Dr Keith Baker, Glasgow Caledonian University, and colleagues explain new Scottish Government proposals for improving the environmental performance of homes. It could be a model for use in other nations. 

Responsible Science blog, 30 July 2025
 

In the UK, Energy Performance Certificates (EPCs) are the primary mechanism for rating the energy efficiency of homes, and making recommendations for improving them. They are a legal requirement for when homes are sold or rented out. Issuing of EPCs is a ‘devolved’ function, which means that the responsibility for managing the system in Scotland, Wales, and Northern Ireland lies with the governments there.

If you’ve ever had an EPC assessment for your home, you’ll probably be aware that the recommendations they make are often not ideal for your property, lifestyle, or budget. Thankfully, the Scottish Government has now recognised this problem and has been developing new legislation to amend EPCs and ensure properties are properly assessed before householders invest in upgrading them.

The EPC reforms will be announced at the end of this summer and, crucially, will include rewording ‘recommendations’ to ‘potential improvement measures’. As members of the ‘short life working group’ established to oversee them, we’re contributing to this process.

However, behind the scenes we’ve also been working on a project intended to ensure that householders in Scotland get the best possible advice and support for retrofitting their homes. The result is the proposed Home Energy Efficiency Technical Suitability Assessment (HEETSA) [1], which is now out for public consultation [2].

HEETSA was one of those projects which substantially outgrew its original scope, thanks to an unexpectedly high level of input from our stakeholders. Using a survey and a series of workshops, we solicited evidence from well over 100 organisations and companies, covering assessment methodologies, skills and qualifications, market readiness, and much more. We began with an aim of producing a 20-page summary report and ended up producing a policy report and a technical report, each running to over 50 pages, and subjected them to several rounds of scrutiny by our peer reviewers. It went well over time and over budget, but we believe what we’ve arrived at is authoritative and definitive.

HEETSA is based on a number of fundamental principles. By adopting a ‘maintenance first’ approach it will ensure we fix buildings first, recognising that as of 2023, a whopping 45% of Scottish properties were still suffering disrepair to one or more critical elements, such as roofs and external walls [3]. Fixing properties first means that householders will be able to reap the full benefits of adding energy efficiency measures and renewable energy technologies. Maintenance has long been a blind spot in policy, and its lack of consideration under the (now withdrawn) Heat in Buildings Bill fundamentally undermined that legislation, so this is a long overdue reset.

Furthermore, the principle of ‘no regrets’ – ensuring that the measures householders are advised to install are appropriate for their properties and lifestyles, and will not need to be removed or replaced as part of future upgrades – is something we have long argued for.

For example, say a property has cavity walls. A basic EPC assessment will usually assume the presence and condition of cavity wall insulation based on the property’s type and age, or rely on a quick visual check. But not all cavities should be filled, and basic assessments often miss cases where filler has settled or been damaged by moisture, meaning adding additional wall insulation can create new, costly, problems. HEETSA is intended to fix this sort of problem.

HEETSA won’t replace EPCs. Householders will still need one as part of selling or renting out a property as energy efficiency ratings are required by law. However, they will now be encouraged to take up a HEETSA assessment, which will include a more detailed assessment of the condition of a property by a suitably trained professional, and an interview to better understand their individual circumstances and needs.

To facilitate this, we have proposed that a HEESTA retrofit process requires a number of roles, including one for more assessors (depending on the measures to be installed), an advocate, and a project manager. Although some householders will need more help than others, and some may be able to manage their own projects. At first, only the role of the assessor will be regulated but, ultimately, we will need to extend that regulation – particularly to energy efficiency advisors.

We won’t get there overnight. We’re up against a skills gap, a lack of trust in experts and advice from years of schemes that have often, at best, failed to deliver, and scandals over things such as spray foam and cladding. But HEESTA has been designed to address the problems of the past, and to help make careers in retrofit attractive both to young people and adults. Our proposals put skills and rebuilding trust at the heart of HEETSA, and set out how community groups and local installers can be part of and benefit from the process without overburdening them.

There’s still some fine-tuning left to be done, and we still have to get the legislation passed at the Scottish Parliament, and we need help with this.
 

Action: If you’re a member of Scientists for Global Responsibility (SGR), please consider responding to the consultation [2], and if you live in Scotland, please ask your MSP to support it. 
 

Dr Keith Baker FRSA is a Research Fellow at Glasgow Caledonian University, a Director of SGR, a Director and Convenor of the Energy Working Group at Common Weal, and a Director of Pattiesmuir Ltd.

Magdalena Blazusiak MCIAT is a Chartered Architectural Technologist, Vice Chair of the Scottish Ecological Design Association, and a lecturer and PhD candidate at Robert Gordon University.

Natasha Houchin FRIAS RIBA is the Lead Building Performance Consultant at Carbon Futures and a Director of the Scottish Ecological Design Association.

Dr Ron Mould FRSA is Net Zero Carbon Manager at Bield Housing and Care and a member of Common Weal’s Energy Working Group.
 

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