Ofgem has written to 65,000 households who could potentially be affected by quality issues with solid wall insulation fitted under two government energy efficiency schemes, the Energy Company Obligation (ECO) and the Great British Insulation Scheme (GBIS), since 20221.
Age UK reports that routine checks identified the problems with the fitting of internal and external solid wall insulation1. The letter is described as going to households that could potentially be affected, rather than to confirmed cases1.
"Routine checks have identified some quality issues with the fitting of internal and external solid wall insulation under two energy efficiency schemes - the Energy Company Obligation and Great British Insulation scheme, since 2022."
Both schemes were set up to tackle fuel poverty and reduce energy bills by providing help with free or cheaper single insulation measures1. ECO provides help with heating and energy efficiency measures to people in private housing who receive certain benefits, or to those in social housing with a low energy efficiency rating of E, F or G1. Larger energy suppliers must participate in ECO and fund the delivery of these measures1.
The two schemes are at different stages. GBIS ended on 31 March 2026, while ECO is due to end on 31 December 20261.
| Scheme | Status |
|---|---|
| Great British Insulation Scheme (GBIS) | Ended 31 March 20261 |
| Energy Company Obligation (ECO) | Due to end 31 December 20261 |
TrustMark, described as the certification body that oversees the scheme installers, is responsible for a "Find and Fix" service1. Age UK states this can offer a free home audit check of external wall measures installed under these schemes, focusing on the safety and technical standards of the work1. Age UK also states that householders will be able to obtain the Unique Measure Reference Number for their home1. Age UK lists a helpline number, 0800 678 1602, open 8am to 7pm, 365 days a year1.
Why it matters for households
Solid wall insulation is one of the more consequential measures a home can have fitted, because it changes how the building handles moisture and heat at the wall itself. Where the work falls short of technical standards, the household carries the risk: the expected reduction in heat loss may not materialise, and defects can be harder and costlier to put right once the wall has been covered. For a home's energy independence, the value of the measure rests on it performing as designed over decades, not on the fact that it was installed.
The letter concerns measures fitted under schemes funded by energy suppliers, so the household did not necessarily choose or pay for the installer directly. That can leave uncertainty about who is responsible for putting faults right. The Find and Fix route described by Age UK is the mechanism identified for checking external wall measures, and it covers safety and technical standards rather than billing or scheme eligibility1. Households that receive a letter and are unsure whether it is genuine can check the guidance on how to tell if an Ofgem letter about insulation is genuine. The wider picture of faulty installs and remediation is set out in the guide to ECO4 and GBIS insulation failures, and the regulator's remit is covered in what Ofgem does. Complaints routes are explained under energy complaints and redress.
What happens next
GBIS has already closed, and ECO is due to end on 31 December 20261. No deadline for responding to the 65,000 letters, and no completion date for the Find and Fix audits, has been reported.
Sources1 cited
- ECO and GBIS solid wall insulation scheme issues, ageuk.org.uk