The Government has identified what it calls a serious systemic issue with solid wall insulation installed under the Energy Company Obligation 4 (ECO4) and the Great British Insulation Scheme (GBIS), and has instructed Ofgem to oversee checks on every installation made under the two schemes. The statement was made in the House of Commons on 23 January 2025 and repeated in the House of Lords on 29 January 20251.
Around 65,000 households have had solid wall insulation installed under the schemes, which began in April 2022 and May 2023 respectively1. In October 2024, TrustMark, the independent body that oversees tradespeople working in homes, carried out routine audits and found significant examples of work that did not meet the required standard. TrustMark then began suspending installers, and a fuller audit concluded in mid-December 2024. A total of 39 businesses have been suspended from installing new solid wall insulation in people's homes1.
The problems range from minor issues such as missing or incomplete paperwork to major ones such as exposed insulation or poor ventilation, which the statement says could lead to damp and mould if not fixed. Installers must fund any repair work themselves, and the statement says consumers should not be asked to pay anything towards fixing the problems. In the small number of cases where TrustMark audits found health and safety concerns, including wires not being fitted properly, the statement says problems are being fixed urgently, with an expectation they should be resolved within 24 hours1.
"We have instructed Ofgem, the energy regulator, to oversee that work."
The plan covers the following steps:
| Element | Detail |
|---|---|
| Installations to be checked | All solid wall insulation under ECO4 and GBIS, around 65,000 households |
| Who oversees | Ofgem, working with TrustMark and certification bodies |
| Who pays for repairs | Installers, not households |
| Suspended businesses | 39, barred from new solid wall insulation under any government scheme until obligations are met |
| Household letters | From Ofgem, within three weeks of the statement |
The Government says the issues appear specific to solid wall insulation under ECO4 and GBIS, and that stronger checks exist for schemes involving local authorities and social housing providers. It is reviewing solid wall insulation quality under other schemes and says it will report the results1. In the Lords debate, Baroness Bloomfield asked whether the Government would publish a full list of the 39 suspended companies, how suspended companies would be required to remedy their work, and how households would be properly informed. Lord Foster raised the prospect of installers going into liquidation and asked who would then bear the cost of rectification. Those questions were not answered in the text of the debate1.
Why it matters for households
Solid wall insulation is one of the more expensive and disruptive measures installed under ECO4 and the Great British Insulation Scheme, and it is meant to cut heat loss through walls that cannot be cavity-filled. Where it is fitted badly, the household may see little benefit to bills or warmth, and exposed insulation or poor ventilation can create damp and mould. For a home's energy independence, the practical point is that the measure has to perform as designed: a faulty installation leaves the property no better insulated than before, while the disruption and paperwork have already been incurred. The statement says responsibility for finding and fixing problems lies with those who carried out the work, and that households do not need to take action now1. The wider question of who pays when an installer no longer trades has not been answered in the debate1.
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 or TrustMark will arrange a property inspection and the problem will be fixed as soon as possible, with installers required to provide evidence to TrustMark that issues have been properly fixed. All households with solid wall insulation fitted under the schemes will receive a letter from Ofgem within three weeks of the statement, and a GOV.UK advice page for affected households is being set up1. The Government says it will regularly report back to the House and is reviewing solid wall insulation quality under other schemes1.
Sources1 cited
- ECO4 and Insulation Schemes - Hansard - UK Parliament, hansard.parliament.uk