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Heat Pump vs Furnace Running Cost
A heat pump moves heat rather than making it, which is why it can beat a furnace. Here is how the running cost comparison actually works in cold weather.
Comparing a heat pump against a furnace is not a comparison of two efficiencies. They do different things — one moves heat that already exists, the other creates it by burning fuel — and that difference is why the answer depends so heavily on your climate and your local fuel prices.
Getting the comparison right requires converting both to cost per unit of delivered heat, which is the step most discussions skip.
Moving heat beats making it
A furnace burning gas can convert most of the fuel's energy into heat. It cannot exceed 100%, because you cannot get more energy out than you put in.
A heat pump is not converting energy into heat; it is moving heat from outside to inside using electricity. Because it is a transport mechanism rather than a conversion, it can deliver several times more heat energy than the electrical energy it consumes.
That is why the comparison is not about efficiency ratings in the ordinary sense. A heat pump delivering three units of heat per unit of electricity is doing something a furnace cannot do at any efficiency.
The catch is that the performance falls as it gets colder. There is less heat outside to move, and the pump works harder to move it. Cold-climate models have improved this substantially — many now maintain useful output well below freezing — but the direction of the effect is unavoidable.
Do the comparison in cost per delivered unit
The comparison that works:
For the furnace, take the fuel price per unit, divide by the system's efficiency, and convert to a common heat unit.
For the heat pump, take your electricity rate, divide by the seasonal performance factor, and convert to the same unit.
Whichever is lower wins on running cost. The heat pump vs furnace calculator does the conversion, and the energy cost calculator covers finding your real rates — including delivery charges, which are frequently a large share of an electricity bill and are routinely omitted from these comparisons.
Three patterns emerge consistently.
Against electric resistance heat, it wins overwhelmingly everywhere. This is the easiest case and the largest saving available.
Against propane or heating oil, it usually wins, because those fuels are expensive per unit of heat.
Against cheap natural gas, it is genuinely close and depends on your local ratio of electricity to gas prices. In regions with cheap gas and expensive electricity, the gas furnace can remain cheaper to run.
The heat pump backup problem
This is where real bills diverge from projections.
Most installations include electric resistance backup for very cold periods or rapid recovery. Resistance heat is the most expensive common heating method there is.
If the system calls for backup frequently, the average cost rises sharply toward resistance rates and away from the unit's efficient performance. A household seeing unexpectedly high bills usually has a backup that is engaging more than it should.
Common causes are worth knowing because most are fixable: an undersized heat pump, a thermostat that triggers backup on any deviation, a deep setback prompting aggressive recovery, or a control strategy set to a changeover temperature higher than necessary.
A dual fuel arrangement — heat pump paired with a gas furnace, switching at whatever outdoor temperature makes the gas cheaper — sidesteps this entirely and is often the lowest-cost configuration where gas is available.
What the running cost comparison leaves out
Cooling. A heat pump is an air conditioner running in reverse. Replacing a furnace and a separate air conditioner with one system means one installation and one piece of equipment to maintain, which changes the capital comparison substantially. The air conditioner sizing guide covers why sizing matters for the cooling side.
Installation cost and complexity. Ductwork condition matters a great deal — leaky ducts in unconditioned space undermine any system, which the insulation guide covers. Ductless systems avoid it and cost differently.
Electrical capacity. A unit with resistance backup may require a service upgrade, which is a significant and frequently unanticipated cost.
Incentives. Rebates and tax credits for heat pumps have been substantial and change frequently. Verify current availability with your utility and the Department of Energy rather than a figure from a sales document.
Equipment life and maintenance. It runs year-round rather than seasonally.
Fuel price volatility. You are choosing exposure as well as a cost. Gas and electricity prices move differently, and a dual fuel system hedges that.
Reduce the load before sizing the system
The order matters and it saves money twice.
A house that loses less heat needs a smaller system, and a smaller system costs less to buy and less to run. Doing the envelope work first means the equipment can be specified against the improved load rather than the current one.
In order of return: air sealing and insulation, duct sealing where ducts run through unconditioned space, then setback scheduling, which costs nothing at all.
Then insist on a proper load calculation rather than a rule of thumb based on floor area. Oversizing is the most common specification error: an oversized system short-cycles, controls humidity poorly, wears faster, and costs more to buy. The energy audit guide covers establishing the actual load, and it is the input that makes every other number in the comparison meaningful.