The Scottish Government published a review of retrofit assessment on 6 June 2025, as a Policy Report and a separate Technical Report1. The work was commissioned in November 2024 and carried out by a team led by Glasgow Caledonian University, Robert Gordon University, Carbon Futures, and Bield Housing and Care, to support the design of a Home Energy Efficiency Technical Suitability Assessment (HEETSA)1. The research combined four workshops and a survey, supported by a light-touch literature search, and was peer-reviewed by a panel of three experts2. The report is signed by Keith Baker, Magdalena Blazusiak, Natasha Houchin and Ron Mould, and dated March 20251.
The review was originally intended as a single short report, but the Scottish Government said the publication was expanded because of an unexpectedly high level of engagement with the project1. The Policy Report sets out summary findings under four objectives and answers seventeen research questions set by the Scottish Government; the Technical Report carries the methodology and fuller evidence2.
On existing methods, the review found that assessments too often rely on predicted data, lack context-specific assessment and sufficient site investigation, and produce inconsistent and non-comparable results3. It states that Energy Performance Certificate ratings do not always capture the true efficiency of a retrofit, and that measures such as photovoltaic panels or air-source heat pumps may improve an EPC score without addressing poor insulation or moisture risks3. The Scottish Government accepts that EPCs are limited in how improvement measures are specified, which the report gives as the reason HEETSA is being discussed3. Among existing methodologies, PAS 2035 and PAS 2038 with complementing standards such as BS 40104 were considered most holistic, but the review notes these are voluntary, frequently revised, and that most British Standards require paid access3.
The recommendations include a maintenance-first principle, on-site inspections by accredited professionals including invasive inspections where appropriate, householder interviews as a mandatory element, and independent, regulated Retrofit Assessors4. The review also recommends recognising four roles in retrofit delivery: a Retrofit Project Manager, a Retrofit Advocate, a Retrofit Consultant and a Retrofit Assessor4. On market readiness, the review describes its own findings as painting "a fairly bleak, albeit realistic, assessment of the current state of play", citing the Green Deal and an investigation into TrustMark-certified installers of external wall insulation in England2.
"There is an urgent need to address the lack of trust amongst householders when it comes to retrofit projects, which has resulted from, amongst other issues, poor (sometimes detrimental) advice from advisory services, poor and costly installations of measures, and cowboy operators."
Why it matters for households
The review concerns how a home's upgrade needs are assessed in the first place, which sits upstream of any decision about insulation, glazing or heating. Its central criticism is that current assessments can recommend measures that raise an EPC score without addressing underlying building condition, moisture or ventilation, and that recommendations vary with the methodology and assessor used3. For a householder, that bears on whether money spent on a measure delivers lasting improvement or creates a problem that has to be undone later. The review's proposed "no regrets" test is that recommended measures should cause no detriment to the property, should not need removing during future upgrades, and should not risk worse thermal comfort, health impacts or higher bills4. It also recommends that assessments note the potential for district and communal renewable heating, so that individual heating measures are not recommended where a heat network is planned4. The review states that some solutions sit partly or fully outside devolved powers2. Scotland's devolved settlement and its rented-sector standards are set out in Energy and Buildings Policy in Scotland: Devolved Powers Explained and What are the new energy efficiency standards for privately rented homes in Scotland?; the wider framework is covered in UK Home Energy Regulation and Policy: The Full Guide.
What happens next
The review recommends further stakeholder consultation to clarify the role of assessors in the HEETSA model, and that regulation in the immediate term focus on the Retrofit Assessor and consumer protection, with a longer-term commitment to regulate all elements of the HEETSA process4. It also recommends investment in upskilling programmes for assessors, including knowledge of heat and hot water systems and of communal and district heating4. No timetable for introducing HEETSA, and no date for a government response to the recommendations, has been reported1.
Sources4 cited
- Improving home energy efficiency - retrofit assessment review: policy report - gov.scot, gov.scot
- Executive Summary - Improving home energy efficiency - retrofit assessment review: policy report - gov.scot, gov.scot
- Objective 1: Overview of existing methodologies - Improving home energy efficiency - retrofit assessment review: policy report - gov.scot, gov.scot
- Recommendations - Improving home energy efficiency - retrofit assessment review: policy report - gov.scot, gov.scot