A heat pump heating system is an electric appliance that moves heat from outdoor air or the ground into your home, rather than generating heat by burning fuel. It works on the same principle as a refrigerator or air conditioner, just in reverse: instead of pulling heat out of a space and dumping it outside, it pulls heat from outside and delivers it indoors. Because it moves existing heat rather than creating it from scratch, a heat pump can deliver two to three times more heating energy than the electricity it consumes.
How a Heat Pump Moves Heat
A heat pump uses a loop of refrigerant, a fluid that easily shifts between liquid and gas states, to carry heat from one place to another. The process has four stages, each driven by a specific component.
First, liquid refrigerant flows through an outdoor coil called the evaporator. Even in cold air, there’s thermal energy available, and the refrigerant absorbs it, turning from a cold liquid into a low-pressure gas. That gas then enters the compressor, which squeezes it into a much smaller volume. Compressing the gas raises both its pressure and temperature dramatically. The now-hot, high-pressure gas flows into an indoor coil called the condenser, where it releases its heat into your home’s air supply and cools back down into a liquid. Finally, the liquid passes through an expansion valve that drops its pressure, cooling it further and preparing it to absorb heat again as it cycles back to the outdoor coil.
This loop runs continuously while the system is heating. The key insight is that the compressor is the only part doing heavy electrical work. The heat itself comes from the outdoor environment for free.
How It Switches Between Heating and Cooling
Most heat pumps double as air conditioners. A component called a reversing valve changes the direction refrigerant flows through the system. In heating mode, the outdoor coil absorbs heat and the indoor coil releases it. When your thermostat calls for cooling, the reversing valve flips the flow so the indoor coil absorbs heat from your house and the outdoor coil dumps it outside. You get year-round climate control from a single system.
Types of Heat Pumps
Air-Source Heat Pumps
Air-source systems are by far the most common. They pull heat from outdoor air and are available in two main configurations. Ducted systems connect to your home’s existing ductwork with an outdoor unit and an indoor air handler. Ductless mini-split systems skip the ducts entirely, using one or more wall-mounted indoor units connected to an outdoor compressor by refrigerant lines. Mini-splits are popular retrofits for homes with radiators, baseboard heat, or room additions where running ductwork isn’t practical.
Ground-Source (Geothermal) Heat Pumps
Ground-source systems draw heat from below the earth’s surface through underground piping loops. Because soil temperature stays relatively constant year-round, these systems don’t struggle with extreme cold the way some air-source units can. They’re quieter, last longer, need less maintenance, and can even heat your household water using a built-in component called a desuperheater. The tradeoff is cost: purchasing and installing a geothermal system is significantly more expensive due to the underground piping. Indoor components typically last around 25 years, and the ground loop itself can last 50 years or more.
Cold Climate Performance
Older heat pumps lost significant capacity in freezing weather, giving the technology a reputation for being ineffective in northern climates. That’s no longer accurate. Modern cold-climate heat pumps are engineered to maintain strong output well below freezing. To earn ENERGY STAR’s cold climate designation, a heat pump must retain at least 70% of its rated heating capacity at 5°F and maintain a coefficient of performance (a measure of efficiency) of at least 1.75 at that temperature, meaning it still delivers more heat energy than the electricity it uses.
According to the U.S. Department of Energy’s Building America program, a properly sized cold-climate heat pump can meet 100% of a home’s heating load in nearly any location in the United States. In cities like Minneapolis, the right unit can handle design heating conditions without relying on backup heat at all.
Dual-Fuel and Backup Systems
Some homeowners pair a heat pump with a gas furnace in what’s called a dual-fuel system. A smart thermostat monitors outdoor conditions and automatically switches between the two. During mild and moderately cold weather, the heat pump handles heating. When temperatures drop to a preset point, often around 40°F, the furnace takes over. That switchover temperature is adjustable based on whether you want to optimize for comfort, efficiency, or cost.
This setup can make sense in regions with very cold winters and low natural gas prices, since the furnace provides a safety net during the coldest stretches while the heat pump covers the majority of heating hours at lower operating cost.
Efficiency Ratings
Heat pump heating efficiency is measured using a metric called HSPF2 (Heating Seasonal Performance Factor). Higher numbers mean more heat per unit of electricity. To earn the ENERGY STAR label, a split-system heat pump needs an HSPF2 of at least 7.8. Cold-climate ducted models must hit 8.1, and cold-climate ductless models must reach 8.5. For cooling, the standard metric is SEER2, with a minimum of 15.2 for ENERGY STAR certification.
In practical terms, even a baseline ENERGY STAR heat pump delivers far more heating per dollar of electricity than electric baseboard heaters or a standard electric furnace, which convert electricity to heat at a 1:1 ratio.
Cost Savings
How much you save depends heavily on what you’re replacing. The average U.S. household saves about $370 per year after switching to a heat pump. If you’re coming from fuel oil, propane, or electric resistance heating (baseboard heaters, electric furnaces), savings can reach $1,000 per year. Switching from natural gas, on the other hand, doesn’t save much on average at current fuel prices, though that varies by region and gas rates.
On the federal incentive side, heat pumps that meet the highest efficiency tier qualify for a tax credit of up to $2,000 per year through the Energy Efficient Home Improvement Credit, which covers equipment and installation labor. This credit is available for improvements made through December 31, 2025, and applies to your primary residence. Many states and utilities offer additional rebates on top of the federal credit.
Lifespan and Maintenance
A typical heat pump lasts 10 to 15 years. Well-maintained premium models can reach 15 to 20 years, while lower-tier systems may last only 8 to 12 years. Because heat pumps run year-round for both heating and cooling, they log more operating hours than a furnace or standalone air conditioner, which makes maintenance especially important.
The most impactful thing you can do is replace the air filter every one to three months, depending on usage. Clogged filters restrict airflow, force the system to work harder, and accelerate wear. Beyond that, schedule one professional tune-up per year. A technician will inspect the coils, check refrigerant levels, test electrical connections, and verify airflow. These annual visits catch small problems before they become expensive repairs and help the system maintain its efficiency over time.