Improving home energy efficiency - retrofit assessment review: policy report

Executive Summary

In November 2024 the Scottish Government commissioned a team led by Glasgow Caledonian University, Robert Gordon University, Carbon Futures, and Bield Housing and Care to conduct a review to support the design of a Home Energy Efficiency Technical Suitability Assessment (HEETSA).

The research for this project combined a series of four workshops and a survey, supported by a light-touch literature search, and peer-reviewed by a panel of three experts selected for their specialist expertise.

The work was originally intended to be published as a single, short, final report. However, thanks to an unexpectedly high level of engagement with the project, the publication has been expanded in order to more accurately reflect the volume of evidence gathered, and the views of participants. Rather than significantly extend the intended single report, the research team recognised the benefits of producing this accessible summary with clear conclusions and recommendations, alongside a more detailed, technical, and nuanced coverage Technical Report.

For this reason, we are publishing the results of the work as two documents. This Policy Report consists of summary findings under each of four objectives and answers to seventeen research questions set by the Scottish Government. The supplementary Technical Report includes full details of the methodology and a more in-depth coverage of the evidence and the views expressed by our participants.

We encourage readers to use this Policy Report as a jumping off point for reading the sections of the Technical Report that are most relevant and interesting to them.

Our research has highlighted a number of key findings under each objective, as follows.

Objective 1: Overview of existing methodologies

Currently used methodologies often produce generic recommendations, lacking solutions tailored to individual buildings and without sufficiently recognising critical factors like building condition, moisture risks, and long-term effectiveness. Additionally, limited assessor expertise and inconsistencies in assessment outcomes dependant on use of particular methodologies highlight the need for standardized, detailed processes incorporating site visits, consideration of climate and location specific data, and independent assessments. Assessment of clean heating and energy efficiency strategy delivered under HEETSA should thus include:

• Centrally defined operating framework based on real data, recognising building condition and human behaviour.
• Funding aligned to value of quality and long term effectiveness of measures.
• Methods of safeguarding of customer journey supported by competent workforce (designers, assessors and installers).

Clearly defined roles, means of demonstrating competency and compliance supported by stronger collaboration between professionals and clearer funding mechanisms are essential to delivering high-quality retrofits that align with national carbon reduction and energy efficiency goals. Risk management and adequacy of approaches could be supported by development of decision-making matrix/tool to assess suitability of current approaches adequate to the needs of the customer, similar to the Sustainable Traditional Buildings Alliance (STBA) Responsible Retrofit Guidance Wheel^[1].

There are a range of existing methodologies which attempt to go beyond the Energy Performance Certificate (EPC), many of which could be a foundation for a HEETSA, but none of them in isolation could fully support the overarching aim of HEETSA.

Objective 2: Gaps in current methodologies

The current assessment market for retrofit projects has significant gaps in evaluating the technical suitability of clean heating and energy efficiency measures. Individual assessment methodologies lack granularity, ability for comparative evaluation of options, further impaired by knowledge gaps and public scepticism. The focus of HEETSA to address limitations identified in this Objective should therefore be:

• Ability to compare options while considering occupant behaviour, lifecycle impact and mandating Post-Occupancy Evaluation (POE)
• Address current data gaps precluding adequate assessment of communal heating and alignment with Local Development Plans and Local Heat & Energy Efficiency Strategies
• Provide means of independent verification of expertise, training and public awareness addressing knowledge gaps limiting successful customer journey
• Develop a decision-making tool allowing for integration and evaluation of existing methodologies best suited to deliver intended long-term retrofit outcomes.

This approach will require sector-wide framework that enhances training, incorporates lifecycle analyses, relevant data collection and prioritises occupiers ensuring long term benefits through post-occupancy evaluations and adequate customer engagement.

Objective 3: Skills and Qualifications

The impacts of the skills shortage and the measures need to address it cut across many of the themes of this project, and across Scottish policy more widely. However, they are particularly acute for retrofit given the greater attraction of professionals and tradespeople to the new build market. They are also directly impacting on capacity to deliver sufficiently technical standards of independent and impartial advice, leading to projects with sub-standard and negative outcomes, which then impact on public trust in the retrofit and net zero agendas.

Whilst there is no silver bullet solution, there are number of levers that can be employed to start to close this gap:

• Supporting the provision of degrees accredited by the professional associations, and doing more to encourage young people to take them (accepting that the benefits of this will take several years to accrue).
• Enabling adults and professional learners to engage with the growing market for non-traditional learning providers, with their greater focus on andragogy-based learning (adult learning methods, as opposed to pedagogy-based methods designed for children and younger people).
• Understanding the value of enabling professionals to engage with communities of practice, and instilling this in employers.
• Breaking down the emerging role of ‘retrofit coordinators’ into more discrete roles to enable more people from built environment-adjacent fields to transfer into them, to use their expertise to enable more successful retrofit projects, and in turn to empower householders and help rebuild consumer trust and confidence. This differentiation reflects the different, but complementary, skillsets that need to be applied to retrofit projects, and recognises the higher technical knowledge requirements for assessors.

Doing so will require greater engagement with fields such as social care and learning specialists, particularly adult learning specialists, and so we have deliberately attempted to embed these messages throughout both these reports.

Objective 4: Market Readiness

We appreciate that the findings for this objective paint a fairly bleak, albeit realistic, assessment of the current state of play. Unfortunately, we cannot change the past and the impact that a series of mis-firing policies have had on consumer engagement and public trust in the retrofit and net zero agendas (e.g., the Green Deal and the recent investigation into TrustMark-certified installers of external wall insulation in England). We also recognise that far from all of these problems have been caused by the Scottish Government, and some of the solutions are partially or fully outwith the scope of its devolved powers.

However, there are steps that could be taken to build the retrofit market and rebuild confidence and trust among the public and all those involved in delivering retrofit projects:

• Working across policy silos (including within the built environment, energy, and public health) to do more to align retrofit policy and regulation with areas such as the Building Standards, building warrants, and communal and district heating.
• Tackling the skills shortage (see Objective 3).
• Tackling conflicts of interest, and improving consumer protection, complaints handling, and redress.
• Recognising that there is no standard retrofit journey, and designing retrofit policies to capture all possible entry routes and motivations (or lack of them) for undertaking retrofit projects.
• Recognising that enabling successful retrofit projects, and doing so equitably, will be vital to enabling a just transition, and doing more to align the design and delivery of government policy and regulation with this broader goal in mind.

The process we outline, and recommend, is intended to result in occupants being provided with a technically suitable evidence report that will enable them to confidently understand the most appropriate options for pursuing a full retrofit journey. This should include likely costs and energy savings, as well as benefits such as improved thermal comfort, and the options should be tailored to their individual needs.

As such, the proposals for a HEETSA provide a valuable and rare opportunity to stop history repeating itself by addressing and correcting many of the issues that have hampered previous retrofit and energy efficiency policies, and the impacts they have had on public trust and confidence in retrofit programmes, and the wider net zero and just transition agendas. As such, and to better reflect the evidence gathered and the views of our participants, we have not shied away from stepping outside our original remit where we and our peer reviewers felt that this would enable meeting HEETSA’s objectives, and we wish to thank the Scottish Government for agreeing to this flexibility. As a team of multidisciplinary experts, we would have had difficulty doing otherwise.

Finally, we wish to thank all our participants and all those who have supported this work.

Keith Baker, Magdalena Blazusiak, Natasha Houchin, & Ron Mould

March 2025