Overview
- The National Audit Office says about 22,000–23,000 homes with external wall insulation require major remediation, with a further 9,000–13,000 internal installations also needing work.
- Roughly 6% of external and 2% of internal installations pose immediate risks such as blocked boiler ventilation and electrical hazards.
- Ofgem estimates 5,600–16,500 falsified installation claims under the schemes, potentially worth £56m–£165m charged to energy suppliers.
- Weak oversight, uncertified subcontracting, unclear standards and installers ‘gaming’ certification processes fueled the failures, with TrustMark not flagging systemic problems until October 2024.
- DESNZ and Ofgem have suspended poor performers, begun contacting tens of thousands of households, offered free on‑site audits with installers liable for fixes, and signalled tighter oversight under a forthcoming Warm Homes Plan.