"Heat pumps don't work in the cold" was true a decade ago. Modern cold-climate models changed that — but there are real caveats worth knowing before you switch. General info, not a substitute for a load calculation.
A heat pump doesn't burn fuel — it moves heat from outside air into your home, which is why it's so efficient. Older units lost capacity as it got colder because there's less heat to grab. That's the origin of the myth, and it's exactly the part that modern designs fixed.
Newer 'cold-climate' heat pumps use variable-speed compressors and better refrigerants that keep useful heat output well below freezing — many are rated to hold capacity down to around −15°C/5°F and keep running lower. In most winters, a properly sized cold-climate unit heats the whole house on its own.
When you compare units, two numbers matter more than the headline efficiency. First, the rated heating capacity at a low temperature (say 5°F), not just at 47°F — capacity always drops as it gets colder, so you want the cold-hour figure. Second, the COP (coefficient of performance) at that temperature, which tells you how much heat you get per unit of electricity. A unit that still delivers a COP above 2 near 5°F is genuinely a cold-climate machine, not just one with the label.
In a genuinely severe cold snap, or in a leaky, poorly insulated house, output can dip below what you need on the very coldest hours. That's why cold-climate installs often pair the heat pump with backup (electric resistance strips or an existing furnace) that only kicks in on those rare extremes — you run efficient 95% of the winter and covered for the rest.
A heat pump that's undersized — or a house that leaks heat — will struggle no matter the model. Get a proper load calculation and seal/insulate first; a right-sized unit in a tight house sails through winter, while an oversized one in a drafty house short-cycles and disappoints. The install decides the outcome as much as the equipment.
If you have good existing ductwork, a ducted (central) heat pump can replace a furnace one-for-one. If your ducts are leaky, undersized, or absent, ductless mini-splits — wall units that serve one or a few rooms — often heat more efficiently and let you zone the house room by room. Many cold-winter homes end up with a hybrid: mini-splits for the main living areas plus a little backup for bedrooms or the coldest snaps.
Running cost depends on your local electricity and gas prices, but the efficiency math is stark: a heat pump delivers roughly two to four units of heat per unit of electricity, while even a high-efficiency gas furnace tops out near one unit of heat per unit of fuel. Where electricity isn't wildly expensive relative to gas, a heat pump usually costs less to run — and far less than oil, propane, or electric-resistance baseboard. Plug your own rates into the comparison before assuming.
Heat pumps are one of the most heavily incentivized home upgrades right now. Federal tax credits, state and utility rebates, and low-income programs can knock a large chunk off the install — sometimes thousands of dollars. These change often and vary by region, so check your utility's website and your local or national energy program before you gather quotes. The sticker price and the price after incentives can be very different numbers.
A heat pump is usually a strong fit if most of these are true — but confirm with a pro who runs an actual load calculation: