Use our simple but effective calculator to estimate the U-value of a building’s surface, such as a wall or roof, in W/m²K. Helps to estimate potential insulation improvements, or meet building regulations. No signup, no subscription.

Notes

• Estimate includes R-values for Outdoor Resistance and Indoor Resistance. I.e. the layer of air next to the inner and outer surfaces
• Estimate does not include mortar, air gap, or wall tie adjustments. These usually come to <0.01W/m²K on top of final U-value, but you’ll need to check if you need a precise figure.
• Estimate is just an estimate. Make sure to double-check using your own calculations if critical for hitting building regs.