Compare insulation costs by property type →
What affects the cost?
The two most useful insulation benchmarks for many UK homes are loft quilt insulation and cavity-wall insulation. Current guidance places 270mm loft quilt around £654 for a terraced house, £825 for a semi-detached home and about £1,206 for a detached property. Cavity-wall insulation ranges from about £950 for a flat to £4,600 for a detached home, with glass wool around £25–£30 per m² and polyurethane foam around £30–£65 per m². Suitability should be checked before installation, particularly where damp, exposed walls or existing failed insulation are concerns.
- Loft or cavity-wall insulation
- Property type and measured area
- Existing insulation depth
- Glass wool, mineral wool, EPS or foam specification
- Wall exposure, condition and damp risk
- Access and removal of old insulation
- Repairs identified by the survey
Typical cost breakdown
Home insulation costs by location
Open a detailed city page to see the same national benchmark adjusted through the transparent regional model, with local planning considerations and worked examples.
Sources used for this guide
UK loft and cavity wall insulation cost guidance
Published / checked: Checked September 2026
Used for: Loft insulation property benchmarks and cavity wall per-m² costs
Frequently asked questions
How much does loft insulation cost in 2026?
For 270mm quilt insulation, current benchmarks are about £654 for a terraced house, £825 for a semi-detached home, £1,206 for a detached home and £1,205 for a bungalow.
How much does cavity wall insulation cost?
Current property benchmarks range from about £950 for a flat to £4,600 for a detached property. A semi-detached home is around £2,700 and a mid-terrace around £1,800.
How much is cavity wall insulation per m²?
Current guidance places glass wool around £25–£30 per m² and polyurethane foam around £30–£65 per m².
Should cavity walls be surveyed before insulation?
Yes. A suitability survey should check the wall construction, exposure, damp risk and condition before insulation is installed. Repairs can add to the budget.
Related costs
Cavity wall insulation
Typical UK cavity wall insulation costs by property type and wall area.
£950–£4,600 by property typeView guide →Cost guideExternal wall insulation
UK external wall insulation costs per square metre and by property type.
£150–£200 per m² installedView guide →Cost guideHeat pump
Current UK heat-pump costs for air-to-air, air-to-water and ground-source systems, with 2026 Boiler Upgrade Scheme grant values shown separately.
About £15,000 for air-to-water before grantView guide →