Typical 2026 UK costs and savings for the main insulation measures, and how to pay a fair price.
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Insulation is one of the most cost effective home improvements you can make, but prices vary a lot by measure and by home. Here is a clear 2026 overview of what the main types of insulation cost and what they can save, with links to our detailed guides. All figures are typical Energy Saving Trust estimates, so treat them as a guide and compare quotes for your own home.
| Measure | Typical cost | Typical annual saving |
|---|---|---|
| Cavity wall insulation | £950 to £3,900 | Up to about £380 |
| Loft insulation (0mm to 270mm) | £650 to £1,200 | Up to about £360 |
| Loft top-up (120mm to 270mm) | Around £600 | Around £17 |
| Solid wall insulation (external) | £6,000 to £30,000 | Up to about £330 |
| Floor insulation | £70 to £105 per m² | Around £85 |
Cost and saving figures: Energy Saving Trust (England, Scotland & Wales), verified August 2026. These are typical estimates and your own quote will vary by home. Always compare quotes.
For a typical home cavity wall insulation costs around £2,200, ranging from about £950 for a flat to £3,900 for a detached house, and a detached home can save around £380 a year. See the full breakdown by house type in our cavity wall insulation cost guide, or read the complete cavity wall insulation guide for how it works, suitability and damp questions.
Insulating an uninsulated loft to the recommended 270mm costs around £750, while topping up from 120mm to 270mm is around £600. Depth matters more than you might think, so see the full loft insulation cost breakdown, and our guide to loft insulation depth.
Homes built before about 1920 usually have solid walls, which cost more to insulate. External wall insulation runs from around £6,000 for a mid-terrace to £20,000 to £30,000 for a detached house, and can save up to around £330 a year. See the full solid wall insulation cost guide.
Floor insulation is usually priced per m², from around £70 for a solid floor to £105 for a suspended timber floor. Savings are modest, but it makes a cold ground floor much more comfortable. See the full floor insulation cost guide.
The main drivers are the size of your home, how easy the area is to access, the material used and its thickness, and your location. See how the materials weigh up on performance and price in our insulation comparison, and check any spec against Building Regs targets with our free U-value calculator. Grant funding can reduce or remove the cost for eligible homes, and comparing quotes almost always beats accepting the first price.
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It depends on the measure. Cavity wall insulation typically costs around £950 to £3,900 depending on house size, and loft insulation from around £600 for a top up to £750 for an uninsulated loft, based on Energy Saving Trust figures. Solid wall insulation costs more. Comparing quotes is the best way to see a fair price for your home.
Loft and cavity wall insulation are usually the best value because they are relatively low cost and cut a large share of a home's heat loss (around 25% escapes through the roof and a third through the walls). They are the sensible place to start before more expensive measures.
Possibly. Support is changing under the Warm Homes Plan and eligibility varies, so check our 2026 insulation grants guide and confirm current schemes before relying on them.
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Insulation Advice Centre