Steady Wall Heat Transfer Calculator
Estimate steady heat flow through a surface from its U-value and temperature difference.
Your result
EVERYDAYEnter your values and select calculate.
On this page How it works & practical examples
How to use the Steady Wall Heat Transfer Calculator
Use the overall assembly U-value and one surface area. Temperature differences in Celsius have the same numerical magnitude as kelvin differences.
The calculation
Worked example
20 m², U = 0.3 W/(m²·K) and a 20 °C difference give 120 W and 2.88 kWh over 24 hours.
Assumptions and limits
Steady one-dimensional estimate; thermal bridges, air leakage, solar radiation and thermal storage are excluded. The sign of the temperature difference determines heat direction.
Common questions
Which inputs should I use?
Use the overall assembly U-value and one surface area. Temperature differences in Celsius have the same numerical magnitude as kelvin differences.
What does the result exclude?
Steady one-dimensional estimate; thermal bridges, air leakage, solar radiation and thermal storage are excluded. The sign of the temperature difference determines heat direction.