Heat Pumps Are Effective in Cold Weather. Most Americans Still Don't Know It.
Quick answer: modern cold-climate heat pumps keep homes warm well below zero. Mitsubishi Hyper-Heating INVERTER equipment delivers 100% of its rated heat at 5°F and operates to -13°F, with H2i Plus models reaching -22°F, and Maine, one of the coldest states, has rebated well over 100,000 of them. The belief that heat pumps stop working at 30°F or 40°F comes from the first-generation equipment of the 1970s and 80s, built for the South. Inverter-driven compressors changed that more than a decade ago. "Do heat pumps work in cold weather?" is still one of the most searched questions about them, which is why we keep answering it from Ticonderoga, where the design temperature is -10°F.
The "most neglected" climate solution
Heat pumps, all-electric systems that heat and cool, have been called the most overlooked tool for cutting home heating emissions. Worldwide installations have climbed for years, and because they run on electricity they can be powered by renewables. In 2022, with Europe scrambling to cut dependence on imported gas, heat pumps were even proposed as an export to help wean the continent off it.
In the United States, though, the technology still carries a reputation from a different era: that it is useless once the temperature drops into the 30s. That was true of the equipment sold in Georgia and the Carolinas forty years ago. It is not true of a Mitsubishi Hyper-Heat system in Keene Valley today.
What an air-source heat pump actually is
An air-source heat pump is an air conditioner that can run in reverse. In summer it pulls heat out of the house and pushes it outdoors. In winter it pulls heat out of the outdoor air and pushes it inside. (Geothermal and water-source heat pumps do the same with the ground or a well.) A 2020 survey found nearly half of Northeastern homeowners had never heard of a heat pump, which says a lot about why the myth survives.
The reason heat pumps are so efficient is that they move heat rather than create it. A gas or oil furnace can never exceed about 95% efficiency because it is burning fuel. A heat pump routinely delivers 300% to 400%: three to four units of heat for every unit of electricity, because the electricity only runs a compressor and fans. See our plain-English heat pump guide.
Why they struggled years ago
The first generation of heat pumps was built for the South: places that needed air conditioning most of the year and only a little heat. They used single-speed compressors that could not pull enough heat from cold air, so once the outdoor temperature fell much below freezing they handed off to electric resistance strips. Those systems gained ground, in the words of one Minnesota researcher, "in places where it wasn't cold."
The technology that changed the answer
Over the last decade and more, manufacturers introduced inverter-driven variable-speed compressors. The compressor speeds up as the outdoor temperature drops, so it can keep moving heat out of very cold air. Mitsubishi added a flash-injection refrigerant circuit so the compressor can run at those speeds without damage, and a smart defrost cycle. The result is equipment rated to keep a house comfortable far below zero. There is still heat energy in air at -20°F; the question is only whether the machine can collect it efficiently, and modern cold-climate units do.
Mitsubishi's published numbers: 100% of rated heating capacity at 5°F, continued operation to -13°F on standard Hyper-Heating INVERTER equipment, and -22°F on H2i Plus models. Efficiency falls as it gets colder, but a cold-climate unit still delivers well over one unit of heat per unit of electricity on the coldest nights, which electric baseboard can never do.
Research has found heat pumps can cut household CO2 emissions in roughly 70% of U.S. homes, with the biggest benefit for homes heated by fuel oil or inefficient electric heat, which describes most of the North Country. States with the harshest winters, including New York, have responded with rebate programs: NYS Clean Heat pays incentives through NYSEG and National Grid for qualifying cold-climate heat pumps.
What Maine proved
Efficiency Maine, the state's independent efficiency agency, spent a decade dispelling the cold-weather myth in one of the coldest states in the country. Its program manager described two kinds of Mainers in 2012: those who had never heard of heat pumps, and those who "knew" they did not work in the cold. The agency recruited installers, publicized field results and paid rebates. Adoption started in northern Maine, a tightly connected region where neighbors told neighbors, and spread. Maine has since rebated more than 100,000 heat pumps in a state with fewer than 600,000 occupied homes, a per-capita rate higher than most of Europe.
The economics drove it. Most Maine homes heat with oil or propane, the same as the Adirondacks. Efficiency Maine's analysis put the cost of running a heat pump at roughly a third the cost of propane heat and half the cost of oil, saving households up to several thousand dollars a year. A 2017 Minnesota field study found hundreds of dollars a year in savings even against gas and standard electric systems. As the program manager put it, Maine now has "almost 100,000 salesmen" who already own one.
Not just Maine
Minnesota's Center for Energy and Environment partnered with utilities to push adoption and keeps a list of qualified installers. The Northeast Energy Efficiency Partnerships publishes a list of air-source heat pumps verified to perform in Northeastern winters, which is the list NYS Clean Heat draws on. Homes are being heated with heat pumps in Alaska, where winter highs average in the low 20s. If the equipment carries a house in Fairbanks and Caribou, it carries one in Saranac Lake.
How we size for cold weather
The myth survives partly because some heat pumps really do underperform: not because the technology fails, but because an installer sized them from square footage instead of heat loss, or chose a model whose capacity collapses below 10°F. We do it differently:
| Step | What it means for your house |
|---|---|
| Room-by-room load calculation | Heat loss at the local design temperature (-10°F in Ticonderoga, colder in the High Peaks), not a rule of thumb |
| Capacity table check | We read the chosen outdoor unit's rated output at 5°F, -5°F and -13°F and compare it to the load, not the nameplate at 47°F |
| Hyper-Heat equipment only | Standard H2i to -13°F; H2i Plus to -22°F for Lake Placid, Saranac Lake and Tupper Lake |
| Snow-ready install | Outdoor unit on a stand or bracket above drift height, drainage planned for defrost water |
| Backup conversation | An honest answer on whether a woodstove or existing boiler is worth keeping for the coldest nights |
That process, plus a 12-year Diamond Contractor ELITE parts warranty and our 180-Day Comfort Guarantee, is how we stand behind the claim that heat pumps work here. See load calculations and how our installation works.
The honest caveats
- Installer experience matters. Some contractors are still uncomfortable with heat pumps and price in that uncertainty, or size and install them poorly. A Mitsubishi Diamond Contractor ELITE has the training and the volume to get it right.
- Backup is a design question, not a given. Many Maine homes keep a woodstove as backup for extreme nights or power outages. In the High Peaks we discuss the same; around Lake Champlain a properly sized H2i system usually needs none.
- The envelope still counts. A leaky 1850s farmhouse needs air sealing before any heating system performs well.
- Up-front cost is higher than a furnace swap. NYS Clean Heat rebates, 0% financing and lower operating costs close the gap, but it is a bigger first check.
What we see in the Adirondacks
Our customers are the local version of Maine's story. A family in a 200-year-old Adirondack house switched from oil and reported their home "has never been so warm." A Hague customer heats a 30-by-40-foot insulated metal building with a single wall unit and says it "handles it great." A Newcomb cabin, a first home in Ticonderoga, farmhouses in Crown Point and Westport: the equipment carries them through January. The word spreads the same way it did in Maine, one neighbor at a time. Read more in our reviews and on the cold-climate heat pump page, and see what we design for in Lake Placid, where -20°F is routine.
If you heat with oil or propane in the North Country and have been told heat pumps do not work here, the people telling you are a decade behind. Check the numbers for your own home with our savings calculator or see current rebates.
Frequently asked questions
Do heat pumps work below freezing?
Yes. Modern cold-climate heat pumps with inverter compressors keep heating far below freezing. Mitsubishi Hyper-Heating delivers full rated capacity at 5°F and operates to -13°F, or -22°F on H2i Plus models.
Why do people think heat pumps don't work in cold weather?
Because first-generation heat pumps of the 1970s and 80s were built for the South with single-speed compressors and lost capacity well above zero. Inverter-driven cold-climate equipment solved that more than a decade ago, but the reputation lingers.
Is a heat pump cheaper to run than oil or propane in the North Country?
In nearly every case, because it moves about three units of heat per unit of electricity rather than burning fuel. Efficiency Maine found heat pumps cost roughly a third as much to run as propane and half as much as oil; our calculator shows your home's numbers.
Do I need a backup heating system with a cold-climate heat pump?
Not necessarily. A Mitsubishi H2i system sized to your home's heat loss carries most North Country homes on its own. In the High Peaks, where -25°F happens, many homeowners keep a woodstove or the old boiler for the rare extreme night or a power outage.
Talk to us
Have questions about your home? Call Adirondack Heat Pumps at (518) 812-1958, stop by the showroom at 15 Montcalm Street in Ticonderoga, or request a free in-home estimate. We serve Essex County, the Lake George and Lake Champlain shores, the High Peaks and Addison County, Vermont.