This is the most common question we're asked at replacement time, and most of the advice available online is a decade out of date. Cold-climate heat pump technology has changed substantially since 2015 — but that doesn't make it automatically correct for your house.
Here's how the decision actually works.
The fundamental difference
A furnace creates heat by burning fuel — natural gas, propane or oil. It's a combustion appliance, and its efficiency is capped at 100% of the energy in the fuel. Good modern furnaces reach 95–98%.
A heat pump doesn't create heat at all. It moves existing heat from outdoor air into your home using a refrigeration cycle — the same process as your air conditioner, run in reverse. Because it's moving heat rather than generating it, it can deliver 200–400% of the energy it consumes as electricity.
That distinction is why the comparison isn't straightforward. A heat pump is dramatically more efficient in principle, but efficiency is only half the equation — the other half is what a unit of electricity costs versus a unit of gas where you live.
Running cost: it depends on local utility rates
This is the single most decisive factor and it's entirely local.
The rough calculation: compare the cost per therm of natural gas against the cost per kWh of electricity in your area, factoring in the heat pump's coefficient of performance at your typical winter temperatures.
Broad patterns we see:
- Cheap natural gas, expensive electricity — a high-efficiency gas furnace usually wins on running cost.
- Expensive propane or oil, moderate electricity — a heat pump nearly always wins, often dramatically. Propane in particular is expensive enough that heat pumps frequently pay back their installation cost in a handful of years.
- Moderate gas, cheap electricity — close enough that other factors decide it.
- No gas line to the property — a heat pump is almost certainly the right answer versus propane, oil or electric resistance heat.
Any contractor quoting you a system should be willing to run this calculation with your actual utility rates. If they won't, that's informative.
Cold weather: what actually changed
The old objection was that heat pumps stop working in cold weather. That was fair about older equipment and is largely obsolete for current cold-climate models.
Standard heat pumps lose capacity as outdoor temperature drops, and older units became impractical below roughly 30°F, falling back on electric resistance backup heat — which is expensive.
Modern cold-climate heat pumps use variable-speed inverter compressors and maintain useful capacity well below freezing. Many hold rated capacity to 5°F and continue operating meaningfully below that.
The practical question isn't "does it work in the cold" but "how many hours per year is it below the temperature where my backup heat takes over, and what does that backup cost to run?" For most of the continental US, that's a small fraction of the heating season.
Dual-fuel systems resolve this directly: a heat pump paired with a gas furnace, with controls that switch to gas below whatever outdoor temperature makes gas cheaper. You get heat pump efficiency for the large majority of the season and furnace capability for the coldest stretch. It's the most expensive option upfront and often the cheapest to run.
Upfront cost
Rough installed ranges, which vary considerably by region and home:
| System | Typical installed cost |
|---|---|
| Gas furnace only | $4,000 – $7,500 |
| Gas furnace + separate AC | $8,000 – $14,000 |
| Heat pump (heating + cooling) | $7,000 – $14,000 |
| Cold-climate heat pump | $10,000 – $18,000 |
| Dual-fuel system | $12,000 – $20,000 |
The important comparison is often missed: a heat pump replaces both your furnace and your air conditioner in one system. If you need cooling anyway — and most people do — compare the heat pump against the furnace-plus-AC total, not against the furnace alone. On that basis the numbers look very different.
Federal and state incentives can also shift this materially. Heat pumps qualify for tax credits and utility rebates in most areas that furnaces don't, sometimes worth several thousand dollars. Those programs change frequently, so check current terms rather than relying on an article.
Lifespan and maintenance
A furnace typically lasts 15–20 years; a heat pump 12–15. The gap exists because a heat pump runs year-round — it's your air conditioner too — while a furnace sits idle for half the year.
Both need annual service. Heat pumps need it in both spring and fall, since the same equipment handles both seasons.
What tends to decide it
In practice, the answer usually falls out of a few specific facts about your home:
Lean heat pump if: you have no gas line; you heat with propane or oil; your electricity is reasonably priced; you need to replace an aging AC anyway; you want to reduce combustion in the home; or you're eligible for substantial local rebates.
Lean furnace if: natural gas is cheap where you are; your existing AC is relatively new and doesn't need replacing; you live somewhere with sustained deep-winter temperatures and no budget for cold-climate equipment; or your ductwork can't handle the higher airflow volumes heat pumps need.
Lean dual-fuel if: you have gas available, want the lowest running cost across the whole season, and the upfront premium fits the budget.
The part people skip
Whichever you choose, the installation matters more than the equipment.
An oversized system short-cycles and never dehumidifies properly. Undersized ductwork strangles airflow and destroys the efficiency you paid for. A heat pump with an incorrect refrigerant charge can lose a large share of its rated capacity — and charge is set on installation day.
We run a Manual J load calculation on every replacement quote for exactly this reason. It's the difference between the efficiency rating on the box and the efficiency you actually get. Any quote that sizes a system from square footage alone is a guess, and it's the most expensive kind of guess in this trade.
If you're weighing a replacement, get the load calculation and the utility-rate comparison in writing before you compare prices. Those two documents make the decision considerably clearer than any general article can.