If you're replacing a heating system or building a new home, the heat pump vs furnace decision is one of the most important energy choices you'll make. The right answer depends on your climate, existing setup, energy costs, and long-term goals. Here's what you need to know.
How Each System Works
A furnace generates heat by burning fuel — typically natural gas, propane, or heating oil. It's a straightforward combustion process that produces warm air distributed through ducts. Furnaces are effective in very cold climates and the infrastructure is well established across the US.
A heat pump doesn't generate heat — it moves it. In winter, it extracts heat from outdoor air (even cold air contains heat energy) and moves it inside. In summer, it reverses direction and works as an air conditioner. Modern cold-climate heat pumps work efficiently down to -15°F (-26°C), which surprises many homeowners.
Efficiency: Heat Pumps Win by a Wide Margin
This is the most important difference. Furnaces convert fuel to heat at efficiencies of 80–98%. A high-efficiency gas furnace might produce 98 BTUs of heat for every 100 BTUs of gas burned.
Heat pumps operate at 200–400% efficiency — meaning they deliver 2–4 units of heat energy for every unit of electricity consumed. This is possible because they're moving heat, not creating it. In mild to moderate climates, a heat pump can cost 50–60% less to operate than an electric resistance furnace and often beats gas furnaces on operating cost when electricity rates are reasonable.
Upfront Cost Comparison
Heat pumps cost more upfront. A gas furnace with central air conditioning (two separate systems) typically runs $5,000–$10,000 installed. A heat pump system that handles both heating and cooling runs $8,000–$15,000 installed — but you're replacing two systems with one.
Federal tax credits under the Inflation Reduction Act provide up to 30% back on heat pump installations (up to $2,000), significantly narrowing the gap. Many states offer additional rebates.
Climate Considerations
Heat pumps perform best in mild to moderate climates (USDA zones 4–8). In very cold climates — think Minnesota, Vermont, or Wisconsin — older heat pump technology struggled. Modern cold-climate heat pumps have largely solved this problem, but in extreme cold snaps, a backup heat source (electric resistance strips or a gas furnace in a "dual fuel" setup) is often recommended.
In hot climates like the Southeast, heat pumps are almost always the better choice. They handle both heating and cooling efficiently, and winters are mild enough that heating demand is low.
Environmental Impact
If your electricity grid is relatively clean (renewables, nuclear, or natural gas generation), heat pumps produce significantly fewer carbon emissions than gas furnaces — typically 50–70% less. As grids continue to decarbonize, this advantage grows over time. A heat pump installed today will get cleaner every year as your utility adds more renewables to the grid.
Gas furnaces, regardless of efficiency improvements, will always burn fossil fuels and produce carbon emissions at the point of use.
Which Should You Choose?
Choose a heat pump if: You're in a mild to moderate climate, your electricity rates aren't extremely high, you want to reduce your carbon footprint, or you're replacing both a furnace and AC at the same time.
Choose a furnace if: You're in a very cold climate and aren't ready for a cold-climate heat pump, you have very cheap natural gas, or you have an existing system that doesn't need full replacement yet.
For most homeowners replacing aging systems, a heat pump is the better long-term investment — lower operating costs, one system instead of two, and a shrinking carbon footprint as the grid cleans up.
Related Tools
Use our Heating vs Cooling Cost Calculator to estimate your current heating costs, or our Green Home Upgrade ROI Calculator to model the payback period on a heat pump installation.