We use hourly temperature data from the nearest weather station to your location, covering the past year. Combined with your home's size and insulation level, we calculate how much heat your home loses at each temperature. Then we compare what each heating system would cost to replace that heat — using real efficiency ratings and local fuel prices.
A dual-fuel system pairs a heat pump with a fossil fuel backup (gas furnace, oil boiler, or propane furnace). The heat pump runs when it's efficient, and the backup kicks in during extreme cold when the heat pump's efficiency drops. This is the most popular setup in cold climates — you get the efficiency of a heat pump most of the year with the reliability of your existing furnace as backup.
Heat pumps move heat from outside air into your home. When it's warmer outside, there's more heat energy available, so the heat pump works more efficiently (higher COP). As temperatures drop, the COP decreases. Modern cold-climate heat pumps (HSPF2 10+) maintain good efficiency well below 0°F, but budget models lose performance faster.
The equipment costs shown are rough national averages for fully installed systems. Actual costs vary widely based on your location, home layout, existing ductwork, and installer. Get 2-3 local quotes for accurate pricing. The 10-year total cost helps you see the long-term picture even if upfront costs differ from our estimates.
Yes. Cooling loads are calculated from your home's heat gain — including conduction through the building envelope plus internal heat from occupants, appliances, and sunlight. Heat pumps provide both heating and cooling natively. For fossil fuel systems (gas furnace, oil boiler, propane), we add the cost of running a standard central AC (SEER2 15). For electric baseboard homes, we assume window units (SEER2 12). This gives you a true apples-to-apples annual HVAC comparison.
The federal 25C tax credit ($2,000 for heat pumps) expired at the end of 2025. However, many state and utility programs still offer significant rebates — some over $10,000. Check dsireusa.org or your local utility's website for current incentives in your area. Rebates are not factored into the costs shown above.
We use state-level residential energy prices from the U.S. Energy Information Administration (EIA), updated weekly. You can override any fuel price using the "Customize fuel prices" section to match your actual utility rates for the most accurate comparison.