Routine checks carried out by TrustMark, the independent body which oversees tradespeople working in homes, have uncovered examples of substandard solid wall insulation fitted since 2022 under the Energy Company Obligation 4 and Great British Insulation Scheme – both inherited by the government.

As soon as these issues were identified, the government took immediate action to ensure installers are swiftly suspended, expand checks of solid wall insulation measures installed under both schemes, and implement a comprehensive plan to begin an immediate repair process. The government has instructed the energy regulator, Ofgem, to take oversight of this work to ensure it is swiftly delivered.

The government has demanded that installers fund any repair work themselves, under protections in the schemes. No household should be asked to pay any money by an installer.

Ofgem has now begun writing to all the households affected, explaining that qualified professionals have started a system of checking every installation under these schemes.

In some cases, an on-site visit will then follow to determine whether any insulation work carried out requires a repair. If it does, the certification body that oversees the installer, or TrustMark, will arrange to fix the problem as soon as possible.

Examples of substandard installation range from missing or incomplete paperwork, insufficient ventilation, or missing or exposed insulation, which if left unchecked could lead to damp and mould. While this is a serious issue, this is not considered a widespread threat to safety.

Installers responsible for this substandard work will be forced to fix this at no cost to households and will remain banned from installing new solid wall insulation on any government scheme if they do not fulfil their obligation to put any issues right.

The government is confident that these systemic issues are particular to solid wall insulation installed under the Energy Company Obligation 4 and Great British Insulation Scheme. This is because there is a stronger system of checks and balances in place for other energy efficiency schemes delivered through local authorities and social housing providers.

Minister for Energy Consumers Miatta Fahnbulleh said: “I know this news will be concerning for people who have had external or internal wall insulation fitted through either scheme we have inherited.

“That is why we are taking action to put this right, forcing installers to fix any poor-quality installations as soon as possible and at their own expense.

“Affected households should look out for a letter from Ofgem, which will set out steps to resolve any issues.

“It is clear the existing system of protections for consumers we inherited is in dire need of reform. This will be front and centre of our Warm Homes Plan, as we work to make sure no households are let down in this way again.”