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Heat pump vs gas furnace: which to spec for the job
A heat pump moves heat and does both heating and cooling; a furnace burns fuel for hot air and deep-cold output. Climate and fuel cost decide it.
Short answer
Pick a heat pump when the building needs both heating and cooling and the climate is mild to moderate, because one refrigerant system does both jobs and moves more heat than the electricity it draws (a COP of 3 delivers 3 units of heat per unit of power). Pick a gas furnace when the climate runs deep cold, gas is cheap, or the customer wants furnace-hot supply air and brute output that does not fall off as it gets colder. The single biggest deciding factor is climate severity weighed against local electricity-versus-gas rates: a heat pump loses capacity as outdoor air drops and leans on backup heat below its balance point, while a furnace holds full output at any outdoor temperature.
Heat pump vs Gas furnace: side by side
| Factor | Heat pump | Gas furnace |
|---|---|---|
| How it works | Moves existing heat with a refrigerant cycle; reversing valve flips between heating and cooling | Burns natural gas or propane in a sealed heat exchanger; blower moves air over it |
| Efficiency ceiling | COP above 1; can move ~3 units of heat per unit of electricity | AFUE ~80% non-condensing, 90%+ condensing; tops out near 1:1 fuel to heat |
| Heating and cooling | Both in one system, no separate AC needed | Heating only; pair with a separate cooling system |
| Supply air temp | Typically 90 to 110°F; feels lukewarm, runs longer | Roughly 120 to 140°F or hotter; feels hot at the register |
| Cold-weather output | Capacity falls as it gets colder; needs backup below the balance point (often ~25 to 35°F) | Full output at any outdoor temperature; no backup needed |
| Backup / supplemental | Electric strip heat or a dual-fuel furnace below balance point and during defrost | None required; it is the heat source |
| Primary safety concern | Correct charge and normal defrost; no combustion | Combustion safety, CO, cracked heat exchanger (life-safety, red-tag) |
| Code / standard | DOE minimums, AHRI ratings (SEER2/HSPF2), EPA 608, manufacturer data | Fuel-gas code (NFPA 54 / IFGC) plus manufacturer instructions |
| Best use | Mild to moderate climates, cooling needed, electrification | Cold climates, cheap gas, demand for hot supply air |
Which should you pick?
Choose Heat pump when
- The building needs cooling too and you want one system to cover both loads
- Climate is mild to moderate, or cold-climate inverter/vapor-injection equipment keeps the balance point low
- Electrifying heat is the goal, or electricity is cheap relative to gas
- No gas service, or you want to avoid combustion, flue, and CO exposure entirely
Choose Gas furnace when
- Climate runs deep cold and you need full output that does not fall with outdoor temperature
- Gas is cheap relative to electricity in the local market
- The customer wants furnace-hot supply air, not the gentle 90 to 110°F a heat pump delivers
- Retrofit where adding backup strip heat or right-sizing a heat pump is impractical
Bottom line
It depends on climate severity and the local electricity-versus-gas cost. In mild to moderate regions a heat pump usually wins because it heats and cools in one system and moves several units of heat per unit of electricity; in deep cold or where gas is cheap, a furnace delivers brute output and hot air without a backup-heat penalty. Dual-fuel splits the difference: run the heat pump in shoulder weather and hand off to the furnace below an economic switchover set from the equipment and the utility rates. Whatever you spec, the efficiency on the plate only shows up if the install and setup are right: verify charge and airflow on the heat pump, and set manifold pressure, temperature rise, and a clean combustion check on the furnace.
FAQ
Is a heat pump cheaper to run than a gas furnace?
Often, in mild to moderate weather, because a heat pump moves heat instead of making it and can deliver about three units of heat per unit of electricity, where a furnace tops out near one unit of heat per unit of fuel. The advantage shrinks as it gets colder, since the heat pump loses capacity and leans on resistance strip heat at a COP of 1. Whether it actually costs less depends on local electricity-versus-gas rates and the balance point.
Why does heat pump air feel cooler than furnace air?
That is normal, not a fault. A heat pump's indoor coil typically delivers supply air around 90 to 110°F, while a gas furnace blows air off the heat exchanger around 120 to 140°F or hotter. The heat pump moves a large amount of heat at a modest temperature, so it runs higher airflow at a lower supply temperature and heats the house over longer cycles.
Should I get a heat pump or a furnace for a cold climate?
In deep cold, a gas furnace holds full output at any outdoor temperature, while a standard heat pump's capacity falls and it needs backup heat below its balance point (often around 25 to 35°F). Cold-climate inverter and vapor-injection heat pumps hold useful capacity well below freezing and push that balance point lower. A dual-fuel system pairs the two, running the heat pump in shoulder weather and switching to the furnace in deep cold.