Cavity Wall Insulation
The most popular UK insulation. Quick install, big savings. Often free with ECO4 grant
Get Free Quotes from InstallersWhat is Cavity Wall Insulation?
Most UK homes built after 1920 have cavity walls - two layers of brick with a gap (cavity) between them. Cavity wall insulation fills this gap with insulating material, stopping heat escaping through your walls.
Installation takes just 2-3 hours and can save you £100-£400 per year on heating bills. It's the quickest, most cost-effective insulation upgrade available and is often fully funded through ECO4 grants for eligible homes.
Why Choose Cavity Wall Insulation?
Often Free
ECO4 grant covers full cost for eligible households
Quick Install
Completed in 2-3 hours with minimal disruption
Big Savings
Save £100-£400/year on heating bills
Warmer Home
Reduce heat loss by up to 35%
No Mess
Installed from outside - no internal work needed
Long Lasting
Lasts 40+ years with 25 year guarantee
How Installation Works
Survey
Check cavity suitability and take measurements
Drill Holes
Small holes drilled in mortar at regular intervals
Inject Material
Insulation pumped into cavity through holes
Fill & Finish
Holes filled to match existing mortar
Cavity Wall Insulation Costs
ECO4 Grant - Often FREE!
If you receive benefits or have income under £36k and EPC D-G, installation is often completely free through ECO4
Quick Grant Finder
Answer 3 quick questions to see which grants you may qualify for
Is Your Home Suitable?
✓ Suitable Homes
- Built after 1920 with cavity walls
- Cavity at least 50mm wide
- No existing cavity insulation
- Walls in good condition
⚠ Not Suitable
- Solid wall homes (pre-1920)
- Already has cavity insulation
- Cavity narrower than 50mm
- Exposed/severe weather locations
Note: These homes need solid wall insulation instead
Ready to Insulate Your Walls?
Get free quotes from certified installers. Often completely free with ECO4 grant
Get Free Quotes from Installers