Verify the inputs
Measure or document each input. If a value is only an estimate, record its source and test a conservative alternative.
Insulation/ CALCULATOR
Insulation heat and energy savings
Screen the annual transmission-heat, purchased-energy and cost reduction from improving one building element.
FROM ESTIMATE TO ACTION
Use the result, not just the number.
Keep the calculation traceable
Save the input link or copied result together with the date, units and assumptions. A number without its inputs cannot be checked later.
Confirm the decision
Compare the estimate with the related guide, current product data and requirements that apply at your location before buying or building.
Inputs to verify
- Insulated element area (m²)
- Use the net wall, roof or floor area represented by both U-values.
- U-value before improvement (W/m²·K)
- Include the whole existing assembly, not only the insulation layer.
- U-value after improvement (W/m²·K)
- Use the proposed whole-assembly value including thermal bridges where available.
- Annual heating degree-days (K·day/year)
- Use a local long-term value with the base temperature stated by its source.
- Delivered heat per purchased energy (kWh/kWh)
- Use seasonal efficiency for a boiler or seasonal performance factor for a heat pump.
- Purchased-energy price (currency units/kWh)
- Enter a comparable all-in marginal price in one currency.