Boiler Efficiency Calculator

Calculate boiler thermal efficiency from fuel consumption and steam output. Uses the direct (input/output) method: η = (steam mass × Δh) / (fuel mass × LHV). Steam enthalpies come from IAPWS-IF97; fuel lower heating values are pre-loaded for natural gas, fuel oil (No. 2 / No. 6), coal (bituminous, anthracite, lignite), and biomass (wood pellets, wood chips).

Inputs: fuel type and consumption rate, feedwater temperature, steam pressure, steam temperature (or saturated), and steam mass flow. Returns efficiency, fuel-to-steam ratio, and energy balance.

Related steam calculators: steam tables, flash steam, condensate load.