Comprehensive guides to insulating your UK home. Cavity wall, loft, external wall, and underfloor insulation costs, savings, and DIY vs professional installation.
209 articles
Internal wall insulation methods cost £40–£100 per m² depending on the type: PIR boards offer highest thermal performance per thickness, insulated plasterboard is quickest to install, and vapour-permeable systems best…
Loft insulation for a standard 3-bed semi costs £300–£700 professionally installed. It saves £200–£300 yearly on heating bills with a 2–4 year payback, making it the cheapest whole-house energy measure.
Insulating a 1930s home typically costs £2,000-£13,000, depending on the measures. The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows…
Hempcrete insulation costs £35–£50 per square metre installed in 2026, making it 40–70% more expensive than mineral wool. It delivers a U-value of 0.18 W/m²K at 300mm thickness and can…
Cavity-wall insulation pays back in 2.5 years, and loft insulation in under 18 months for a semi-detached home. Solid-wall insulation takes longer but grants can cut payback to under 5…
The biggest insulation contractor red flag in UK 2026 is a lack of valid MCS certification. Always verify the certificate number on the official MCS Installer Database before signing any…
Insulating a listed building is legally possible but requires Listed Building Consent under the 1990 Act. Standard cavity-wall or external-wall insulation is routinely refused because it alters the building’s character…
Most UK homes do not need planning permission for EWI – it is permitted development. However, if your property is listed, in a conservation area with projection over 150mm, or…
IWI breathability UK means using vapour-open materials like wood fibre or calcium silicate to avoid moisture damage. Solid-wall homes pre-1919 must prioritise breathability to prevent rot and mould, which can…
Cavity wall insulation removal costs £1,200–£3,500 for a typical three-bed semi-detached house. The price varies by insulation type and property size, with foam removal being more expensive than mineral wool.
Spray foam insulation costs £2,200-£3,500 for a typical 3-bed semi loft in 2026, versus £800-£1,500 for mineral wool. However, HFC-based products with a GWP over 150 are now banned under…
PIR insulation costs £15-£25 per m² in 2026, with a lambda value of 0.018-0.022 W/mK, making it 30-40% more efficient than EPS. It's the top choice for meeting Part L…
Insulation materials UK 2026 cost £10-£50 per m². Mineral wool is cheapest at £10-£20 per m² for lofts, while PIR boards offer best thermal performance at £25-£50 per m² for…
U-values measure heat loss in W/m²K; lower is better. A 0.30 wall saves £250-£350 a year vs uninsulated. Legal limits for new builds in 2026 are walls 0.18, roofs 0.11,…
The recommended loft insulation thickness for 2026 is 270 mm for mineral wool, targeting a U-value of 0.16 W/m²K. Other materials like PIR boards need less depth to meet the…
Floor insulation costs £500–£2,200 in 2026, with suspended timber floors at the lower end and solid concrete floors at the higher end. Annual savings range from £50–£150, and payback is…
Solid wall insulation is worth it for most eligible UK homes in 2026, saving £200 to £400 per year on heating bills according to Energy Saving Trust figures. The Great…
External wall insulation costs £8,000–£22,000 for a semi-detached house in 2026, saving £190–£400 per year on gas bills. The payback period is 25–50 years, so it suits long-term homeowners more…
Internal wall insulation costs £40–£120 per m² in 2026, with a typical 3-bed semi totalling £2,500–£8,000. Annual savings of £200–£600 on energy bills mean a payback period of 8–15 years…
Cavity wall insulation UK 2026 costs £500-£1,200, but most households pay nothing through the Great British Insulation Scheme. Annual savings average £225 for a semi-detached home with gas central heating.
Loft insulation costs £400-£1,200 to install in 2026, and a typical semi-detached home saves £590 per year on energy bills. Payback takes just 1.0-1.6 years. The Great British Insulation Scheme…
DIY internal wall insulation is possible in the UK, but poor fitting can cut thermal performance by 50%. Here's when to do it yourself and when to hire a pro.
The UK recommends 270mm of mineral wool loft insulation, meeting a 0.16 W/m²K U-value. Topping up from under 100mm pays back in under 3 years.
Loft insulation lasts 40+ years in the UK, but damp or compression can cut that to 10–20 years. Check if your depth meets the 270 mm standard.
Cavity wall insulation typically costs 500 to 1,500 pounds for a standard three-bedroom semi-detached house. The exact cost depends on the size of your home and accessibility. It can save around 150 to 250 pounds per year on heating bills, giving a payback of 3 to 6 years.
The recommended thickness for loft insulation in the UK is 270mm of mineral wool or equivalent. Many older homes have only 100mm or less. Topping up existing insulation to the recommended depth is one of the cheapest and most effective energy improvements you can make.
External wall insulation costs 8,000 to 15,000 pounds but can save 200 to 400 pounds per year on heating bills. It also improves comfort, reduces condensation risk, and can transform the appearance of your home. Grants through ECO4 or the Great British Insulation Scheme may cover part of the cost.
You can DIY loft insulation and basic draught proofing, which are straightforward projects. However, cavity wall insulation, external wall insulation, and underfloor insulation should be installed by certified professionals to ensure effectiveness, building regulations compliance, and warranty coverage.
Check your EPC certificate which will state whether cavity wall insulation is present. For a physical check, a professional can drill a small hole in the wall and use a borescope to inspect the cavity. Homes built after 1990 are likely to have insulation fitted during construction.
UK home insulation costs range from £300-£500 for loft insulation saving £200-£300 per year, to £500-£1,500 for cavity wall insulation saving £200-£400 per year. The Great British Insulation Scheme closed…
The recommended loft insulation thickness in the UK is 270mm of mineral wool for a standard cold loft, as specified under Part L of the Building Regulations and endorsed by…
External wall insulation in the UK costs between £80 and £200 per square metre installed in 2026, with whole-house projects typically ranging from £8,000 to £25,000 depending on property size,…
Insulating a solid wall house internally is a highly effective way to cut heat loss in older UK properties, where uninsulated solid walls can account for up to 35% of…
Underfloor insulation for a suspended timber floor involves fitting insulating material, most commonly mineral wool batts or rigid foam boards, between the timber joists in the void beneath your ground…
Internal wall insulation for period properties involves fixing insulating boards or natural materials to the inside face of solid brick or stone walls, preserving the exterior appearance while reducing heat…
