Quick answer: A typical insulation project — such as topping up a loft or filling cavity walls — costs a modelled UK average of £1,498 in July 2026, with a range of £974 to £2,322. At up to £381 a year in estimated savings, its modelled payback of around 4 years is among the fastest in our index.
Pound for pound, few other upgrades we model come close. This page sets out the insulation numbers from our UK Home Energy Cost Index; for choosing between loft, cavity and solid-wall measures, see the insulation guide — and the U-value glossary entry explains the key performance measure.
Key insulation statistics for 2026
- A typical insulation project costs a modelled UK average of £1,498 — Green Reach Energy Cost Index, July 2026 (modelled).
- Most insulation jobs fall between £974 and £2,322 depending on measure and property size — Green Reach Energy Cost Index, July 2026 (modelled).
- Insulation is the third-cheapest upgrade in our eight-product index — about a quarter of the cost of solar — Green Reach Energy Cost Index, July 2026 (modelled).
- London insulation projects average a modelled £1,798; Northern Ireland just £1,378 — Green Reach Energy Cost Index, July 2026 (modelled).
- The most-to-least expensive regional gap is £420 — Green Reach Energy Cost Index, July 2026 (modelled).
- North West and Yorkshire households both average £1,423, 5% below the national figure — Green Reach Energy Cost Index, July 2026 (modelled).
- Better insulation could save a typical household up to £381 a year (estimate) — Green Reach Energy Cost Index, July 2026 (modelled).
- Modelled simple payback is around 4 years — among the fastest of any upgrade we track, behind EV chargers and infrared panels — Green Reach Energy Cost Index, July 2026 (modelled).
- Insulation’s modelled annual saving (£381) is over 80% of a heat pump’s (£452) for less than a seventh of the pre-grant cost — Green Reach Energy Cost Index, July 2026 (modelled).
- Insulation carries 0% VAT until March 2027 — GOV.UK, checked July 2026.
- The Warm Homes: Local Grant offers up to £15,000 for insulation (within a £30,000 per-home cap) for eligible households, open to March 2028 — GOV.UK, checked July 2026.
- With gas at 7.33p/kWh under the July–September 2026 Ofgem price cap, every kWh of heat your insulation keeps in is money not spent.
Insulation costs by UK region
Insulation is labour-heavy work, so regional wage differences show up clearly. Note these are averages across common measures — a loft top-up sits below them, external solid-wall insulation far above.
| Region | Modelled average installed cost | vs UK average |
|---|---|---|
| UK average | £1,498 | — |
| London | £1,798 | +20% |
| South East | £1,678 | +12% |
| East of England | £1,588 | +6% |
| South West | £1,573 | +5% |
| West Midlands | £1,468 | −2% |
| East Midlands | £1,453 | −3% |
| Scotland | £1,438 | −4% |
| Yorkshire & the Humber | £1,423 | −5% |
| North West | £1,423 | −5% |
| Wales | £1,408 | −6% |
| North East | £1,393 | −7% |
| Northern Ireland | £1,378 | −8% |
All modelled figures on this page come from the Green Reach Energy Cost Index — our July 2026 estimates built from national installed-price baselines and regional labour indices, not quotes for your specific home. Real insulation prices vary with property type, spec and installer, so treat these as a starting point and read how we calculate costs for the full method and its limitations.
Grants and VAT relief
Insulation is one of the best-supported upgrades. The Warm Homes: Local Grant can fund insulation worth up to £15,000 for households in EPC D–G homes with income under £36,000 — free, and open to March 2028. All insulation also carries 0% VAT until March 2027. The Great British Insulation Scheme, however, closed on 31 March 2026, so check the current grant list before assuming an older guide still applies.
Use the savings calculator to see what insulation could knock off your own heating bill at today’s cap rates.
Download the dataset
The full Cost Index — 9 upgrades × 12 UK regions, July 2026 — as CSV: gre-cost-index.csv. Free to reuse with attribution (CC BY 4.0) — please credit Green Reach Energy and link the methodology. Figures are modelled estimates, not quotes.