Overview

• The National Audit Office reports that roughly 22,000–23,000 homes with external wall insulation under ECO have major defects, with a further 9,000–13,000 internal installations needing corrective work.
• Immediate hazards were identified in 6% of external and 2% of internal installations, including risks linked to poor ventilation and electrical safety.
• The watchdog cites subcontracting to unqualified firms, corner‑cutting and unclear standards, with TrustMark’s limited funding delaying effective monitoring until late 2024 and DESNZ not alerted until October 2024.
• DESNZ and Ofgem have suspended poor‑performing installers, including 38 firms, contacted more than 60,000 households, offered free on‑site audits and set up support to ensure fixes come at no cost to consumers.
• Ofgem estimates 5,600–16,500 falsified installation claims worth £56m–£165m, and the NAO urges deadlines for repairs, annual fraud and compliance reporting, and clearer accountability to be embedded in the Warm Homes Plan.