Heating Oil Consumption Calculator
Sizing Heating Oil Supply and Tank Draw Rate
Heating oil consumption depends not just on heat demand but on boiler efficiency, since a less efficient boiler needs more fuel input to deliver the same useful heat output.
The Formula
Oil Consumption = (Heat Input(kW) × 3.6) / (Heating Value(MJ/L) × Efficiency%)
Heating oil has a heating value around 36.7 MJ/L, used as the default if not specified; boiler efficiency defaults to 85%.
Worked Example
A boiler delivering 25 kW of heat at 85% efficiency:
Consumption = (25 × 3.6) / (36.7 × 0.85) = 2.89 L/hr
How to Use This Calculator
- Enter the required Heat Input in kW.
- Enter the Boiler Efficiency (defaults to 85%).
- Optionally enter the oil's Heating Value (defaults to 36.7 MJ/L).
- Select Calculate to get oil consumption in L/hr.
Related Calculations
Check the boiler efficiency this depends on in the Boiler Efficiency Calculator, or size the burner in the Burner Capacity Calculator.