The two questions every homeowner asks first: what does EWI actually cost, and can I get help paying for it? The honest answers changed in 2026. Here is where things stand.
Most UK cost guides, including Checkatrade and the Federation of Master Builders, currently put installed EWI somewhere between roughly £85 and £150 per square metre, depending on the insulation type, render finish and access. These are prices for privately funded work. If you qualify for a grant-funded installation, costs are handled through the scheme rather than billed to you per square metre. For a typical three-bed semi-detached home, published 2026 guides mostly land between about £9,000 and £14,000 all-in; small terraces can come in under that, larger or more complicated properties above it.
Treat every figure above as a starting point, not a promise. Your property is not an average: wall area, storey height, existing render condition, how much repair work is needed before boards go on, and how many windows and junctions need detailing all move the number, in both directions.
That is why we only give prices in writing after a proper survey. It is also why we would be careful with anyone who quotes a firm price for external wall insulation without seeing the walls.
If you last looked into insulation grants a year or two ago, forget what you read. The schemes you saw advertised have closed or are closing.
The Great British Insulation Scheme ended on 31 March 2026 with no extension. Adverts still promoting it are out of date.
Extended to 31 December 2026, but the government's own response is clear: the extension exists so existing work can be completed. It is effectively closed to most new applicants.
Published March 2026: £15bn committed to upgrading up to five million homes by 2030, delivered largely through council-administered grants targeted at lower-income households and homes with poor EPC ratings.
The era of supplier-obligation schemes with broad eligibility is over. Funding now flows mainly through local councils, aimed at households on lower incomes or in properties with low EPC ratings, where it can be generous, sometimes covering solid-wall insulation in full. Everyone else should plan EWI as a self-funded improvement and judge it on comfort, condition and running costs.
If nobody has measured the walls or looked at the substrate, the number is a guess, and guesses get revised upwards mid-job.
Most of the failed systems we repair failed at sills, reveals and junctions. If the quote doesn't mention them, the job won't either.
“The grant ends Friday, sign today.” Real schemes have published rules and never require an on-the-spot signature.
You should know exactly which boards, which thickness, which render and whose system you are buying. “High-quality insulation” is not a specification.
We survey properly, quote in writing and tell you honestly if a grant route might fit before you spend anything. Comparing quotes you already have? An independent consultation can save you from an expensive mistake.