Home Insulation Costs UK (2026)
What each insulation measure costs, how much it saves each year and how quickly it pays back.
Loft insulation costLoft insulation costs £400–£1,000 in the UK and saves up to £300 a year. Prices by property type and payback in 1–3 years.Cavity wall insulation costCavity wall insulation costs £1,000–£2,500 in the UK and saves up to £450 a year. Prices by house type, payback and suitability.External wall insulation costExternal wall insulation costs £100–£180 per m², or £8,000–£22,000 per house in the UK. See savings and payback by property type.Internal wall insulation costInternal wall insulation costs £50–£110 per m² in the UK, about £6,000–£14,000 per house. Savings, payback and room-by-room options.Double glazing costDouble glazing costs £400–£1,000 per window in the UK, or £4,000–£12,000 for a house. See energy savings and payback by property type.Draught-proofing costDIY draught-proofing costs £100–£250 and a professional job £200–£600. It saves around £50–£125 a year — payback in one to three years.