Which? responded on 14 October 2025 to a National Audit Office report on faulty insulation, describing the scheme as failed and its oversight as poor. Sue Davies, Which? Head of Consumer Protection Policy, said rogue traders had been allowed to cause damage to homes and lives1.
"This is a damning indictment of a failed scheme, where poor oversight has allowed rogue traders to cause huge damage to people's homes and lives."
Davies said schemes of this kind have a critical role in tackling fuel poverty and improving the warmth and comfort of homes, and called on the government to act quickly to rectify the damage done to every affected household1. She also called for robust consumer protections and effective oversight to ensure there is no repeat of what she termed a scandal1.
Which? further said the government should learn wider lessons, so that all households having insulation work done can be confident their installers are properly qualified and able to resolve any issues that arise1. The statement does not name the scheme, the number of affected households, the cost of remediation or a timetable for action; none of these has been reported in the statement1.
Why it matters for households
Insulation is one of the main ways a home reduces heat loss and cuts how much energy it must buy, so the quality of the installation directly affects running costs and comfort. Where work is faulty, the household can be left with the expense of putting it right, and with cavity wall insulation problems the route to a remedy usually runs through the installer's guarantee or a claim. Which? frames the issue as one of oversight: its concern is that poor checking allowed unsuitable traders into the scheme in the first place1.
For households weighing up grant-funded work, the statement points to two things that bear on energy independence: whether the installer is properly qualified, and whether there is a clear route to resolve problems afterwards1. The failures described sit within the Great British Insulation Scheme and ECO4 landscape, where eligibility and installer standards differ between programmes; the ECO4 and GBIS insulation failures page sets out how remediation has been handled. Which? does not, in this statement, say which scheme the NAO examined, nor how many homes are affected1.
What happens next
Which? has called on the government to rectify the damage done to every affected household, to put robust consumer protections and effective oversight in place, and to ensure installers are properly qualified and able to resolve issues1. No deadline, funding figure or mechanism for that remediation appears in the statement, and no government response to the NAO report is reported here1.