Steam Boiler Efficiency Calculator

Steam Boiler Efficiency Calculator: Measure Real-World Fuel-to-Steam Conversion

Overall boiler efficiency tells you what fraction of the fuel's energy actually ends up in the steam you use, versus what's lost to flue gases, radiation, and blowdown. This calculator compares the useful steam energy output against the fuel energy input to give you a direct efficiency figure.

The Formula

Efficiency% = (Steam Flow × Enthalpy Gain) / (Fuel Flow × Heating Value × 1000) × 100

Worked Example

A boiler produces 1,000 kg/hr of steam with a 2,200 kJ/kg enthalpy gain, burning 61.6 kg/hr of fuel with a heating value of 42 MJ/kg.

Efficiency = (1,000 × 2,200) / (61.6 × 42 × 1000) × 100 = 85.03%

How to Use This Calculator

  1. Enter the measured steam flow rate in kg/hr.
  2. Enter the enthalpy gain in kJ/kg.
  3. Enter the measured fuel flow rate in kg/hr.
  4. Enter the fuel heating value in MJ/kg.
  5. Click Calculate to get the overall boiler efficiency percentage.

Related Calculations

Compare against the Boiler Efficiency Calculator and Boiler Fuel Requirement Calculator for a complete efficiency audit.