How Wall Heat Loss Calculator Works
Estimate steady-state heat loss through a wall from area, thermal resistance and indoor/outdoor temperature difference. The calculation runs locally in your browser and does not require an account.
How to use it
- Enter values using the units shown.
- Check your source measurements and assumptions.
- Calculate and compare scenarios before making a decision.
Limitations
Wall Heat Loss Calculator is an estimation aid. For a critical result, compare the inputs and output with the applicable standard, manufacturer data, project specification, site condition, or qualified professional review.
What the heat-loss estimate means
The calculated heat loss represents steady-state conduction through the wall using a simplified thermal resistance. A larger wall area or temperature difference increases heat loss, while better insulation increases resistance and reduces it. The result is useful for comparing insulation scenarios and estimating a first-pass heating requirement.
A building envelope calculation normally includes windows, doors, roofs, floors, thermal bridges and air leakage in addition to wall conduction. Solar gains, internal gains and ventilation can also change the actual heating or cooling load. Treat this result as one component of a complete building-load calculation rather than as a final equipment-sizing value.