The following list of heating fuel types displays estimated cost in dollars per million British Thermal Units (BTU)s of heat produced. This allows you to compare one fuel type to another. Average equipment efficiencies and fuel costs are assumed. To calculate a more exact cost for your individual situation, please call toll free (208) 743-1501 and ask for the Member Services Department.
| Heating Source | Cost per Unit | Efficiency / COP | Cost / Million BTUs |
|---|---|---|---|
| Ground Source Heat Pump | $0.0903 / kWh | COP 3.5 | $7.56 |
| Air Source Heat Pump | $0.0903 / kWh | COP 2.5 | $10.59 |
| Natural Gas | $0.70 / therm | 70% | $10.00 |
| Fuel Oil | $5.10 / gallon | 80% | $46.02 |
| Propane Furnace | $2.15 / gallon | 80% | $29.43 |
| Electric Resistance | $0.0903 / kWh | 100% | $26.49 |
Updated Oct, 2026