Get help with faulty solid wall insulation

Your solid wall insulation might be faulty if you used one of the following government schemes:

• Energy Company Obligation (ECO4) 

• Great British Insulation Scheme (GBIS)

If it’s faulty you might get problems like damp or mould. You might be able to get it checked and fixed for free.

Check which scheme you used

If you used either ECO4 or GBIS, Ofgem might have sent you a letter. This letter would tell you if your solid wall insulation might be faulty.

You might have used ECO4 or GBIS if both of the following apply to you:

• the work on your solid wall insulation was carried out between April 2022 and January 2025

• you got help with the cost of the work

If you’re still not sure, contact Ofgem.

If you used ECO4 or GBIS

You’ll be contacted and offered a free home check.

You might get a letter from Ofgem or Trustmark. The letter will quote your ‘unique measure reference’ number, so you know it’s genuine.

Or you might have someone from Trustmark knock on your door. You should ask for their ID and ‘unique measure reference’ number to check they’re genuine.

If you have not been contacted or you’re worried about being scammed you can contact TrustMark to arrange the check.

During the home check, a qualified professional will look at the insulation to see if it was installed correctly. This is for wall insulation installed inside and outside your home.

If they find any problems, TrustMark should get an installer to fix them. You will not have to pay anything.

If you’re worried about an installer coming back to your home, contact Trustmark for what to do next.

You can find other ways to get in touch with TrustMark on their website.

Contact the Citizens Advice consumer service if you need more help - a trained adviser can give you advice over the phone or by online chat.

If you didn’t use ECO4 or GBIS

You might still be able to get your solid wall insulation fixed for free. Check how to complain about an energy efficiency home improvement.