Recommendations & Conclusions
12 items
13
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
To limit further faulty installations, the Department asked the certification bodies and scheme providers, via TrustMark, to suspend installer businesses based on their failure rate. By the end of January 2025, 38 installers had been suspended, preventing them from carrying out new work of this kind under government schemes.22 The …
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To limit further faulty installations, the Department asked the certification bodies and scheme providers, via TrustMark, to suspend installer businesses based on their failure rate. By the end of January 2025, 38 installers had been suspended, preventing them from carrying out new work of this kind under government schemes.22 The Department told us this represented 81% of the external wall insulation market and that 22 installers had been re-instated by the time we took oral evidence in November 2022, 16 C&AG’s Report, para 2.3 and Figure 10 17 C&AG’s Report, para 2.6 18 Q 75 19 C&AG’s Report, Figure 7 20 FEE0003, FEE0021 21 Energy Security and Net Zero Committee Oral evidence: Retrofitting homes for net zero, HC 453, 12 February 2025 22 C&AG’s Report, para 2.13 12 after having fixed the identified defects for which they were responsible.23 However, this reinstatement process only covers remediation work identified by the audit of 1,109 external wall insulation installations, before it was understood how widespread the major failures against the quality standard were.24
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Government response AI 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 suspension and reinstatement of installers.
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HM Treasury
15
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
Delays in finding and fixing these homes increase the risk of damage to the property, including damp and mould, and leave people in homes with unaddressed health and safety risks.29 We asked the witnesses how they would make sure the remaining faulty installations would be found and fixed in a …
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Delays in finding and fixing these homes increase the risk of damage to the property, including damp and mould, and leave people in homes with unaddressed health and safety risks.29 We asked the witnesses how they would make sure the remaining faulty installations would be found and fixed in a timely way.30
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Government response AI 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 delays in finding and fixing faulty installations.
Read full response →
HM Treasury
16
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
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 …
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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.
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Government response AI 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.
Read full response →
HM Treasury
17
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
The Department told us that it plans to identify faulty internal wall insulation through existing audit processes. First, TrustMark and the certification bodies continue to conduct business-as-usual audits. Second, households with concerns can contact their installer and certification body, or the ECO contact centre run by Ofgem, through which calls …
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The Department told us that it plans to identify faulty internal wall insulation through existing audit processes. First, TrustMark and the certification bodies continue to conduct business-as-usual audits. Second, households with concerns can contact their installer and certification body, or the ECO contact centre run by Ofgem, through which calls are triaged and audits arranged when necessary.35 We pressed the Department and Ofgem on how people will know if they have a problem with their insulation, as in some cases the defects may not yet have presented themselves as problems. Ofgem told us that concerns with internal insulation tend to manifest quickly.36 We also pressed all parties to confirm that they were encouraging people to be vigilant to defects and immediately report them. The Department confirmed that this was the case, and that both it and Ofgem had been working with their respective behavioural insights teams to ensure their communications were effective.37 The Department did not outline what would happen if this approach failed to find all homes with internal wall insulation defects, or how they could persuade more people to request audits. Protecting households from the cost of repairs
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Government response AI 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 identifying faulty internal wall insulation.
Read full response →
HM Treasury
18
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
The original installer is liable for fixing the installation to meet the relevant standards. However, the National Audit Office reported that not all installers are complying with the remediation process.38 We asked TrustMark whether the process for installer businesses to become TrustMark-registered (and therefore be able to do work under …
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The original installer is liable for fixing the installation to meet the relevant standards. However, the National Audit Office reported that not all installers are complying with the remediation process.38 We asked TrustMark whether the process for installer businesses to become TrustMark-registered (and therefore be able to do work under government retrofit schemes) includes an assessment of the liquidity and financial 32 Qq 70, 71, 137 33 Qq 137, 138 34 Letter from TrustMark, dated 25 November 2025 35 Qq 139 - 142; C&AG’s Report, para 2.14 36 Qq 140, 141 37 Qq 141, 142 38 C&AG’s Report, paras 2.19 and 2.25 14 stability of installer businesses. TrustMark told us that it does not do a “full dive” into the liquidity and stability of a business, but that in most cases a business must have been trading for at least six months before it can be registered for a given area of work.39
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Government response AI 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 financial stability of installer businesses.
Read full response →
HM Treasury
20
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
Written evidence submitted to us by the Green Homes Group highlighted how some people are unlikely to trust the original installer to fix the issues they created.42 The Department said it is providing assurance to households by ensuring the installer is appropriately certified as competent to do the work, and …
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Written evidence submitted to us by the Green Homes Group highlighted how some people are unlikely to trust the original installer to fix the issues they created.42 The Department said it is providing assurance to households by ensuring the installer is appropriately certified as competent to do the work, and by checking that the repairs had been done correctly.43
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Government response AI summary
The government states that all EWI and IWI measures installed under ECO4 and GBIS schemes should have a guarantee that lasts for 25 years.
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HM Treasury
21
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
If the installer has ceased to trade or fails to fix the issues, remediation costs up to £20,000 should be covered by a guarantee.44 TrustMark confirmed in follow-up correspondence that these policies do not cover compensation for ill health or loss of earnings that might arise as a consequence of …
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If the installer has ceased to trade or fails to fix the issues, remediation costs up to £20,000 should be covered by a guarantee.44 TrustMark confirmed in follow-up correspondence that these policies do not cover compensation for ill health or loss of earnings that might arise as a consequence of mould.45 The Department told us that households had not yet claimed on the guarantees in large numbers and that the installers were remediating the work.46
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Government response AI summary
The government states that all EWI and IWI measures installed under ECO4 and GBIS schemes should have a guarantee that lasts for 25 years.
Read full response →
HM Treasury
22
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
TrustMark told us that three organisations provided the bulk of the cover.47 In written evidence provided after the oral evidence session, the Department confirmed that the guarantee market for solid wall insulation is limited to three companies: QualityMark Protection, which provides regulated insurance-backed guarantees through SafeWorld; and SWIGA and CIGA/IAA, …
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TrustMark told us that three organisations provided the bulk of the cover.47 In written evidence provided after the oral evidence session, the Department confirmed that the guarantee market for solid wall insulation is limited to three companies: QualityMark Protection, which provides regulated insurance-backed guarantees through SafeWorld; and SWIGA and CIGA/IAA, which are asset-backed guarantees.48
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Government response AI summary
The government states that all EWI and IWI measures installed under ECO4 and GBIS schemes should have a guarantee that lasts for 25 years.
Read full response →
HM Treasury
23
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
We asked the witnesses whether they had analysed the guarantee policy wording to ensure they did not include excesses or complex issues that render them useless in practice, or had reviewed the balance sheets of the 39 Q 64 40 C&AG’s Report, para 16 41 Qq 59, 60 42 FEE023 …
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We asked the witnesses whether they had analysed the guarantee policy wording to ensure they did not include excesses or complex issues that render them useless in practice, or had reviewed the balance sheets of the 39 Q 64 40 C&AG’s Report, para 16 41 Qq 59, 60 42 FEE023 43 Q 151 44 Q 58; C&AG’s Report, para 15 45 Letter from TrustMark, dated 25 November 2025 46 Q 82 47 Q 68 48 Letter from the Department of Energy Security & Net Zero, dated 2 December 2025 15 cover providers. TrustMark and the Department told us that TrustMark’s financial protection panel, which consists of external independent members, had initially reviewed all guarantees to ensure they were fit for purpose, and that TrustMark had also been looking at the policies again over the last 12 months to ensure the affected homes were covered.49 In written evidence provided after the oral evidence session, the Department explained that to invoke a guarantee where the installer is still trading but has failed to rectify the problem, consumers must first work through TrustMark’s dispute resolution process. This includes escalating the dispute to the Dispute Resolution Ombudsman (DRO). If the DRO rules in the consumer’s favour, and the installer still fails to rectify the problem, the guarantee provider will at that point step in to remediate the property, assuming the guarantee in question has a “failure to rectify” clause.50 We are concerned that these processes will take too long especially where there are serious defects causing health issues of the occupants.
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Government response AI summary
The government states that all EWI and IWI measures installed under ECO4 and GBIS schemes should have a guarantee that lasts for 25 years.
Read full response →
HM Treasury
24
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
Where guarantees are invoked, the repairs will likely in some cases cost more than the £20,000 covered by guarantee. TrustMark advises it should normally cost between £250 and £18,000 per home to correct the faulty installations, if it can be done before major damage occurs. However, in the worst case …
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Where guarantees are invoked, the repairs will likely in some cases cost more than the £20,000 covered by guarantee. TrustMark advises it should normally cost between £250 and £18,000 per home to correct the faulty installations, if it can be done before major damage occurs. However, in the worst case we are aware of it cost over £250,000 to fix the defects and resultant damage.51
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Government response AI summary
The government states that all EWI and IWI measures installed under ECO4 and GBIS schemes should have a guarantee that lasts for 25 years.
Read full response →
HM Treasury
31
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
The Department told us it designed the consumer protection and quality assurance system in response to the 2016 Each Home Counts review, introducing a single quality mark (delivered by TrustMark) and higher standards that consider multi-measure retrofits in the context of the whole home.69 It told us that the new …
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The Department told us it designed the consumer protection and quality assurance system in response to the 2016 Each Home Counts review, introducing a single quality mark (delivered by TrustMark) and higher standards that consider multi-measure retrofits in the context of the whole home.69 It told us that the new system worked “alongside and with the grain” of the UK’s existing, decentralised model of standards that relied on the private sector.70 However, the Department accepted that the system was “too layered, fragmented and complicated and has not provided the protection that consumers deserve”.71
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Government response AI summary
The response addresses a different recommendation, regarding an annual report on retrofit schemes, and not the conclusion about the complex consumer protection and quality assurance system.
Read full response →
HM Treasury
32
Conclusion
62nd Report - Faulty energy efficiency …
Not Addressed
We asked the witnesses why no-one warned the Department about the risks or flaws with the system it had designed, or considered whether the system as a whole was protecting consumers.72 While TrustMark accepted it should have done much more, Ofgem highlighted their limited role within the flawed system. • …
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We asked the witnesses why no-one warned the Department about the risks or flaws with the system it had designed, or considered whether the system as a whole was protecting consumers.72 While TrustMark accepted it should have done much more, Ofgem highlighted their limited role within the flawed system. • Ofgem accepted that the measures are complex to oversee and deliver, and that the supply chain is very complex, but it told us that the Department was responsible for the design of the scheme, including decisions on how to assess fraud.73 • TrustMark explained to us that, with hindsight, the move from a single-to multi-measure scheme introduced challenges and delivery complications, and therefore risk. It accepted it should have recognised during the design phase that the system under-estimated the level of risk involved,74 and they did not have the resources or digital infrastructure to do it at the time the scheme was launched.75 They and the Department should have recognised this and remediated this short coming much sooner. • UKAS explained to us that the level of audit required of certification bodies for new installers assumed a low level of risk, but that it ought to assume a high level of risk given what we now know. 68 Qq 16, 17 69 Department for Business, Energy & Industrial Strategy and Department for Communities & Local Government, Each Home Counts, December 2016. 70 Q 91 71 Qq 93, 144, 149 72 Qq 3, 18, 29, 56 73 Q 128 74 Qq 2, 14 75 Qq 2, 14; C&AG’s Report, para 21 20 Even though the audit level is set by the Department and not UKAS, we challenged that UKAS should have identified and raised the issue with the Department. UKAS told us it did so but confirmed in follow- up correspondence to us that this was not until February 2025. UKAS apologised for its “role within the system”.76 Insufficient focus on fraud risk
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Government response AI summary
The response addresses a different recommendation, regarding an annual report on retrofit schemes, and not the conclusion about lack of warnings about the risks or flaws of the system.
Read full response →
HM Treasury