INSULATION GUIDE
Insulation Grants UK 2026: Free Loft, Cavity Wall & ECO4 Routes
Three live insulation grants can cover the cost of loft, cavity wall, and solid wall insulation in 2026.
Check eligibilityLast updated May 2026
Three live insulation grants can cover the cost of loft, cavity wall, and solid wall insulation in 2026.
Answer a few quick questions to see which government energy grants you're eligible for. Free, instant results.
Eligibility at a glance
Free eligibility check
Three grants currently fund free or subsidised insulation: ECO4, the Warm Homes Local Grant, and ECO4 Flex. The Great British Insulation Scheme closed to new applications in March 2026.
The routes work differently. ECO4 is the largest, administered by every major UK energy supplier under Ofgem regulation, and it pays for full insulation upgrades for households on qualifying benefits. The Warm Homes: Local Grant, part of the government's £15 billion Warm Homes Plan, runs through individual councils and targets households earning under £36,000. ECO4 Flex is the same scheme as ECO4 but uses council-set income criteria instead of benefits.
Every one of these routes can fund loft, cavity wall, and solid wall insulation, with some also covering underfloor insulation and room-in-roof insulation. None of them require you to pay anything upfront if your installer is approved under the scheme.
home energy measures funded through ECO4 since 2022, with insulation the most common
If your home is already rated EPC C or above, you generally won't qualify for any of these routes. The schemes target the worst-rated properties because that's where the policy delivers the most carbon and bill savings. Our EPC ratings guide covers how to read your certificate and what counts as a qualifying band.
You qualify if you receive certain benefits, your home is rated EPC D to G, and your property is suitable for the works.
Qualifying benefits
Universal Credit, Pension Credit (Guarantee or Savings Credit), Child Tax Credit, Working Tax Credit, Income Support, Income-based JSA, Income-related ESA, Housing Benefit or Child Benefit (with income limits). Only one household member needs to claim.
EPC band D, E, F or G
Homes already at band C or above don’t qualify. If your last EPC expired more than 10 years ago, an assessor can issue a new one as part of the survey.
Owner-occupied or privately rented
Landlord consent is required for rented properties, but a tenant’s benefit status triggers eligibility. Social housing tenants apply through their housing association instead.
Property suitable for the works
Some homes can’t take cavity wall insulation (timber-frame, single-brick, or steel-frame construction). The installer’s survey confirms what’s technically possible.
Whole-house approach
ECO4 requires homes to reach EPC band C after the works where possible. That means insulation often comes bundled with heating controls, draught-proofing, or a new boiler.
The eligibility checker runs your details against ECO4, ECO4 Flex and your council’s Warm Homes Local Grant in 2 minutes.
The whole-house rule is what trips most people up. ECO4 isn't a single-measure scheme any more. If your loft has 100mm of insulation but your walls are uninsulated, the installer is expected to assess the property as a whole and propose the package that gets you to band C. That sometimes means insulation funded alongside a new boiler or new heating controls. It also means the assessor might recommend external wall insulation rather than cavity, depending on construction type.
If you don't claim benefits but your household income is low, ECO4 Flex is your route. Each council sets its own income threshold, typically around £31,000 to £35,000 combined household income. Some councils require an additional qualifying factor: a child under five, a household member with a long-term health condition, or a property in the bottom 25% of EPC ratings locally.
Your situation
On qualifying benefits with EPC band D-G
Best route
ECO4 via your energy supplierYour situation
Household income under £36,000 with EPC D or below
Best route
Warm Homes: Local Grant via your councilYour situation
Low income but no qualifying benefits
Best route
ECO4 Flex via your councilYour situation
Pensioner on Pension Credit
Best route
ECO4 + Warm Home DiscountYour situation
Social housing tenant
Best route
Apply through your housing associationECO4 funds loft, cavity wall, solid wall, underfloor, and room-in-roof insulation, plus draught-proofing and heating controls as part of a whole-house package.
The most commonly funded measures are loft insulation top-ups (bringing existing insulation up to 270mm), cavity wall insulation for properties built between 1920 and 1995, and solid wall insulation for older properties without cavities. Solid wall insulation is the most expensive measure ECO4 funds. External wall insulation typically costs £8,000 to £15,000 privately, and ECO4 covers the lot if your home qualifies.
Room-in-roof insulation is the quietly transformative one. If your loft has been converted into a bedroom or office, the sloping ceilings often have minimal insulation behind them. ECO4 funds proper retrofit insulation in these spaces. That can save more energy than a loft top-up because converted lofts have larger heat-loss surfaces.
Spray foam insulation is not funded under ECO4 and can actually disqualify your home from receiving other measures. Some lenders also refuse to mortgage properties with spray foam in the roof, so be cautious if you've been pitched it by a cold-caller.
What ECO4 doesn't fund: spray foam, blown bead in unsuitable cavities, or any measure on a property already rated EPC C or above. The Energy Saving Trust publishes detailed insulation guidance on what works and what doesn't for different property types.
Loft insulation costs £400 to £800 to install privately. Cavity wall is £400 to £1,500. Solid wall is the expensive one at £8,000 to £15,000.
These figures are for a typical three-bedroom semi-detached home with no access issues. Costs scale with property size and complexity. A detached four-bedroom house with a steep pitched roof and limited loft access will sit at the top of the loft range; a small terraced house with easy access sits at the bottom.
The gap between the loft figure and the solid wall figure is why ECO4 prioritises solid wall work for the lowest-rated homes. A solid-walled Victorian terrace at EPC band F probably loses 40% of its heat through the walls. Insulating those walls under ECO4, at no cost to the household, is one of the biggest single interventions available in UK domestic energy policy.
For homeowners who don't qualify for any grant, materials and labour for DIY-friendly loft insulation can be bought for £200 to £400 from any builder's merchant. It's one of the few home upgrades where the DIY option genuinely makes financial sense, provided the loft is empty and the ceiling joists are accessible.
Start with the eligibility checker, then book a free assessor visit. The whole process typically takes 4 to 10 weeks from initial enquiry to completed installation.
Confirms benefits status, EPC band, and which scheme applies to your postcode.
An approved installer or assessor visits to verify your details, check existing insulation, and confirm what’s technically possible.
Required under ECO4. The assessor proposes the full package needed to reach EPC band C where possible.
For ECO4, you can apply through an MCS-certified installer, an approved comparison service, or directly through an energy supplier. The supplier matching happens automatically based on which one has remaining annual obligation capacity in your area. You don't choose your supplier.
For the Warm Homes: Local Grant, you apply through your council. Coverage varies considerably. GOV.UK's Warm Homes Plan page lists which councils have funding awarded; check yours before applying. Some councils are running tight schemes with quick turnaround. Others have larger budgets and longer waiting lists.
For ECO4 Flex, the route is also through your council. Each council publishes its own eligibility criteria and application form. The advantage of Flex over the main ECO4 route is that you don't need to be on benefits, but the disadvantage is that not every council participates.
Warning signs to watch for
Legitimate insulation grant installers don’t cold-call, charge upfront fees, or pressure you to sign on the day. If you encounter any of the following, walk away:
The insulation grants market has a particularly bad cold-caller problem because the work is profitable and the targets (older homeowners, lower-rated properties) are often easier to identify from public data. The reputable installers don't need to cold-call. Always check that an installer is registered with the TrustMark scheme before agreeing to any work, and never pay anything upfront for a grant-funded installation.
Two routes remain: pay privately at market rates, or check whether 0% VAT relief on energy-saving materials applies to your installation.
Best for
Low-income households without qualifying benefits
What it funds
Full insulation package (same as ECO4)
Main catch
Each council sets its own income threshold; not all councils participate
Runs until
December 2026
Best for
Households earning under £36,000 with EPC D or below
What it funds
Insulation, heat pumps, or both, with amounts varying by council
Main catch
Council-administered with varying budgets and waiting lists
Runs until
31 March 2028
The 0% VAT relief is the most under-used benefit in UK home energy policy. If you're paying privately for insulation, your installer should be applying 0% VAT to the entire installation cost (materials and labour), not just the materials. If they're charging you 20% VAT, challenge it. The relief was introduced in April 2022 and runs to March 2027.
For older homeowners specifically, our insulation grants for pensioners guide covers the combined Pension Credit and ECO4 route that often qualifies even where income looks middle-band on paper.
Loft Insulation UK 2026
Costs, grants, and DIY options for the most cost-effective home upgrade.
Read guideCavity Wall Insulation UK 2026
What it costs, who qualifies for free installation, and when it’s a bad idea.
Read guideExternal Wall Insulation UK 2026
The biggest single insulation upgrade ECO4 funds, and what to expect from the install.
Read guideECO4 Scheme Guide
How ECO4 works, who administers it, and what it funds beyond insulation.
Read guideCommon questions
Your situation
None of the above
Best route
Pay privately or check 0% VAT relief on materialsYour case is submitted to whichever energy supplier or council fund has remaining capacity.
Loft insulation is one day. Cavity wall is one day. External wall insulation is 1-3 weeks depending on property size.
Best for
Homeowners paying for insulation privately
What it saves
20% off the total cost of qualifying energy-saving materials
Main catch
Installer must apply the relief; some try to charge full VAT anyway
Runs until
March 2027