Heat Pump vs. Fossil Fuel Cost Comparison Calculator
Compare the annual operating costs of a heat pump against natural gas, oil, or propane heating systems to estimate your potential savings.
Typical home: 40–120 MMBtu/year. Check your utility bills or use 60 as a starting point.
Modern air-source heat pumps: 2.0–3.5; ground-source: 3.0–5.0. Average: 2.5.
U.S. average ~$0.13/kWh. Check your electric bill for your actual rate.
U.S. average ~$1.20/therm for natural gas.
Standard furnace: 80%; high-efficiency: 90–98%. Check your equipment label.
Formulas Used
Heat Pump Annual Cost:
HP Cost = (Heating Load [MMBtu] ÷ COP) × 293.071 [kWh/MMBtu] × Electricity Rate [$/kWh]
Fossil Fuel Annual Cost:
Fossil Cost = (Heating Load [MMBtu] ÷ AFUE) ÷ Fuel Energy Content [MMBtu/unit] × Fuel Price [$/unit]
Annual Savings:
Savings = Fossil Cost − HP Cost
Fuel Energy Content: Natural Gas = 0.1 MMBtu/therm | Heating Oil = 0.138 MMBtu/gal | Propane = 0.0915 MMBtu/gal
Unit Conversion: 1 MMBtu = 293.071 kWh
Assumptions & References
- Heat pump COP is assumed constant (seasonal average). Real-world COP varies with outdoor temperature.
- AFUE (Annual Fuel Utilization Efficiency) represents the fraction of fuel energy converted to useful heat per ANSI/ASHRAE Standard 103.
- Fuel energy content values sourced from the U.S. Energy Information Administration (EIA).
- Electricity conversion: 1 MMBtu = 293.071 kWh (exact thermodynamic conversion).
- U.S. average electricity rate ~$0.13/kWh (EIA, 2024); natural gas ~$1.20/therm; heating oil ~$3.50/gal; propane ~$2.50/gal.
- Installation costs, maintenance, and carbon emissions are not included in this operating-cost comparison.
- Cooling costs (heat pumps provide both heating and cooling) are not included; actual heat pump savings may be higher.
- Results are estimates. Consult an HVAC professional for a site-specific analysis.