide important new insight that would assist when considering options for simultaneously tackling decarbonisation and fuel poverty agendas.
  

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Appendices

Appendix A : Methodology

Evidence review

A desk-based evidence review sought information from academic articles and grey literature. A selection of search terms used in a search strategy are given in Table 1. A cascade approach was used to identify further relevant references. Research focus was directed to less well-evidenced aspects or technologies as necessary to provide quality content for a thorough review. Inclusion/exclusion criteria were set, including a focus on domestic properties, material linking both energy efficiency and clean heat, prioritising experience of relevance to the Scotland stock. References to wellbeing and socio-economic co-benefits were identified alongside energy/net zero impacts to provide additional evidence.

Full texts of selected documents were reviewed to analyse key themes. Findings were identified across the literature on the interaction between clean heat technologies and energy efficiency and/or provide added value alongside clean heat solutions. Potential risks/concerns were highlighted. Areas where evidence was lacking or inconclusive were identified to inform future research.

• Fabric improvement measures (applied iteratively by capital cost) to include (as appropriate to properties):
  • Draught-proofing (assumed to achieve a specified air permeability)
  • Top-up loft insulation
  • Solid wall insulation
  • Floor insulation
  • Triple glazing

Stakeholder interviews

The CXC project brief required targeted stakeholder engagement. This was suggested in the form of five-to-seven academic or industry interviews, or a small workshop with experts. We committed to undertaking seven interviews for the research, in line with the requirements of the brief. Relevant stakeholders were identified to gather insights into wider wellbeing and socio-economic impacts of installing fabric and clean heat improvements from the perspective of different groups. Some had a UK-wide view and interests, while most specifically operated in the interests of Scotland and/or represented Scottish arms of national organisations. These included:

• third sector organisations focussed on fuel poverty prevention and/or promoting healthy homes
• representatives of academic departments and independent organisations delivering research associated with achieving net-zero
• public sector health bodies

BRE engaged contacts within relevant organisations and additional stakeholders known to the project steering group were also approached.An interview topic guide was developed to identify relevant wellbeing/socio-economic factors of retrofit, the technologies/measures they link to, determinants of positive or negative outcomes, potentially useful data sources, and recommendations to support positive outcomes. Semi-structured interviews were then conducted with the selected stakeholders, allowing for an in-depth exploration of the areas linked with the topic guide.

Following the interviews, common themes were identified from the responses. The extent to which these corroborated or contradicted the findings of the literature review were assessed.

Developing recommendations for the design and scope of a future modelling project

A list of potentially relevant data sources was collated and reviewed, to support further analysis into the interaction of energy efficiency measures with different clean heat measures, in the Scottish context.

Existing work on derived archetypes in relation to retrofit assessment in Scottish housing were identified using web searches. The various approaches were assessed to determine the most appropriate approach to underpin the proposed modelling exercise. The assessment considered the nature of the questions intended to be addressed through modelling and what granularity was required within archetyping to facilitate this.

Data gaps or recommendations emerging from the evidence review were collated. A workshop was also held with members of relevant teams from the Scottish Government to understand their aims and objectives from a potential future modelling exercise. Based on the gaps, objectives, and identified data sources, the research team proposed modelling approaches to address these. These were reviewed by relevant Scottish Government teams and refined to create an overall scope and brief for future work.

Appendix B : List of data sources and archetype studies

Appendix C : Future modelling project

Background

The ScotCODE study (for WWF Scotland) explored cost optimal scenarios (explained in more detail below) of fabric energy efficiency measures alongside clean heat. It also embedded heating control system backstops (i.e. which required the heating system to maintain homes at certain temperatures, e.g. when unoccupied, or through the night) to ensure the retrofit scenarios could deliver on specific ‘occupied’ heating profiles. The housing archetypes adopted reportedly covered 93% of the Scottish housing stock. Properties were grouped according to certain physical considerations (wall-to-floor ratio and roof-to-floor ratio) and their ability to receive equivalent measures. 12 core house types were dynamically modelled, each with three base heating variants. Numerous combinations of clean heat and fabric efficiency improvement measures were then simulated for each (presenting 7,200 scenarios to support an optioneering assessment).

The study primarily focussed on total cost of ownership, i.e. capital costs, running costs, maintenance and replacement costs, which generally fits with an ‘able to pay’ end user perspective. The study also reported running costs separately for the optimised scenarios. In some cases, the optimal total cost scenario resulted in higher running costs. This balance may be acceptable for some households who are driven by a whole life value perspective (e.g. those that are likely to remain in the same home for the long-term), but it is likely to be a significant barrier to others e.g. those in fuel poverty, or risk thereof, and/or those who may not necessarily apply long-term thinking. The study recommended further measures to reduce running costs in these cases, though these would incur additional capital costs.

Notably, the ScotCODE study did not include any assessment of fuel poverty impacts beyond the assessment of further measures to ensure bills would not increase, where required. Fuel poverty is an important consideration for the Heat in Buildings Strategy alongside decarbonisation.

Key gaps in the ScotCODE study include:

• Some excluded house types. While a low portion of the total stock, the relative occurrence of fuel poverty in those types could be reviewed. They could potentially be re-introduced into fuel poverty-focussed modelling if deemed significant.
• Does not consider the 4 x statutory heating regimes considered within fuel poverty modelling.
• Only considers a single climate scenario, whereas fuel poverty modelling considers more granular climate data.
• Hybrid heat pumps. (UK CODE study found them to often be cost optimal, though they still have significant use of gas. They were not included in the ScotCODE analysis.)
• PV was reportedly cost effective, though not discussed in detail.
• Occupancy varies according to house type in the study but is fixed per archetype. (This may not be significant enough to fundamentally influence recommended measures). Meanwhile, fuel poverty modelling includes occupancy and occupation patterns.

These gaps could be explored in a future modelling exercise to assess if/how they influence the selection of measures. Key objectives of modelling, to support the Scottish

Government’s evolving policy considerations, could include:

Objective 1: To assess measures optimisation aligned with fuel poverty heating regimes

Objective 2: Scale for national fuel poverty impact

Objective 3: Assess measures required to reduce fuel poverty

Note: It is assumed a further study would not repeat variants of listed, space constrained or coastal homes. The alternative approaches for these situations were explored in the ScotCODE study. Implications for the alternative heating regimes could most likely be addressed in a qualitative way with reference to the previous analysis.

Modelling objectives

Objective 1: To assess measures optimisation aligned with fuel poverty heating regimes

Aim: Identify combinations of retrofit measures alongside clean heat technologies that would not increase running costs for the 4 statutory heating regimes recognised in fuel poverty modelling.

Modelling approach:

Options appraisal to identify the lowest overall cost scenarios for clean heat that do not raise running costs for each archetype, base fuel and heating regime. Costs will be considered over a set timeframe, to be agreed (e.g. 15 years, linked to typical anticipated heating system lifespans).

As with the ScotCODE study, it is proposed that the modelling would use a representative set of Scottish housing archetypes as test cases. Review whether archetypes excluded from ScotCODE become material when viewed through a fuel poverty lens (using the Scottish Government fuel poverty data); if so, introduce additional archetypes (e.g. total could rise to around 14-16).

• Each archetype would continue to be assessed against three baseline heating types (mains gas, oil, older style electric storage heaters) at average Scottish climate conditions. It is recognised that Scottish fuel poverty modelling considers more granular climate data. However, it is assumed that optimising for alternative climate conditions would incur a disproportionate amount of effort alongside the core range of options proposed for consideration below. A sensitivity analysis on climate is proposed as an option in the ‘scaling’ exercise in Objective 2, below.
• Clean heat systems to be assessed to include:
  • Low temperature air source heat pump
  • High temperature air source heat pump
  • Air to air heat pump
  • Modern, high heat retention storage heaters
• Fabric improvement measures (applied iteratively by capital cost) to include (as appropriate to properties):
  • Draught-proofing (assumed to achieve a specified air permeability)
  • Top-up loft insulation
  • Solid wall insulation
  • Floor insulation
  • Triple glazing
• (Note that, since the majority of homes with cavity walls are insulated, lofts partially insulated and have double glazing (rather than single), these measures would be considered within the baseline archetypes. It is assumed from previous studies that these measures will always be cost-effective (where feasible). Hence any homes found to be viable to receive these would be recommended to do so. Capital costs for such properties would increase commensurately.)
• Additional renewable generation:
  • PV alone
  • PV + battery
• (Options: These could be considered only in scenarios where measures are technically considered optimal but may be deemed too costly, e.g. solid wall homes and/or where (/if) other measures are insufficient to deliver at least running cost parity with a particular heating regime. Could choose to focus on monthly heating season bill reductions from PV (and batteries), rather than annual net savings, to ensure in-month comparability.)
• Test against 4 statutory heating regimes.
• Run separate optimisation scenarios for standard fuel tariff assumptions and a TOU tariff structure (prices to be agreed in both cases).

Key outputs:

• Modelled annual running costs before and after optimised measures, per archetype (derived using set fuel prices – to be agreed). (Assume 14 types x 3 base fuels x 4 heat regimes= 168 baseline scenarios, each allocated an optimisation for standard and TOU tariff structures, with an associated running cost change.)
• Energy demand (kWh) before and after optimised measures, per archetype.
• CO2 emissions (using set emissions rates – to be agreed) before and after optimised measures, per archetype.
• Overall cost of improvement measures required to achieve savings (noting any closely competing cases where, e.g. PV may be deemed more cost effective).
• Narrative accompanying the analysis to highlight measures that do not feature in optimisation scenarios because they do not meet comfort criteria and/or requirement not to increase bills. This is so the Scottish Government may be clear on measures that should not be recommended for archetypes (or at least not in isolation from additional facilitating measures).

Objective 2: Scale for national fuel poverty impact

Aim: To scale up the findings from Objective 1 (i.e. with no increase in running costs) to assess the likely impact on national fuel poverty statistics.

Approach:
It is assumed that the effort of replicating data for the ~3000 properties used as the basis for fuel poverty modelling in a separate energy modelling tool capable of running a more detailed energy analysis used for the described optioneering would be impractical. Two alternative options are therefore proposed and summarised in Table 4, along with advantages and limitations of each.

Option 1: Adapt existing Scottish Government fuel poverty energy modelling

• The energy usage of approximately 3000 homes from the SHCS are modelled using the BRE Domestic Energy Model (version: BREDEM12). (This is currently carried out by BRE on behalf of the Scottish Government. However, the methodology used in BREDEM12 is publicly available.) BREDEM12 allows for additional variables to be assessed compared with RdSAP, though the fundamental operation of the model is similar to RdSAP. The 4 statutory heating regimes are modelled in BREDEM. Estimated energy bills for each of the 3000 base cases are then taken forward into fuel poverty modelling.
• The BREDEM model would need to be adapted to include a number of the clean heat measures and energy systems expected to be a focus of the future modelling. Many assumptions would need to be made on how these systems should be applied in the BREDEM model. These assumptions would inevitably require simplifications compared to more detailed modelling tools used for the previous optioneering exercise. It is noted that this would introduce errors/uncertainties and there is a risk that the subsequent BREDEM modelling would not replicate the findings of the earlier detailed modelling.
• Having established the expected optimal measures for the various archetypes and each associated heating regime via separate modelling, these measures would need to be allocated to each of the 3000 base homes. To facilitate this, the SHCS base cases would need to be filtered according to their characteristics and allocated to their most closely related archetype and heating regime. Relevant optimised measures for the archetypes would then be applied to these base cases in the adapted BREDEM model.
• An estimate of the impact of the measures on Scotland’s overall fuel poverty statistics could then be run by the Scottish Government according to the usual process (including breakdown by tenure).
• Sensitivity analysis could be carried out on test case properties from BREDEM that are equivalent to those used for the detailed analysis in Objective 1. For these cases, appropriate local climate conditions could also be applied to the earlier archetype models, as per the BREDEM test cases.

Option 2: Fuel poverty gap approach

• From the Scottish Government fuel poverty data, dwellings would need to be filtered according to property and household characteristics and allocated to their most closely related archetype and heating regime. Statistics on the frequency of fuel poor homes aligned to each archetype and heating regime would then need to be extracted.
• Identify how many households from the fuel poverty data have a fuel poverty gap less than the respective estimated bill saving derived for each archetype from Objective 1. This would provide an estimate of the number of households that would be expected to move out of fuel poverty as a result of the Objective 1 optimisation savings.
• Sensitivity analysis could be carried out on a selection of example archetypes to assess climate variables. The proportionate impact of each climate across the archetypes may be expected to be similar, since each climate would effectively become a constant in all archetype simulations using that climate. A sample of the archetypes and their respective optimisation scenarios could therefore be run with climate data from, for example, south, mid and northern Scotland. This would provide an indication of how bill savings may change regionally. If the fuel poverty data could be similarly segregated by the climate regions, the fuel poverty gap could then be assessed and compared against the regional modelled bill savings.

Objective 3: Assess measures required to reduce fuel poverty

Aim: Establish what additional measures would be required to close the fuel poverty gap

If the core aim of Objective 1 is only to ensure modelled energy bills are no worse for each archetype, the proposed measures may have a limited impact on fuel poverty statistics (though they may offer decarbonisation while making fuel poverty no worse). A subsequent useful exercise would therefore be to assess the measures required to provide significant decarbonisation and closure of the ‘fuel poverty gap’ for each archetype. This aspect will address a current gap in knowledge and provide analysis to inform the Scottish Government on potential measures recommendations relevant for fuel-poor households.
In this modelling, the fuel poverty gap would become a new target against which to assess energy bill reduction optimisation scenarios.

Modelling approach:

• Extract data from fuel poverty modelling statistics to provide the average/typical/ maximum fuel poverty gap (per house archetype) and how many properties those averages apply to.
• Options modelling alongside clean heat as per Objective 1 scenario, but with the target to reduce the stated fuel poverty gap (e.g. by a certain amount or percentage reduction, in agreement with the Scottish Government), rather than not making bills higher.
• Could use the previous modelling phase as a starting point, so only adding more costly measures rather than an entirely new optimisation process. Rather than re-modelling against different tariff structures, it is suggested that the most cost optimal fuel tariff structure determined for each archetype from the Objective 1 modelling would be taken forward for each case.
• Findings may be scaled, relatively simply, to national level by re-applying the
• numbers of ‘extra measures’ required, to the stock/archetype frequency from which the fuel poverty gap was derived. Alternatively, they could be scaled according to fuel poverty scaling option noted in Objective 2.

Key outputs:

• Modelled annual running costs before and after measures, per archetype (derived using set fuel prices – to be agreed).
• Energy demand (kWh) before and after measures, per archetype
• CO2 emissions (using set emissions rates – to be agreed) before and after measures, per archetype.
• Overall cost of improvement measures required to close fuel poverty gap (noting any closely competing cases where, e.g. PV may be deemed more cost effective)

Optional further modelling variables could include:

• Scenarios considering hybrid heat pumps (to replace only mains gas) to assess impact on short term decarbonisation. CODE study indicates hybrids to generally be favourable, but recognises not full decarbonisation.
• Bio-energy systems (potential for selected house types – this would need further investigation).

General modelling requirements

To deliver an analysis to address Objectives 1 and 2, the modelling tool (or combination of tools)/approach would need to be capable of:

• Representing detailed dwelling archetypes and retrofit measures, including changes to fabric performance, heating systems, emitters, and on-site technologies (e.g. PV and battery storage).
• Assume at least hourly timestep, to consider:
  • PV and battery charging/discharging
  • Optimisation for TOU tariffs
  • Ability to represent heat emitter size vs flow temperatures to assess benefit/need of increased radiator sizes

How to cite this publication:

Weeks, C; Bruce-Konuah, A and Sinclair, C (2026) ‘Balancing investment in clean heat and energy efficiency in Scottish housing retrofit’, ClimateXChange. https://doi.org/10.7488/era/7249

© The University of Edinburgh, 2026

Prepared by BRE on behalf of ClimateXChange, The University of Edinburgh. All rights reserved.

While every effort is made to ensure the information in this report is accurate as at the date of the report, no legal responsibility is accepted for any errors, omissions or misleading statements. The views expressed represent those of the author(s), and do not necessarily represent those of the host institutions or funders.

This work was supported by the Rural and Environment Science and Analytical Services Division of the Scottish Government (CoE – CXC).

ClimateXChange

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+44 (0) 131 651 4783

info@climatexchange.org.uk www.climatexchange.org.uk

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There is conflicting information about the level of fabric performance needed for a home to be suitable for clean heating. Some studies focus on whether a heating system can maintain a comfortable indoor temperature during the coldest expected weather. Others consider running costs, aiming to avoid higher heating bills than the home’s existing heating system. Scotland’s climate and housing stock must be considered to fully understand efficiency and costs.

Improving a home’s fabric can reduce peak heating demand, helping heating systems operate more efficiently and lowering running costs. The evidence also suggests other ways to support clean heating where fabric improvements may be limited, including:

• radiator upgrades
• high-temperature heat pumps
• shifting energy use through Time-of-Use tariffs
• self-generation of power via solar panels
• alternative heat pump systems, such as hybrid or air-to-air heat pumps

The cost-effectiveness of these measures will vary by tenure, and the suitability of different options will depend on circumstances:

• Owner-occupiers may prefer solutions with lower lifetime costs.
• Renters may favour options that do not increase energy bills.
• Some households may prioritise minimising disruption or loss of space.
• For social landlords, economies of scale may be the most important factor.

There has been limited research on the impact of balancing fabric improvements and clean heating measures on fuel poverty. No studies appear to have assessed these impacts using the Scottish Government’s approach to measuring fuel poverty. However, retrofit can improve health and wellbeing, while helping to reduce energy bills and fuel poverty risk. Many households at risk of fuel poverty, or with particular health needs, may require more extensive retrofit measures.

Stakeholders identified several opportunities to support retrofit delivery:

• Using retrofit ‘trigger points’, such as planned home improvements or renovation work, can make upgrades more practical and cost-effective.
• Raising awareness of the health and comfort benefits of retrofit may be more effective than focusing on carbon emissions or cost savings.
• Greater focus on commissioning and aftercare for new clean heating systems could improve efficiency and customer satisfaction, and may reduce the need for more extensive measures to achieve acceptable heating costs.

Recommendations

• Policies should remain flexible and avoid prescribing a single retrofit pathway for all homes.
• Households experiencing fuel poverty, or at significant risk of it, should be supported with more extensive retrofit measures to reduce running costs and improve comfort.
• A modelling exercise should assess the measures needed to lift Scottish households out of fuel poverty, or significantly reduce the gap, while supporting decarbonisation.

If you require the report in an alternative format, such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

Heat networks are a method of delivering heat to multiple properties via a fluid-filled pipe network from a single source of thermal energy. They are a key strategic technology for meeting Scotland’s greenhouse gas emissions reductions targets and consideration of the potential for heat networks in an area is a core requirement for local authorities’ Local Heat and Energy Efficiency Strategies.

Low-temperature heat networks draw thermal energy directly from the ground, bodies of water or from waste heat generated by, for example, industrial activities. The temperature in the pipes is lower than in a traditional heat network and it is upgraded at each individual property served by the network via a heat pump so it can be used for heating and hot water. Traditional heat networks generate thermal energy at a central energy centre, for example through the simultaneous generation of electricity and heat from a gas-fired power station, and deliver it at a higher temperature to individual properties where the heat doesn’t need to be upgraded.

To date, most local and national energy planning in Scotland has focused on higher temperature heat networks. This research aims to support policies, strategies and delivery plans, locally and nationally, by showing where the opportunities low-temperature heat networks are likely to be strongest across Scotland.

Key findings

• There are low-temperature heat network opportunities in each of Scotland’s 32 local authority areas.
• While opportunities are concentrated in more heavily populated regions, such as the Central Belt and urban areas around Aberdeen and Dundee, opportunities can be found in the majority of Scotland’s towns, as well as in rural and coastal villages.
• About a third of Scotland’s housing stock and a third of non-domestic properties – around 1 million properties – could be served by low-temperature heat networks.
• Opportunities are split by those that could serve multiple buildings (11,000 opportunities) and those that could serve single buildings containing multiple individual properties such as block of flats (17,000).
• The majority of opportunity groupings involve modest numbers of properties (up to 30) and total heat demand (up to 300 megawatt-hours per year). However, some groupings have much larger total heat demands, especially if they include anchor loads like hospitals and higher education buildings.
• The majority of opportunity groupings were matched with one or more nearby green spaces that could potentially host hidden heat-collecting boreholes. A smaller proportion was matched with nearby water bodies.

For further information, please read the report.

If you require the report in an alternative format, such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.