Source · Select Committees · Public Accounts Committee
Recommendation 16
16
Not Addressed
Provide regular six-monthly updates to the Committee on external wall insulation remediation progress.
Conclusion
The Department and TrustMark told us that TrustMark would oversee a find-and-fix process for homes with external wall insulation. It would offer audits to all homes with external wall insulation installed through ECO4 or GBIS, provide direct oversight to ensure the work is corrected, and work with local communities to build engagement and trust.31 TrustMark and the Department expected, at the time we took evidence in November 2025, all relevant homes to have been audited (providing access is granted) within 23 Q 82 24 C&AG’s Report, para 2.27 25 C&AG’s Report, Figure 10 26 This is based on the midpoint of the estimated range of 32,000 to 35,000. 2,934 / 33,500 = 9%. 27 Letter from the Department of Energy Security & Net Zero, dated 2 December 2025 28 C&AG’s Report, Figures 6 and 10 29 Qq 1, 75, 153; C&AG’s Report, para 2.19 and Figure 6; Energy Security and Net Zero Committee Oral evidence: Retrofitting homes for net zero, HC 453, 12 February 2025 30 Qq 70, 133-137 31 Qq 57, 61 ,76, 139, 151; Letter from TrustMark, dated 25 November 2025; The Department has provided more information on the audit process, including who is eligible and contact information, at: www.gov.uk/insulation-check 13 12 to 15 months.32 The Department told us that any defects identified should be fixed by installers within 12 weeks, although it accepted that this may take longer when the guarantee needs to be invoked. The Department said that “a lot of this” would be resolved within 18 months.33 In written evidence submitted to us after the oral evidence session, TrustMark estimated there were around 20,000 homes with faulty external wall insulation yet to be found and fixed.34 We believe this timescale is very optimistic which is one of the reasons we have recommended that the Department gives the Committee regularly six monthly updates on this matter.
Government Response Summary
The response addresses a different recommendation regarding a blanket ban on external/internal wall insulation installations, not the specific issues raised in this conclusion about the TrustMark find-and-fix process and optimistic timescales.
Government Response
Not Addressed
HM Government
Not Addressed
1. PAC conclusion: A clear and catastrophic failure with external and internal wall insulation installations under ECO4 and GBIS has left more than 30,000 homes with defects. 1. PAC recommendation: The Department should not allow any more external or internal wall insulation to be installed through its retrofit schemes unless it can ensure that every new project will be supervised and checked by someone who is independent, competent and accountable. 1.1 The government disagrees with the Committee’s recommendation. 1.2 The extent and scale of non-compliant external and internal wall insulation under the ECO4 scheme was unacceptable and must never be repeated. The department has greater confidence in the quality of installation and compliance in local authority delivered retrofit programmes and therefore disagree with the recommendation insofar as it relates to schemes other than ECO4 and GBIS. 1.3 Every household with external wall insulation (EWI) installed under ECO4 and GBIS is being and will be offered an on-site audit. Subject to the householder accepting the offer, all EWI installed under ECO4 and GBIS will be checked by an independent, trained and accountable auditor. 1.4 All households that received internal wall insulation (IWI) under ECO4 and GBIS are being written to and can raise concerns and request an audit via the Ofgem contact centre, which will be subject to triage. Where cases meet the threshold of risk factors, households are referred for an on-site audit by an independent, trained and accountable auditor. This includes all ongoing installations. This approach manages priorities and audit capacity in a practical way, taking account of the measured rates of non-compliance. 1.5 All EWI and IWI measures installed under ECO4 and GBIS schemes should have a guarantee that lasts for 25 years, meaning should issues be found in the future, the protections within the guarantee can be invoked within this timeframe. 1.6 The non-compliance rates found under ECO4 and GBIS for EWI and IWI are not replicated in government-funded capital schemes. In October 2025, the department published audit results for the Social Housing Decarbonisation Fund (SHDF) Wave 2 and the Home Upgrade Grant Phase 2 (HUG 2) showing a 0.7% category 1 and 9% major non-compliance rate for all measures and 0% category 1 and 11.7% major non-compliance for solid wall insulation. The system in place for these schemes is much more effective in managing compliance due to the additional controls from Local Authorities and Housing Associations, including mandatory audits from Grant Recipients, as well as separate independent audits by the delivery partner PWC. There is no evidence to require an onsite audit for all solid wall insulation installations under government-funded capital schemes. Where there are non- compliances, the Grant Recipients are responsible for resolving these issues through working with their supply chain as well as supporting residents through the IBG process if necessary. The department is confident that when non-compliance is identified it is swiftly resolved without intervention from the department due to existing checks and the department monitors this process directly when non-compliances are identified through our delivery partners. 1.7 In addition to the ongoing programme of onsite audits, the department continues to implement improvements to the current system of compliance, assurance and wider consumer protections. Improvements include: