Cavity wall insulation is funded now through ECO4, LA Flex and the Warm Homes: Local Grant — not GBIS, whose GOV.UK referral route closed on 31 March 2026. If you receive qualifying benefits and your home is EPC band D or below, ECO4 can cover it in full. No benefits? Your council may still fund it through LA Flex or the Warm Homes: Local Grant (running to March 2028). Every route needs a quick survey first to confirm your walls are suitable. Check which route fits your postcode →Last checked: 18 July 2026
Which schemes fund cavity wall insulation now?
Cavity wall insulation is one of the cheapest ways to cut heat loss, and for eligible homes it is still completely free — just through different schemes now that GBIS has closed.
- ECO4 (on benefits): If you receive Universal Credit, Pension Credit, income-based JSA or ESA, Income Support or Housing Benefit, and your home is EPC band D or below, ECO4 funds cavity wall insulation in full. Runs to 31 December 2026.
- LA Flex (no benefits): Local authorities can refer lower-income or vulnerable households who do not claim qualifying benefits. The rules vary by council.
- Warm Homes: Local Grant: Council-referred funding for lower-income owner-occupiers, covering insulation and low-carbon heating. Runs April 2025 to March 2028.
Not sure which one fits? Check your postcode and we will compare ECO4, LA Flex, Warm Homes and supplier-led routes for you in about a minute.
Is my home suitable for cavity wall insulation?
Most houses built between the 1920s and 1990s have cavity walls — two layers of brick with a gap between them that can be filled. If your external brickwork is laid in an even "stretcher bond" (all bricks the same length), you probably have a cavity. Your EPC certificate also states your wall type.
A survey is required either way. Before any grant work goes ahead, an installer inspects the wall to confirm the cavity is clear, dry and wide enough to fill. Homes with damp problems, very exposed weather-facing walls, or cavities that are too narrow or already partly filled may not be suitable — the survey exists to catch this before installation.
Watch out for scams: ECO4, LA Flex and Warm Homes cavity wall grants are always free to apply for. A genuine installer will never ask you to pay upfront for an "application", a "survey fee" or to "release" your grant. If someone does, stop and check your eligibility through official routes instead.
How Much Does It Save?
- Detached house: up to £595/year
- Semi-detached: up to £395/year
- Mid-terrace: up to £195/year
- Bungalow: up to £295/year
These savings add up to thousands over the life of the insulation, which lasts 25+ years with no maintenance.
What if you are not eligible for a grant? Paying privately, cavity wall insulation typically costs £1,500–£3,000 depending on property size and access — and with savings of up to £595 a year, it usually pays for itself within a few years.
The Installation Process
- Small 22mm holes drilled in external mortar joints
- Insulation material (mineral wool, polystyrene beads, or foam) injected into the cavity
- Holes sealed and colour-matched to your mortar
- Takes 2-3 hours — no internal disruption
Does My Home Have Cavity Walls?
Most homes built between 1920 and 1990 have cavity walls. If all your external bricks are the same length (stretcher bond pattern), you likely have cavity walls. Your EPC certificate also states your wall type.
Check Current Routes
Check your eligibility in 60 seconds for ECO4, LA Flex, Warm Homes and current supplier-led insulation routes.