Fill the Gap and Keep the Heat In
What is cavity wall insulation? It is a process of filling the gap between the inner and outer wall leaves of your property with insulating material. Around 35% of a home's heat can be lost through uninsulated cavity walls. Most UK homes built after the 1920s are suitable. When the cavity is left empty, it allows cold air to circulate and heat to escape. The benefits of cavity wall insulation include significantly reduced heat loss, lower energy bills, and the ability to improve EPC with cavity wall insulation as a key measure.
Installation is straightforward, usually completed in a few hours by drilling small holes into the external wall, injecting insulation material, and making good the holes afterwards. Cucumber Eco manages the full process, from eligibility check through to a completed, warranted installation.
Check Your Eligibility
What the Installation Involves
Cavity wall insulation is installed by injecting mineral wool, polystyrene beads, or other approved insulation material into the wall cavity through small holes drilled from the outside:
- ✓ Small holes are drilled at regular intervals across the external wall
- ✓ Insulation material is injected into the cavity under controlled conditions
- ✓ Holes are filled and the wall surface is made good
- ✓ The process typically takes two to four hours for a standard semi-detached house
- ✓ A guarantee is issued on the installation for added peace of mind
Impact on Your EPC Rating
Wall insulation is one of the largest contributors to a property's SAP score and EPC rating. Uninsulated cavity walls are flagged as a key improvement on most EPC reports for post-1920s properties. Addressing this can:
- ✓ Move a property up by one or more EPC bands
- ✓ Significantly improve the SAP (Standard Assessment Procedure) score
- ✓ Help landlords meet the EPC C minimum target required under proposed MEES regulations
- ✓ Reduce the heating demand figure that lowers overall energy efficiency ratings
Is Your Property Suitable?
Cavity wall insulation is suitable for most UK homes built after around 1920 that have unfilled cavity walls. The following factors typically indicate suitability:
- ✓ Property built after approximately 1920
- ✓ Brick or block external walls with an air gap between layers
- ✓ Cavity is at least 50mm wide and in good condition
- ✓ No significant damp or structural issues with the walls
- ✓ Exposed to moderate rather than severe driving rain
Properties with solid walls, or those in severe exposure zones, may be better suited to internal or external wall insulation. Our surveyors will advise on the best approach for your specific property.
Typical Savings
Based on a typical semi-detached house with uninsulated cavity walls. Actual savings depend on property size, wall construction, heating system, and energy tariff.
Grant Funding and Finance Options
Cavity wall insulation is one of the most commonly funded measures under the Warm Homes Plan. Where eligibility criteria are met, the installation can be fully funded at no cost to the homeowner or landlord. Eligibility is assessed on the basis of:
- ✓ Household income or benefit status
- ✓ Property postcode (low-income area criteria)
- ✓ Current EPC rating of the property
- ✓ Property construction and wall type
Where grant funding is not available, 0% interest finance may be an option through our approved lending partners, subject to eligibility.
Apply for FundingGet a Free Assessment
We will assess your property and eligibility at no cost and with no obligation.