Heat Pump vs Gas Furnace: The Real Operating-Cost Math
Updated August 2026
In plain numbers: One ratio settles most of this argument. At typical efficiencies, a heat pump wins on running cost when your electricity price in cents per kWh is below about 3.5 times your gas price in dollars per therm. Run national averages through that and you land near a tie, which is why the honest answer is regional rather than national. Heat pumps win comfortably across the mild South and the cheap-power Northwest. Gas holds its ground in cold states where therms are cheap and kilowatt-hours aren't. Put your own two numbers into the calculator and the tie breaks one way or the other in about ten seconds.
The crossover formula
A modern heat pump moves roughly 3 units of heat for every unit of electricity it draws, which is a seasonal COP near 3. A good gas furnace turns about 95% of its fuel into heat in your ducts. Push both through the energy math and the break-even comes out at: heat pump wins if ¢/kWh is under 3.5 × $/therm.
Put numbers on it. At 17¢ electricity, gas has to cost more than roughly $1.60 a therm before the heat pump pulls ahead on running cost alone. Pay 13¢ for power, like much of the Northwest does, and the threshold drops to about $1.22, which almost nobody's gas bill beats. Pay 28¢, as parts of New England do, and gas would need to hit $2.40 before the heat pump catches up.
That one line explains the whole regional map. Cheap hydro power in the Pacific Northwest and mild winters in the South keep heat pumps in front. Pockets of the Midwest and Northeast with cheap gas and expensive electricity still pencil out for the furnace. There is no national answer here, only the answer sitting on your own utility bill.
The cold-climate caveat, updated
The old line about heat pumps dying below freezing is a decade out of date. Cold-climate models hold useful efficiency down to -5°F and keep producing heat below that, and Maine of all places has turned into an adoption leader. What's genuinely true is that COP slides as the thermometer does. A unit averaging 3.0 across a Carolina winter might average 2.2 across a Minnesota one, and your cost math has to use that seasonal number, not the figure printed on the spec sheet at 47°F.
Then there's backup heat, which is where the savings actually go to die. Resistance strips run at COP 1, so every hour they cover for the compressor costs about three times what the heat pump would have charged you. An undersized system leaning on strips through January can turn a projected 30% saving into a bill that's higher than the furnace it replaced. Sizing and install quality matter more on a heat pump than on any furnace ever made. Pick the contractor before you pick the brand.
Dual fuel: the unsexy right answer for many
Dual fuel means running a heat pump for the 80 to 90% of the season that's merely chilly, then handing off to the gas furnace below a set switchover temperature. You get the cheap shoulder-season heat and keep the furnace's brute-force economy for the cold snaps. If you already own a working furnace, bolting on a heat pump and demoting the furnace to backup is usually the highest-return configuration available to you.
Set that switchover point from prices, not folklore. The same 3.5× ratio tells you the outdoor temperature at which falling COP hands the advantage back to gas. Installers tend to default it high, somewhere around 35°F, because nobody gets a callback for a house that's too warm. Spend half an hour with your actual rates and you'll usually move it down into the 20s and keep real money.
FAQ
Is a heat pump cheaper to run than a gas furnace?+
Yes, when your electricity price in ¢/kWh is under about 3.5 times your gas price in $/therm. National averages land close to a tie, so it splits by region: cheap-electricity and mild-winter states favor the heat pump, cheap-gas cold states favor the furnace.
Do heat pumps work below freezing?+
Cold-climate models heat effectively down to -5°F and beyond, just at reduced efficiency. The cost risk isn't the cold itself, it's resistance backup strips taking over in an undersized system and charging you triple.
What is dual-fuel heating?+
A heat pump paired with a gas furnace. The heat pump covers mild weather cheaply and the furnace takes over below a switchover temperature you set. In cold climates with existing gas service, it's often the lowest total cost setup.
Does a heat pump make sense if my furnace still works?+
Often, yes, because you don't have to remove it. Adding a heat pump and keeping the furnace as backup gives you dual fuel without paying for a replacement furnace, and you gain air conditioning from the same box.