Heat Pump vs Propane, Oil, or Resistance Heat

A fuel comparison is only meaningful when each option is asked to deliver the same service. A gallon of propane, a litre of heating oil, a kilowatt-hour of electricity, and a unit of gas are different billed quantities. Compare the cost of heat that reaches the rooms, not the price printed beside one fuel on its own. Then check the equipment and project costs that would change if the home switches.

Put every fuel on a useful-heat basis

First estimate annual space-heating demand, preferably from bills, a heat-loss assessment, or another documented method. Separate domestic hot water and cooking when they use the same fuel. Next translate the invoice quantity into energy using an appropriate heat-content factor for that fuel and local billing unit. Suppliers may bill propane by gallon or litre, oil by litre or gallon, and electricity by kWh; do not silently mix U.S. gallons, Imperial gallons, litres, therms, or cubic metres. For a real project, check the conversion basis with the supplier or a trusted energy agency.

Then account for equipment performance. A furnace or boiler uses more fuel energy than the heat it delivers; represent that with a seasonal efficiency, not just a laboratory rating. Electric resistance heat produces about one unit of heat at the point of use per unit of electricity, although distribution losses and room-level controls still matter. A heat pump’s seasonal performance varies with outdoor temperature, the system design, controls, defrosting, and any resistance or fossil-fuel backup. A product rating helps compare equipment under defined tests; it is not a prediction of this home’s annual result.

The conceptual comparison is:

annual cost of useful heat = delivered heat ÷ seasonal system performance × local billed energy price

For combustion systems, express seasonal performance as the fraction of fuel energy becoming useful indoor heat. For heat pumps, use a seasonal heat-to-electricity ratio that matches the operating boundary. If two systems cover different rooms or hot-water uses, split the services and compare only like with like.

Use delivered prices and include the right charges

Use the household’s delivered invoice cost, not a wholesale quote or a national average. For propane or oil, the invoice may include delivery, minimum-drop rules, tank rental, service, taxes, or a price contract. A fixed delivery fee may matter more in a low-use year than in a cold one. Record actual quantity and amount over a full heating season where possible. If the price is variable, test a reasonable range rather than assuming today’s price lasts for the equipment’s life.

Electricity and gas bills have their own unit rates, delivery charges, standing charges, taxes, and credits. Some apply whether the heating equipment runs or not. Count a fixed charge as an avoided cost only when switching makes it go away. A house that keeps gas for a water heater may keep much of its gas connection charge. A heat pump also adds electric use at the times it runs; with time-of-use or peak rates, annual average price may misstate that use. See the Great Britain tariff guide for a worked illustration of comparing unit rates and standing charges.

Add backup, equipment, and the project boundary

If the heat pump uses a furnace, boiler, or resistance elements during colder hours, estimate how much heat each source supplies. The balance temperature depends on equipment capacity, building load, weather, rates, and control settings. It should come from a system-specific design and cost calculation, not a rule copied from another climate. If the existing oil or propane equipment is retained for backup, include its service and standby requirements. If it is removed, include removal, tank handling, electrical upgrades, emitters, duct changes, or other enabling work that is actually in the quote.

Keep annual running cost separate from installed cost. A low-cost operating option may require more capital work, while an existing appliance that is near replacement should not be treated as a free alternative. For each option, list the equipment included, expected lifetime assumptions, maintenance, incentives only when eligibility is confirmed, and financing separately. Avoid adding a full fuel bill to one side while counting only the competitor’s marginal energy charge on the other.

Check whether the answer travels to your home

Fuel-price summaries can orient a reader but do not establish a household ranking. U.S. Energy Information Administration fuel prices are averages for their stated market and unit; they are not a delivered quote for every household. Likewise, a modeled regional comparison depends on its home, climate, utility rate, and assumed equipment. Use such results to identify questions, then replace their inputs with this home’s bills and a local design estimate.

Make low, central, and high cases for heat demand, fuel price, seasonal performance, and backup share. If the ranking changes across plausible cases, the honest answer is that the result is sensitive. Ask the contractor to show annual energy use, expected backup, and the conditions behind the estimate. Check that the proposed system provides the same comfort, rooms, hot water, and cooling as the existing setup.

The useful next step is to gather one year of fuel and electricity invoices, document units and non-energy charges, and request a comparable scope from each installer. This method does not promise that a heat pump will lower a particular bill; it shows which household facts determine the answer. For a capital premium and simple-payback calculation, continue to the payback assumptions guide.