Question to the Department for Energy Security & Net Zero:

To ask the Secretary of State for Energy Security and Net Zero, with reference to the National Audit Office Report entitled Energy efficiency installations under the Energy Company Obligation, published on 14 October 2025, how many homes in Wales have had defective retrofit work carried out on them under the Energy Company Obligation scheme.

The Government commissioned an independent statistical audit in April 2025. Two random samples of audits of external (EWI) and internal wall installations (IWI), across the household populations of both schemes were commissioned to understand non‑compliance rates. 98% of EWI audits need to be remediated. For IWI, that number is 29%.

The samples are not large enough to reliably perform any regional analysis. As we continue with further audits, we will seek to begin to collect this data.