Heat Loss Calculator
Quantifying What Never Reaches the Process
Every combustion system loses some fraction of its fuel energy to flue gas, radiation, and surface losses. This calculator finds that loss directly from a known heat input and efficiency figure.
The Formula
Heat Loss = Heat Input × (1 − Efficiency% / 100)
Worked Example
A boiler with 300 kW heat input at 82% efficiency:
Heat Loss = 300 × (1 − 0.82) = 54 kW (18%)
How to Use This Calculator
- Enter the Heat Input in kW.
- Enter the equipment's Efficiency percentage.
- Select Calculate to get the heat lost, in kW and percentage.
Related Calculations
Break this down by flue gas specifically in the Stack Loss Calculator, or check the efficiency this is based on in the Boiler Efficiency Calculator.