Calculator
Boiler Fuel Consumption Calculator
Calculate how much fuel your boiler consumes based on steam demand, operating pressure, feedwater temperature, and efficiency. Estimate daily and annual fuel costs for natural gas, oil, or coal.
Interactive toolUpdated July 2026
Inputs
Typical: 80–92%
Results
Fuel Consumption
198.8 Nm³/hr
Energy Required
7,555.2 kW
Heat input from fuel
Estimated Daily Cost
$2,385.8
Gas: $0.50/Nm³ · Oil: $1.20/kg
Estimated Annual Cost
$787,330.3
Based on 330 operating days
How It's Calculated
The fuel consumption is calculated by determining the energy needed to produce the required steam, then dividing by the fuel's calorific value and boiler efficiency:
Energy Output = Steam Flow × (h_steam − h_feedwater)
Energy Input = Energy Output / Efficiency
Fuel Consumption = Energy Input / Calorific Value
Energy Input = Energy Output / Efficiency
Fuel Consumption = Energy Input / Calorific Value
Calorific values used: Natural gas: 38 MJ/Nm³. Fuel oil: 42 MJ/kg. Coal: 24 MJ/kg.
Ways to Reduce Fuel Consumption
- Improve boiler efficiency — every 1% efficiency improvement saves 1% of fuel. Clean tubes, tune the burner, reduce excess air.
- Increase feedwater temperature — every 6°C increase in feedwater temperature saves approximately 1% fuel. Use an economiser or deaerator.
- Reduce blowdown — every 10% reduction in blowdown saves about 0.5% fuel. Install automatic TDS control.
- Recover flash steam — condensate flash steam recovery can save 5–15% of fuel.
- Insulate all hot surfaces — uninsulated piping and fittings radiate heat continuously.
- Reduce steam leaks — a 3mm hole on a 10 bar system wastes 25 kg/hr of steam, equivalent to thousands of dollars per year.
- Operate at the correct pressure — don't generate higher pressure than needed. Each bar of unnecessary pressure costs fuel.