The short answer
The Great British Insulation Scheme (GBIS) is a UK government-backed scheme that funds single insulation measures — including wall insulation — in homes that need them. Run through energy suppliers and overseen by Ofgem, it is broader than ECO4: alongside a Low Income Group, it has a General Group that reaches households in a lower council tax band with a lower EPC rating (typically D–G), even without means-tested benefits. It funds one measure at a time rather than a whole-house package, so cavity or solid wall insulation can be delivered as a standalone measure. Whether it covers the full cost or a contribution depends on the group and circumstances. Check eligibility on gov.uk; rules are periodically reviewed.
GBIS was designed to widen access to basic insulation beyond the low-income focus of ECO4. Here is how it is structured and who it can help.
GBIS at a glance
- Overseen byOfgem
- Two groupsGeneral, Low Income
- General Group testLower EPC + lower council tax band
- FocusSingle measures
- Sits alongsideECO4
How GBIS differs from ECO4
ECO4 and the Great British Insulation Scheme run in parallel but serve different needs. ECO4 takes a whole-house, fabric-first approach aimed at low-income and vulnerable homes, often delivering several measures to lift a property up the EPC bands. GBIS is deliberately simpler and broader: it funds single measures such as cavity wall, solid wall, loft or room-in-roof insulation, and reaches a wider set of households — including some not on benefits — through its General Group.
| Feature | ECO4 | GBIS |
|---|---|---|
| Approach | Whole-house package | Single measure |
| Main target | Low-income / vulnerable | Broader, incl. General Group |
| General Group test | — | EPC + council tax band |
| Wall insulation | Yes, as part of package | Yes, as standalone measure |
Indicative comparison, 2026. Confirm current rules on gov.uk or Ofgem.
The two groups
GBIS has two eligibility routes. The Low Income Group works much like ECO4, helping benefit-receiving and vulnerable households. The General Group is the wider route: it opens eligibility to homes in a lower council tax band with a lower EPC rating, regardless of benefit status. This General Group is what lets owner-occupiers and renters who would not qualify for ECO4 still get help — though for this group the scheme may provide a contribution towards the cost rather than fully funding the measure.
What GBIS funds and how to apply
Because GBIS funds single measures, an under-insulated wall is one of the things it can pay for, including cavity wall and, in suitable cases, solid wall (external) insulation. The factual route is to apply through the gov.uk 'apply for the Great British Insulation Scheme' service, which checks your EPC and council tax band, or to go through an energy supplier delivering the scheme. If eligible, an approved installer assesses the property, and any work is carried out to PAS 2030/2035 by a TrustMark-registered installer.
It is worth knowing that the General Group's use of EPC and council tax band rather than benefits is what makes GBIS valuable to middle-income households in less efficient homes. As with all these schemes, use official channels rather than doorstep cold-callers, and check the current rules, since scheme details and budgets are reviewed periodically.
How GBIS fits the wider picture
GBIS does not stand alone. It was introduced to run alongside ECO4 and broaden the number of homes that could get basic insulation, so the two are best thought of as complementary. A household on a qualifying benefit might be served by either scheme's low-income route; a household on an ordinary income in a less efficient, lower-band home is the kind GBIS's General Group was designed to reach. When you check eligibility through the official service, the assessment effectively sorts you into the right scheme and group.
For anyone who does not qualify for grant funding at all, the fallback remains favourable: privately paid external wall insulation in Great Britain carries 0% VAT on installed energy-saving materials under the relief running to 31 March 2027, lowering the cost. So most households have a route to better-insulated walls — full or partial grant funding for those who qualify, and VAT-relieved private installation for those who do not. Because scheme budgets and rules change, check the current position rather than relying on older information.
What to expect once you qualify for GBIS
Knowing the practical sequence helps set expectations. After you check eligibility through the gov.uk service or an obligated energy supplier, a qualifying property is booked in for a survey or retrofit assessment, where an assessor confirms the home is suitable for the measure and that installing it will not create problems such as trapped moisture. Because GBIS funds single measures, the focus is narrower than ECO4's whole-house approach — for external wall insulation, the assessor is mainly confirming the walls are solid (or otherwise un-insulated), that the render and detailing can be done correctly, and that ventilation will remain adequate. Where the General Group applies and the scheme part-funds the work, you should be told the contribution you will pay before anything is agreed.
The installation itself is carried out to the PAS 2030/2035 standards by a TrustMark-registered installer, and you should receive a guarantee for the insulation system along with the paperwork recording what was funded. For external wall insulation specifically, this matters: a solid wall system relies on correct detailing around windows, eaves and the damp-proof course, and the PAS framework plus the guarantee are what protect you if anything is wrong later. So while GBIS is the simpler, single-measure scheme, the quality safeguards on the actual EWI work are the same recognised standards used across all the grant routes — which is part of why using the official channels, rather than an unverified doorstep offer, matters as much here as anywhere.
Because GBIS funds a single measure, it is also worth thinking about whether wall insulation is the right first measure for your home, or whether something else — loft or room-in-roof insulation, say — would do more for the same effort. The retrofit assessor can advise on this, but the practical point is that GBIS lets you target the biggest weakness: for a solid-walled home losing most of its heat through the walls, external wall insulation usually is that weakness, which is why it features prominently in the scheme for this type of property.
Frequently asked questions
What is the Great British Insulation Scheme?
GBIS is a UK government-backed scheme, overseen by Ofgem and delivered through energy suppliers, that funds single insulation measures including wall insulation. It reaches a broader group than ECO4 via its General Group, based on EPC rating and council tax band.
How is GBIS different from ECO4?
ECO4 delivers whole-house packages to low-income and vulnerable homes, while GBIS funds single measures and reaches a broader group — including households not on benefits, via its General Group based on EPC and council tax band.
Can I get GBIS help on an average income?
Possibly. The General Group uses your home's EPC rating and council tax band rather than your income, so an average-income household in a lower-band, less efficient home may qualify, though it may receive a contribution rather than full funding.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific property. They are guidance, not a quotation.