Heat Transfer Calculator
Conduction heat loss through a wall.
Enter your values
ⓘ Live results
Results
- Heat loss
- 1036.8 W
- Daily energy
- 24.88 kWh
- U-value
- 2.4 W/m²K
- Annual cost at $0.25/kWh
- $1,119.74
Quick answer
Conductive heat loss rises with area and temperature difference and falls with thickness.
Q = k × A × ΔT ÷ thickness
How to use the Heat Transfer Calculator
- 1Enter wall area and thickness.
- 2Enter the material's thermal conductivity.
- 3Enter the inside-outside temperature difference.
Worked example
Using the values the calculator loads with:
Inputs
- Area24 m²
- Thickness0.25 m
- Conductivity0.6 W/mK
- Temperature difference18 °C
Results
- Heat loss1036.8 W
- Daily energy24.88 kWh
- U-value2.4 W/m²K
- Annual cost at $0.25/kWh$1,119.74
Frequently asked questions
What is a good U-value?
Below 0.3 W/m²K for modern insulated walls.
Does this include air films?
No — real U-values add internal and external surface resistances.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.