Question to the Department for Energy Security & Net Zero:

To ask the Secretary of State for Energy Security and Net Zero, what estimate his Department has made of the total cost of remediation for homes that received substandard external and internal wall insulation through the Energy Company Obligation and Great British Insulation Scheme.

No household should be asked to pay for remediation work. Where non-compliance is found and remediation is needed, the original installer is responsible for the cost of putting the work right. Should the installer have ceased trading, the protections under the 25-year guarantee can be invoked.

The vast majority of remediation for solid wall insulation installed under ECO4 or GBIS has cost between £250 and £6,000 for internal wall insulation and £5,000 and £18,000 for external wall insulation. This would all be covered by the £20,000 guarantee required by TrustMark, should the installer no longer be trading.