How We Calculate This
Source values are drawn from Great Britain examples published by Energy Saving Trust.
INSULATION COST & SAVINGS CALCULATOR
Could Better Insulation Make Your Home Warmer for Less?
Compare insulation types, example installation costs, possible heating-bill savings and practical next steps for your home.
✓ Clear Installation Costs✓ Heating-Bill Examples✓ Comfort & Carbon Context
Tell Us About Your Home
Choose an insulation improvement and tailor the example figures. These reference cases are not property-specific heat-loss assessments.
1. Choose an Improvement
Do not assume your wall or floor construction. An appropriate survey is required before work.
Existing insulation substantially affects how much improvement is possible.
2. Estimate Installation Costs
Editable. A professional quote is more reliable.
Enter £0 unless you have confirmed an award. No grant is assumed.
3. Heating Assumptions
The reference savings model is restricted to mains gas heating. For other fuels, figures are withheld rather than applying an inappropriate gas-cost assumption.
Editable example; check your tariff. Used to scale the reference bill-saving scenario.
100% uses the reference saving; lower/higher values are hypothetical scenarios, not predictions.
Review the Reference Assumptions
The examples reflect typical Energy Saving Trust guidance for Great Britain, not personalised performance estimates.
Change the assumption factor or installation price for your circumstances. Scaling a reference saving cannot replace an EPC or a suitable assessment.
✓ Results Update Automatically
Your Estimated Results
Insulation Scenario Assumptions
Check suitability, existing insulation, moisture, ventilation, building regulations and installer guarantees. These are reference estimates—not a professional assessment.
Example Installation Cost—Before any confirmed funding
Illustrative Annual Heating Savings—Based on the selected published reference and your adjustments
Net Upfront Cost—Installation less confirmed funding only
Carbon Impact—Illustrative gas-emissions equivalent, not a verified reduction
POSSIBLE ANNUAL SAVINGS—
SIMPLE PAYBACK—
No inflation, maintenance or future fuel-price changes included.
Illustrative Cumulative Savings Over 25 Years
Constant annual savings compared with net upfront cost. Not a lifetime financial forecast.
Cumulative savings Net upfront cost
What These Results Mean
Select an insulation improvement to see a practical explanation.
Check Suitability Before Proceeding
An installer should assess existing insulation, ventilation, damp and suitability before work begins.
Suggested Next Steps
- Check Your EPC & Construction
- Get a Suitable Insulation Survey
- Compare Itemised Quotes
- Verify Funding & Guarantees
Comfort & Practical Benefits
Correctly selected insulation can reduce draughts and cold surfaces and improve winter comfort. Outcomes depend on the construction and installation quality; moisture and ventilation must be assessed.
Do not seal essential ventilation openings or assume cavity walls are suitable for filling.
Official Guidance
Methodology, Suitability & Limitations
The cost and yearly bill-saving references are typical Energy Saving Trust examples and are not linked to this property's dimensions, insulation thickness, heating pattern, fuel efficiency or existing heat-loss profile. The calculator uses the reference annual bill-saving value, scales it with an editable percentage and an editable gas tariff relative to 7.97p/kWh, and calculates simple payback from installation cost less only confirmed funding.
The carbon indicator uses illustrative bill savings divided by the selected gas price to estimate equivalent mains gas kWh, multiplied by the UK 2026 0.18231 kg CO₂e/kWh gas reporting factor. This is a rough energy-bill-to-fuel proxy, not independently verified energy saved or a building's measured emissions reduction. It is unavailable for other heating types. Insulation can also change how households heat their home (comfort rebound).
Only suitable insulation should be installed. Ask about moisture, ventilation, building regulations, fire safety, protected buildings, guarantees and installer qualifications. Savings between separate insulation measures are not additive; combined retrofit improvements need an integrated whole-house assessment. Simple payback is not net present value, ignores financing, price variation, upkeep and possible disruptive works, and may not occur.