Free Cavity Wall Insulation Grant UKECO4 & Warm Homes: Local Grant — eligibility, survey & costs 2026

Yes, for many eligible households in England, Scotland and Wales, through ECO4 (to 31 December 2026) or the Warm Homes: Local Grant (to 31 March 2028). Funding is obligation- or allocation-based and isn't guaranteed for every applicant. GBIS closed on 31 March 2026. Northern Ireland is outside both schemes and uses Affordable Warmth instead.

You typically need household eligibility — a qualifying benefit, income under £36,000 for WHLG, or an LA Flex referral — plus a property confirmed suitable on a free technical survey: cavity wall construction, an unfilled or remediable failed fill, and an EPC rating of D–G. Self-diagnosis on suitability isn't enough.

Common qualifying routes include Universal Credit, Pension Credit, Income Support, income-based JSA or ESA, Working Tax Credit and Child Tax Credit. PIP, DLA and Attendance Allowance are not standalone qualifiers — they need to be paired with a means-tested benefit, or accessed through your council's LA Flex route.

Yes, two ways: through the Warm Homes: Local Grant if your household income is £36,000 or less (or you're assessed as cold-vulnerable), or via Local Authority Flexible Eligibility (LA Flex) where your council runs an active Statement of Intent. Not every council runs LA Flex, so confirm locally.

Most UK homes built from the mid-1920s to the early 1990s use cavity construction. Solid wall homes need a different measure. Only a trained surveyor with a borescope can confirm cavity width, debris, existing fill and damp risk.

Under ECO4 or WHLG, the technical assessment checks construction, cavity condition, exposure, ventilation and whether CWI is appropriate. It's provided free as part of the eligibility pathway. Use TrustMark or PAS-aligned installers in the scheme supply chain.

For a typical house, injection through small external mortar-joint holes often takes a few hours to one working day once scheduled. Larger or more complex properties can take longer.

Private CWI commonly falls in the £500–£2,500+ range depending on property size, access and material, with larger or harder-to-access homes costing more. ECO4 or WHLG can cover the full measure cost for eligible, suitable homes, subject to funding.

Correctly specified and installed CWI in a suitable cavity shouldn't cause damp. Problems arise from bridging, debris, driving rain, a failed previous fill, or poor ventilation — which is exactly what the technical survey is there to catch.

Failed fill can leave cold spots or damp patches. Extraction and re-fill is specialist work and isn't automatically free — under ECO4 or WHLG, funding depends on scheme rules and survey evidence.

They treat different heat-loss paths — walls versus roof. Many funded projects install both where the property supports it. The right package is property-specific; see our insulation grant hub for the wider menu.

Yes, if the household meets eligibility and the landlord gives written consent. Never authorise drilling without landlord permission in writing.

ECO4 operates across Great Britain. WHLG is England-only. Scotland has Home Energy Scotland; Wales may combine Nest / Warm Homes support with ECO4. Northern Ireland is outside both — use Affordable Warmth via nidirect.

ECO4 delivery runs to 31 December 2026, per Ofgem guidance, following a nine-month extension. There's no ECO5. From 2027, the wider Warm Homes Plan — already partly live through the Warm Homes: Local Grant — takes over. Always check GOV.UK and Ofgem for the current position.