HTHOMETALLYTHE PRACTICAL HOME GUIDE

Insulation/ CALCULATOR

Extra insulation thickness

Estimate an ideal continuous layer needed to reach a target U-value.

Whole existing assembly value.
Choose a target appropriate to your assembly and climate.
Use the declared product conductivity.
Ideal additional thickness

100.0 mm

Ideal one-dimensional continuous insulation; ignores fixings, gaps and new bridges. Does not check condensation, fire performance or product suitability. Zero means no extra layer is required by this simplified thermal calculation.

FROM ESTIMATE TO ACTION

Use the result, not just the number.

01

Verify the inputs

Measure or document each input. If a value is only an estimate, record its source and test a conservative alternative.

02

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.

03

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

Existing U-value (W/m²K)
Whole existing assembly value.
Target U-value (W/m²K)
Choose a target appropriate to your assembly and climate.
Insulation conductivity (W/mK)
Use the declared product conductivity.

Continue your calculation

Insulation

Assembly heat loss

Compare heat flow through a wall, roof or window area.