Combine insulation layers into a total R-value and heat loss.
Insulation layers add to a total R-value, whose inverse is the U-factor. Multiplying the U-factor by surface area and temperature difference estimates the heat loss. Resistance to heat flow is what R-value measures, so stacking correct values shows whether an assembly meets a target.
Insulation R-Value
U-factor = 1 / total R-value; heat loss = area x U x temperature difference
U-factor = 1 / total R-value; heat loss = area x U x temperature difference Insulation layers add to a total R-value, whose inverse is the U-factor. Multiplying the U-factor by surface area and temperature difference estimates the heat loss.
Resistance to heat flow is what R-value measures, so stacking correct values shows whether an assembly meets a target.
This calculator takes 5 inputs: Layer 1 R-value, Layer 2 R-value, Layer 3 R-value, Surface area, Temperature difference. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.