Formula & worked example
Useful heat cost=fuel energy price/η; annual fuel input=useful heat demand/η.
At 85% versus 92% efficiency, equal nominal energy prices do not produce equal useful-heat cost.
Plant engineering calculator · Updated Sep 17, 2026
Boiler Fuel Comparison Calculator — Useful Heat Cost & Annual Savings
Compare two boiler fuels on a common useful-heat basis using fuel energy price and boiler efficiency. Returns useful heat cost, annual fuel input, annual spend, savings and break-even fuel price.
Inputs
Live result
Fuel A useful-heat cost 0.05882353 /kWh useful
Fuel B useful-heat cost 0.06521739 /kWh useful
Fuel A input 11,764.71 MWh/yr
Fuel B input 10,869.57 MWh/yr
Fuel A annual spend 588,235.3
Fuel B annual spend 652,173.9
Annual saving using lower-cost option 63,938.62
Fuel B break-even price 0.05411765 /kWh
Assumptions & limits
- Fuel prices must be normalized to the same energy basis such as kWh LHV.
- Taxes, demand charges, maintenance and emissions costs are excluded unless embedded in the entered energy price.
Frequently asked questions
What does this Boiler Fuel Comparison Calculator calculate?
Compare two boiler fuels on a common useful-heat basis using fuel energy price and boiler efficiency. Returns useful heat cost, annual fuel input, annual spend, savings and break-even fuel price.
Can I use the result for final equipment selection?
Use it for screening, benchmarking and option comparison. Final selection should use measured conditions, manufacturer performance data and applicable engineering standards.
Why are assumptions shown beside the calculation?
Plant calculations change materially with pressure basis, reference conditions, efficiencies and operating profile. Explicit assumptions make the result auditable instead of hiding those choices.