Insulation Grants Wales 2026 – What You Can Get and Who Qualifies
Insulation is the cheapest energy saving measure per pound spent, and in Wales it is the measure most likely to be funded in full. Two schemes do the heavy lifting, and the same eligibility tests that unlock free insulation usually unlock solar panels and a new heating system at the same time.
Which Insulation Grants Are Available in Wales?
| Scheme | Who runs it | What it covers | What you pay |
|---|---|---|---|
| Warm Homes Nest | Welsh Government | Loft, cavity wall, solid wall and underfloor insulation, plus heating and often solar | Nothing, for eligible households |
| ECO4 | Energy suppliers, UK wide | A whole house package, insulation first, then heating and renewables | Nothing, or a small contribution |
| Green Homes Wales | Development Bank of Wales | Insulation, heating, solar and battery storage | Interest free loan up to £25,000 |
| Local authority flexible eligibility | Your council, under ECO4 | Same measures as ECO4 | Nothing, referral based |
Who Qualifies for Free Insulation in Wales?
Warm Homes Nest is the Welsh route and the one to try first. It considers low household income, and it also considers whether someone in the home has a health condition made worse by living in a cold house, which is a test that catches households that fall outside benefit based schemes. ECO4 is the UK wide route and is tied to qualifying means tested benefits, or to a local authority referral under flexible eligibility. In both cases the property normally needs a poor EPC rating, typically band D or below for owner occupiers.
What Does the Insulation Actually Involve?
Loft insulation
The quickest win. Topping up from a typical 100mm to the current 270mm standard takes a few hours and is almost always fully funded where a household qualifies. If your loft has never been done, this is where the survey will start.
Cavity wall insulation
Suitable for most houses built after roughly 1920 with a gap between the inner and outer leaf. In exposed coastal and upland parts of Wales, surveyors are rightly cautious about wind driven rain, so a property may be assessed as unsuitable. That is a technical judgement, not a rejection of your application.
Solid wall insulation
Wales has a high proportion of solid wall stone and brick housing, particularly in the valleys and older rural villages. Internal or external wall insulation is the most expensive measure by some distance, which is exactly why it is worth applying for rather than paying for.
Underfloor insulation
Common in older properties with suspended timber floors and often overlooked. Included in Nest and ECO4 packages where the floor construction allows access.
Insulation and Solar Work Better Together
Insulation lowers how much energy the house needs, solar lowers what you pay for the energy it still uses. Both schemes are designed as whole house programmes for that reason: ECO4 in particular requires insulation to be addressed before renewables are funded, so an application that starts with a loft can finish with panels on the roof. If you are looking at solar as well, see our solar panel grants Wales guide, free solar panels in Wales and the ECO4 scheme.
Other Welsh Home Improvement Grants
The same schemes commonly fund a first time central heating system, a boiler replacement, heating controls and, under Nest, energy efficient windows and doors where they are the barrier to a warm home. Grants are assessed as a package rather than item by item, so it is worth asking about everything the property needs in one go rather than applying repeatedly.