A much fuller audit requested by departmental officials into solid wall insulation installed under the Energy Company Obligation 4 (ECO4) and the Great British Insulation Scheme (GBIS) concluded in mid-December 2024, the Government has said. The audit followed routine checks by TrustMark, the independent body that oversees tradespeople working in homes, which in October 2024 found significant examples of solid wall insulation under those schemes that did not meet the requisite standard1.
Around 65,000 households have had solid wall insulation installed under the two schemes, ECO4 having begun in April 2022 and GBIS in May 2023. Officials informed ministers at the start of December 2024 that early findings suggested widespread cases of poor-quality installations. A total of 39 businesses have been suspended from installing new solid wall insulation in people's homes, and suspended installers will not be able to deliver new solid wall insulation under any government schemes until they have fulfilled their obligations to put any issues right1.
The Government described the problems as ranging from minor issues, such as missing or incomplete paperwork, to major ones, such as exposed insulation or poor ventilation, which, if not fixed, could lead to damp and mould. It said installers must fund any repair work themselves and that consumers should not be asked to pay towards the cost of fixing problems. Ofgem, the energy regulator, has been instructed to oversee that work1.
"In October 2024, TrustMark, the independent body that oversees tradespeople working in homes, did routine audits and found significant examples of solid wall insulation under those schemes that did not meet the requisite standard."
The Government said it believes the issues found so far are specific to solid wall insulation installed under ECO4 and GBIS, and that stronger checks are in place for other schemes involving local authorities and social housing providers. It added that it is reviewing the quality of solid wall insulation under other schemes, with results to be reported to Parliament. It has not been reported whether the full list of the 39 suspended companies will be published; the question was put in the House of Lords and no answer appears in the debate text1.
Why it matters for households
Solid wall insulation is one of the more consequential measures a home can take on, because it changes how the building handles moisture and ventilation as well as heat. Where it is fitted badly, the consequences described in Parliament include exposed insulation and poor ventilation, which can lead to damp and mould. That affects the fabric of the home, not just its running costs, and it is the kind of problem that can surface well after the installer has left.
For a household, the practical point is that the quality of the installation, not just its presence, determines whether the measure delivers lower bills and a warmer home. A poorly fitted wall can undermine the case for the work and leave an owner dealing with remediation. The Government has said consumers should not pay towards fixing problems and that responsibility lies with those who carried out the work, but it has also acknowledged concern about whether installers will still be trading when repairs are needed1.
The wider question is confidence. The Government has said the system of protections for people insulating their homes is fragmented and in need of reform, and that it will review how installers are certified and monitored. For households weighing up insulation and glazing as a route to greater energy independence, the assurance that work is checked and that problems are put right is part of what makes the measure worth having.
What happens next
Ofgem will oversee quality checks on all solid wall insulation installed under either scheme, beginning with every measure being examined over the coming weeks by qualified professionals, including photographic evidence. Where a check raises issues, the certification body overseeing the installer, or TrustMark, will arrange an inspection and the problem will be fixed as soon as possible, with installers required to provide evidence to TrustMark that issues have been properly fixed1.
All households with solid wall insulation fitted under the schemes will be sent a letter from Ofgem within three weeks of the 23 January 2025 statement, setting out the steps being taken and how households can raise concerns. A GOV.UK advice page for affected households is also being set up. In the small number of cases where TrustMark audits found health and safety concerns, including wires not being fitted properly, the Government said problems are being fixed urgently, with the expectation they should be resolved within 24 hours1.
Sources1 cited
- ECO4 and Insulation Schemes - Hansard - UK Parliament, hansard.parliament.uk