ECO and GBIS solid wall insulation scheme issues

The Energy Company Obligation (ECO) scheme and the Great British Insulation Scheme (GBIS) intended to help better insulate homes and reduce energy bills. However, some issues have been identified with the quality of the insulation, which could affect up to 65,000 households. 

What is the Great British Insulation Scheme?

The Great British Insulation Scheme (GBIS) was a Government energy efficiency scheme that sought to tackle fuel poverty and reduce energy bills by providing help with free or cheaper single insulation measures.

This scheme ended on 31 March 2026.

What is the Energy Company Obligation?

The Energy Company Obligation (ECO) scheme provides help with heating and energy efficiency measures, such as insultation, to those living in private housing who receive certain benefits, or those who live in social housing with a low energy efficiency rating (E, F or G.) Larger energy suppliers must participate in ECO and fund the delivery of these measures, to help customers reduce their energy usage.

The ECO scheme is due to end on 31 December 2026.

What is the issue?

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. This has included:

• missing or incomplete paperwork
• insufficient ventilation
• missing or exposed insulation

What is being done to tackle this issue?

The energy regulator, Ofgem, has written to 65,000 households who could potentially be affected by this issue (although not all of these will necessarily need remedial work to be carried out.)

Trustmark (the certification body that oversees the scheme installers) is responsible for a ‘Find and Fix’ service to help identify and rectify ECO and GBIS insulation problems. They should contact affected households to offer a free home audit check of external wall measures installed under these schemes, focusing on the safety and technical standards of the work. If problems are identified, they should arrange for any necessary repair work to be carried out by the installer as soon as possible, at no cost to the household.

You will know that the Trustmark contact is legitimate because they will be able to provide you with the Unique Measure Reference Number for your home. This is a unique number, just for your home, and it appears on the letter you received from Ofgem.  Only legitimate parties have access to this number. 

If someone contacts you about a home audit check and cannot provide you with this Unique Measure Reference Number, do not share any personal details with them or let them into your home. If you are still unsure, contact Trustmark directly.