A heat pump is one of the few home appliances that seems to break the laws of physics: it can deliver three or four units of heat for every unit of electricity it consumes. It does this not by generating warmth the way a furnace or electric baseboard does, but by moving heat that already exists from one place to another. That single distinction explains almost everything about how heat pumps perform, what they cost to run, and where they make sense. This article walks through the underlying mechanism, the main equipment types, how the technology now copes with genuine cold, the efficiency ratings on the labels, realistic cost drivers, and where a heat pump is the obvious choice versus where it is not. It is general information, not financial or engineering advice; any specific project should be evaluated against local energy rates, current incentives, and professional contractor quotes.
Moving Heat Instead of Making It
A furnace creates heat by burning natural gas, propane, or oil, and an electric resistance heater creates it by forcing current through a coil. A heat pump does neither. It uses electricity to run a compressor and circulate a refrigerant through a closed loop, extracting heat from the outside air or ground and releasing it indoors [1]. The same hardware runs in reverse: a reversing valve changes the direction of refrigerant flow for the cooling and defrost cycles, so in summer the system pulls heat out of the house and dumps it outdoors, which is exactly how a conventional air conditioner already works [1].
The reason a heat pump can be more than 100 percent efficient is that it is not converting electricity into heat at all; the electricity only powers the transfer. Because there is far more low-grade heat available in cold outdoor air than people intuitively expect, a well-designed unit delivers two to four times more heat energy than the electrical energy it consumes. This is measured as the coefficient of performance, or COP. A COP of 4 means four units of heat out for every unit of electricity in. The International Energy Agency notes that the COP of a typical household heat pump is around four, which makes current models roughly three to five times more energy efficient than a natural gas boiler [2].
The Three Main Types
Heat pumps are usually grouped by where they draw heat from and how they distribute it inside the home. The practical differences come down to installation complexity, cost, and how steady the heat source is.
- Air-source heat pumps are the most common and least expensive. They pull heat from outdoor air and distribute it through conventional ductwork, making them a natural replacement for a central furnace and air conditioner combination [1].
- Ductless mini-split systems are a variant of the air-source design that skip ductwork entirely, using one or more wall-mounted indoor units connected to an outdoor compressor. They require minimal construction and suit additions, smaller homes, and spaces where running ducts is impractical, though they do not offer the high-MERV filtration of a ducted system [1].
- Ground-source heat pumps, also called geothermal, exchange heat with the earth through buried loops rather than with outdoor air. A few feet down, ground temperature stays relatively constant year-round, typically in the range of about 40 to 70 degrees Fahrenheit, which is warmer than winter air and cooler than summer air [3].
Because the ground is a more stable heat source than the air, geothermal systems tend to be quieter, longer-lived, and more efficient than air-source equipment, and their performance does not swing with the outdoor temperature [3]. The tradeoff is installation: drilling or excavating the ground loop can cost several times as much as an equivalent air-source system [3].
Cold-Climate Performance Has Changed
The most persistent myth about heat pumps is that they stop working when it gets cold. That was largely true of older single-speed models, which lost capacity as temperatures dropped and leaned heavily on backup electric resistance heat. Modern cold-climate units are different: they use inverter-driven, variable-speed compressors that ramp output up and down to match demand and maintain useful heat output well below freezing.
The evidence on this is now field-based rather than theoretical. The National Renewable Energy Laboratory monitored a dozen variable-capacity, centrally ducted heat pumps in single-family homes across cold-climate locations, eleven in the northwestern United States and one near Denver, through a full winter, documenting how the equipment performs in real conditions rather than in a lab [4]. At the national level, the IEA points out that heat pumps are already the dominant heating technology in some of the coldest places on Earth: around 60 percent of buildings in Norway use them, and adoption exceeds 40 percent in Sweden and Finland [2]. Those adoption rates are difficult to reconcile with the idea that the technology cannot handle cold weather.
What the Efficiency Ratings Actually Mean
Heat pump labels carry a few standardized numbers, and as of January 2023 the United States updated its rating system to the "2" versions to reflect more realistic testing conditions [1]. Knowing what each one measures makes the spec sheet far easier to read.
- SEER2 measures cooling efficiency over a season: the total cooling delivered divided by the electricity used. Higher is better.
- HSPF2 measures heating efficiency over a season, again as heat delivered per unit of electricity. Higher is better.
- COP is the instantaneous ratio of heat output to electrical input at a given outdoor temperature, and it is the metric most often quoted for cold-weather performance.
The rating changeover shifted the absolute numbers without changing the underlying equipment, so a unit formerly rated at 15 SEER became roughly 14.3 SEER2, and an 8.8 HSPF became about 7.5 HSPF2 [1]. For cold-climate buyers, the most telling figure is low-temperature COP. To earn ENERGY STAR's cold-climate recognition, for example, a unit must maintain a COP of at least 1.75 and retain 70 percent of its heating capacity at 5 degrees Fahrenheit compared with its capacity at 47 degrees [5]. That is a useful benchmark when comparing models for a genuinely cold region.
Real-World Costs and What Drives Them
Installed cost varies widely by home, region, equipment tier, and the state of the existing ductwork, so any single price quoted online should be treated as a rough anchor rather than a quote. The factors that move the number most are the size and layout of the home, whether usable ducts already exist, the efficiency tier and cold-climate rating of the unit, and local labor rates. Ground-source systems sit at the high end because of the ground-loop installation, which can run several times the cost of comparable air-source equipment [3].
The operating-cost side is where heat pumps earn their keep, and the savings depend heavily on what is being replaced. A Northeast Energy Efficiency Partnerships analysis cited by the Department of Energy found annual savings of roughly 3,000 kilowatt-hours, about 459 dollars, compared with electric resistance heating, and around 6,200 kilowatt-hours, about 948 dollars, compared with oil heat [1]. Geothermal systems carry the highest upfront cost but the lowest running cost; the Department of Energy estimates the price premium is often recovered in energy savings within roughly 5 to 10 years, depending on local energy prices and incentives [3]. The economics of any specific project should be evaluated against current local rates and contractor quotes rather than national averages.
Incentives Exist, but Verify Them Yourself
Heat pumps are frequently eligible for federal tax credits, state programs, and utility rebates, and these can meaningfully change the payback math. The Department of Energy explicitly frames geothermal payback as dependent on the cost of energy and available incentives in your area, underscoring that the benefit is real but location-specific [3]. The catch is that these programs change often: eligibility criteria, dollar amounts, and qualifying equipment lists are revised from year to year, and some are capped or time-limited.
For that reason, the only reliable approach is to confirm what is currently available before committing. Check the official federal energy guidance, your state energy office, and your own utility, and verify that the specific model you are considering appears on the relevant qualified-product list. Treat any incentive figure in an article, including this one, as a starting point to verify rather than a guarantee.
When a Heat Pump Makes Sense, and When It Might Not
A heat pump is most compelling when it can replace two systems at once. Because a single unit both heats and cools, households that would otherwise buy a furnace and a separate air conditioner often find the comparison favorable, and the case is strongest for anyone currently heating with electric resistance, oil, or propane, where running-cost savings are largest [1]. Homes with reasonable insulation and air-sealing also see better results, since a well-sealed envelope lets a right-sized unit carry the load.
The picture is more nuanced in a few situations. Where electricity is expensive relative to very cheap natural gas, the operating-cost advantage narrows. Poorly insulated or leaky homes will underperform until the envelope is improved. And in the most extreme climates, equipment should be specifically rated for cold-climate operation, with backup heat sized appropriately, rather than a standard model pressed into service. Pairing a heat pump with a backup heat source for the coldest hours is a common way to handle the most demanding conditions efficiently while keeping the heat pump as the primary system.
The Bottom Line
The core appeal of a heat pump is straightforward physics: moving heat is far cheaper than making it, which is why one unit of electricity can deliver three to five units of heat over a heating season [2]. The technology now works in genuinely cold climates, as both NREL field data and Nordic adoption rates demonstrate [4][2]. The honest caveats are about money and fit rather than capability: costs vary by home and region, the best savings come from replacing expensive fuels, and incentives shift, so they should be verified at the source. For a household weighing its next system, the practical move is to compare cold-climate-rated equipment on its SEER2, HSPF2, and low-temperature COP, get local installed quotes, and check current incentives before deciding.
Sources
[1] U.S. Department of Energy: Air-Source Heat Pumps — https://www.energy.gov/energysaver/air-source-heat-pumps
[2] International Energy Agency: The Future of Heat Pumps (Executive Summary) — https://www.iea.org/reports/the-future-of-heat-pumps/executive-summary
[3] U.S. Department of Energy: Geothermal Heat Pumps — https://www.energy.gov/energysaver/geothermal-heat-pumps
[4] National Renewable Energy Laboratory: Minimizing Auxiliary Heat Use for Cold Climate Operation of Air Source Heat Pumps — https://docs.nrel.gov/docs/fy25osti/91366.pdf
[5] ENERGY STAR: Air-Source Heat Pumps Key Product Criteria — https://www.energystar.gov/products/heating_cooling/heat_pumps_air_source/key_product_criteria
