UK Inquiry Tracker

Faulty energy efficiency installations

Public Accounts Committee Open Inquiry

Opened: 10 Jul 2025 Parliament page

The Energy Company Obligation 4 (ECO4) and the Great British Insulation Scheme (GBIS), both funded via energy consumers’ bills, are government schemes for the installation of energy-efficiency improvements in people’s homes, such as insulation. Not-for-profit quality assurance company TrustMark identified issues with both schemes, with government announcing in January 2025 … Read more The Energy Company Obligation 4 (ECO4) and the Great British Insulation Scheme (GBIS), both funded via energy consumers’ bills, are government schemes for the installation of energy-efficiency improvements in people’s homes, such as insulation. Not-for-profit quality assurance company TrustMark identified issues with both schemes, with government announcing in January 2025 issues including insufficient ventilation, missing or exposed insulation leading to damp and mould. The PAC has found issues on a number of occasions with similar retrofit schemes. Its 2018 report on the Renewable Heat Incentive found that it failed to meet its objectives or provide value for money against a £23bn total cost to taxpayers, while its 2021 report on Green Homes Grants found the scheme’s design was overly complex and that government had persistently failed to learn lessons from previous energy efficiency schemes. In 2025, the National Audit Office publishes its investigation into energy efficiency installations. Proceeding from the NAO investigation’s findings, the PAC will hear from senior officials at the Department for Energy Security and Net Zero the regulator Ofgem, and others, on subjects including what efforts government has taken to remediate problems, how much this will cost the public purse, and the impact on achieving carbon net zero by 2050. If you have evidence on these issues, please submit here by 23:59 on Thursday 30 October 2025. Please look at the requirements for written evidence submissions and note that the Committee cannot accept material as evidence that is published elsewhere. You can request anonymity or confidentiality when you send evidence, but it is the Committee which decides what information to publish and how. It may treat submissions confidentially, even where you have not requested this. Please note that the Committee’s inquiry cannot assist with individual cases. If you need help with an individual problem you are having, you may wish to read the information on Parliament’s website about who you can contact with different issues . The Energy Company Obligation 4 (ECO4) and the Great British Insulation Scheme (GBIS), both funded via energy consumers’ bills, are government schemes for the installation of energy-efficiency improvements in people’s homes, such as insulation. Not-for-profit quality assurance company TrustMark identified issues with both schemes, with government announcing in January 2025 issues including insufficient ventilation, missing or exposed insulation leading to damp and mould. The PAC has found issues on a number of occasions with similar retrofit schemes. Its 2018 report on the Renewable Heat Incentive found that it failed to meet its objectives or provide value for money against a £23bn total cost to taxpayers, while its 2021 report on Green Homes Grants found the scheme’s design was overly complex and that government had persistently failed to learn lessons from previous energy efficiency schemes. In 2025, the National Audit Office publishes its investigation into energy efficiency installations. Proceeding from the NAO investigation’s findings, the PAC will hear from senior officials at the Department for Energy Security and Net Zero the regulator Ofgem, and others, on subjects including what efforts government has taken to remediate problems, how much this will cost the public purse, and the impact on achieving carbon net zero by 2050. If you have evidence on these issues, please submit via the Call for Evidence portal. The deadline for written evidence will be announced in due course. Please look at the requirements for written evidence submissions and note that the Committee cannot accept material as evidence that is published elsewhere. You can request anonymity or confidentiality when you send evidence, but it is the Committee which decides what information to publish and how. It may treat submissions confidentially, even where you have not requested this. Please note that the Committee’s inquiry cannot assist with individual cases. If you need help with an individual problem you are having, you may wish to read the information on Parliament’s website about who you can contact with different issues . Show less

19 Recommendations

20 Conclusions

1 Report

1 Oral session

7 Letters

1 Event

Activity timeline 10 events

29 Jun
2026

Correspondence

Letter from the Permanent Secretary at the Department for Energy Security and Net Zero relating to energy efficiency installations: respon…

21 May
2026

Correspondence

Letter to the Permanent Secretary at the Department for Energy Security and Net Zero relating to Faulty energy efficiency installations, 21…

7 Apr
2026

Report published

Treasury minutes: Government response to the Committee of Public Accounts on the Sixty-second report from Session 2024-26

23 Feb
2026

Correspondence

Letter from the Interim Permanent Secretary at the Department for Energy Security and Net Zero relating to Recommendation 3 of the Committe…

23 Jan
2026

Report published

62nd Report - Faulty energy efficiency installations

12 Jan
2026

Correspondence

Letter from the Chief Executive Officer of the Installation Assurance Authority Federation relating to the Committee’s evidence session on …

8 Dec
2025

Correspondence

Letter from the Chief Executive of the UK Accreditation Service relating to the Committee’s evidence session on Faulty energy efficiency in…

8 Dec
2025

Correspondence

Letter from the Interim Permanent Secretary at the Department for Energy Security and Net Zero relating to the Committee’s evidence session…

1 Dec
2025

Correspondence

Letter from the Chief Operating Officer at TrustMark relating to the Committee’s evidence session on Faulty energy efficiency installations…

13 Nov
2025

Oral evidence

Oral evidence session

Oral evidence sessions 1 session

13 Nov 2025

View on parliament.uk

Clive Maxwell CB CBE · Department for Energy Security and Net Zero Deborah Chittenden · Department for Energy Security and Net Zero Jeremy Pocklington CB · Ministry of Defence Jonathan Brearley · Ofgem Jonathan Brearley · Department for Energy Security and Net Zero Kiera Schoenemann · Ofgem Matt Gantley · United Kingdom Accreditation Service (UKAS) Simon Ayers MBE · TrustMark

Reports 1 report · click to expand

Title	HC No.	Published	Items	Response
62nd Report - Faulty energy efficiency installations	HC 1229	23 Jan 2026	39	Response document linked

Recommendations & Conclusions

39 results

2 Recommendation

62nd Report - Faulty energy effici…

Set out plans to scale-up the find-and-fix programme for faulty home insulation.

Nearly one year after the problems emerged, around 3,000 homes with defects had been found and fixed out of the more than 30,000 homes estimate to be affected. TrustMark, the government-endorsed quality scheme, did not notify the Department of high … Read more Nearly one year after the problems emerged, around 3,000 homes with defects had been found and fixed out of the more than 30,000 homes estimate to be affected. TrustMark, the government-endorsed quality scheme, did not notify the Department of high levels of faulty installations of external wall insulation until October 2024, more than two years after the start of ECO4 in April 2022. It highlighted similar concerns with internal wall insulation in November 2024. By mid-September 2025, nearly one year later, less than 10% of the estimated total number of affected homes had been found and fixed.1 TrustMark will oversee the programme to find and fix the remaining homes with faulty external 1 This is based on the midpoint of the estimated range of 32,000 to 35,000. 2,934 remediated homes / 33,500 = 9%. 3 wall insulation, of which it estimates there are around 20,000 as of November 2025. It expects to have audited all relevant homes (providing access is granted) within 15 months of when we took evidence in November 2025. TrustMark and the retrofit sector face a serious challenge in scaling-up audit activities at the pace necessary to meet these timescales. The Department plans to identify faulty internal wall insulation through existing audit processes, but we fear it may be overconfident in expecting this approach to be adequate. It is vital that the remaining homes with defects are found and fixed as soon as possible. As waiting times increase, the likelihood of damage occurring increases, and there are immediate health and safety risks that need urgent attention. recommendation a. In its Treasury Minute response, the Department should set out how it plans to scale-up its find-and-fix programme to meet the 15-month ambition and how it will find all the faulty internal wall insulation. b. Given the severity of the issue for residents of affected homes, the Department should be seeking to deliver the find-and-fix programme within a much shorter timeframe and should updat Show less

HM Treasury

Faulty energy efficiency installations

Activity timeline 10 events

Oral evidence sessions 1 session

Reports 1 report · click to expand

Recommendations & Conclusions

Set out plans to scale-up the find-and-fix programme for faulty home insulation.

Update how to protect households from unaffordable repair bills when guarantees are insufficient.

Review risk management and internal escalation systems to swiftly address scheme issues.

Publish an annual report to Parliament on all retrofit schemes, non-compliance and fraud.

Ensure one body is responsible for fraud prevention and detection in future schemes.

Prioritise robust customer protection and remediation for all government-funded retrofit schemes

Widespread major issues found in ECO4 and GBIS insulation installations

Significant public and industry concerns raised over faulty ECO installations

Over 32,000 homes affected by major ECO4 and GBIS insulation faults

Audits reveal widespread performance and safety defects in wall insulation installations

Department accepts unacceptable spectrum of failures in insulation causing health risks

Faulty installations cause severe physical, emotional, and financial distress for households

Installer suspension and reinstatement process insufficient for widespread insulation failures

Less than 10% of homes with major insulation issues remediated after one year

Delays in fixing faulty installations increase property damage and health risks

Provide regular six-monthly updates to the Committee on external wall insulation remediation progress.

Current plans for identifying faulty internal wall insulation lack proactive detection of hidden defects.

TrustMark's registration process fails to adequately assess installer businesses' financial stability and liquidity.

TrustMark lacks direct collaboration with Companies House to prevent directors avoiding remediation responsibilities.

Households lack trust in original installers for defect repairs, despite Departmental competency assurances.

Guarantees cover remediation costs up to £20,000, excluding compensation for health issues.

The guarantee market for solid wall insulation is notably limited to only three providers.

Guarantee invocation processes are complex and lengthy, delaying resolution of serious defects.

Remediation costs for severe installation defects can significantly exceed the £20,000 guarantee limit.

Ensure Government steps in to remediate defects when other avenues are exhausted.

Future retrofit market size and government's Warm Homes Plan details remain unclear.

Department provided limited oversight and influence over ECO4 and GBIS schemes.

Available intelligence on risks and non-compliance was not escalated or consolidated effectively.

Department failed to act sufficiently on identified quality risks in its programme register.

Consumer protection and quality assurance system for ECO4 and GBIS is overly complex.

Department acknowledges current quality assurance system is too layered and fragmented.

Organisations within the system failed to adequately warn Department about risks and flaws.

Department failed to complete a full fraud risk assessment before ECO4 implementation.

No single organisation holds overall responsibility for preventing fraud in ECO4 and GBIS.

Organisations lack requirement to proactively seek fraud, hindered by poor information sharing.

Fraud likely contributes to high defect levels; Department enhancing fraud detection efforts.

ECO failures undermine public confidence in retrofits, prompting Departmental system tightening.

Lack of independence between retrofit assessors and installers is a key design flaw.

Systemic failings identified across retrofit system, prompting departmental reform based on principles.

Correspondence 7 letters