A heat pump moves warmth instead of making it from scratch
A heat pump is an appliance that pulls heat from outside air, ground, or water and moves it indoors to warm your home. In summer, it reverses and pulls heat out of your house to cool it. This is different from a furnace, which burns fuel to create heat. A heat pump uses electricity to move existing heat around, which is why it can heat and cool with the same equipment.
The basic idea is straightforward: heat exists everywhere, even in cold air. A heat pump captures that heat using refrigerant (a special fluid that changes between liquid and gas), compresses it to make it hotter, and releases it inside your home. When you switch to cooling mode, the same cycle runs backward.
Key Takeaways
- Heat pumps move heat from outside to inside in winter and reverse the process in summer, using the same equipment for both heating and cooling.
- Air-source heat pumps are the most common type and work even in cold climates, though efficiency drops as outdoor temperature falls.
- Ground-source and water-source heat pumps are more efficient but cost more to install because they require digging or water access.
- Heat pumps use less electricity than electric resistance heating or air conditioning alone, which can lower your utility bills.
- Installation requires a licensed technician and may need ductwork changes or new indoor equipment, so budget for professional assessment.
How the refrigerant cycle moves heat
Inside a heat pump, refrigerant flows through four main parts: an evaporator, a compressor, a condenser, and an expansion valve. In heating mode, the evaporator sits outside and absorbs heat from the air (or ground). The refrigerant boils and becomes a gas, even though the outside air is cold. The compressor then squeezes this gas, which makes it much hotter—hot enough to warm your home.
The hot, pressurized gas flows to the condenser inside your house, where it releases heat into your indoor air or water. As the refrigerant cools, it turns back into a liquid. The expansion valve then lowers the pressure, and the cycle starts over. In cooling mode, the evaporator and condenser swap roles: the indoor unit pulls heat out of your house, and the outdoor unit releases it outside.
This cycle is the same one used in refrigerators and air conditioners, except a heat pump can run it in both directions. That reversibility is what makes it useful for year-round comfort.
Air-source, ground-source, and water-source types
Air-source heat pumps pull heat from outdoor air and are the most common type. They work in most climates, including cold ones, though their efficiency drops when the outdoor temperature falls below freezing. Many modern air-source models can still heat effectively at temperatures as low as −13°F (−25°C), but they work best when outdoor air is above 32°F (0°C). They are cheaper to install than other types because they do not require digging or water connections.
Ground-source heat pumps (also called geothermal) bury pipes underground where the temperature stays steady year-round, usually between 45°F and 75°F (7°C to 24°C) depending on your location. Because the ground is warmer than winter air and cooler than summer air, ground-source systems are more efficient than air-source. However, installation requires excavation, which costs significantly more and takes longer. Ground-source systems are best for homeowners who plan to stay in their home for many years.
Water-source heat pumps work similarly to ground-source but use a pond, lake, or well instead of buried pipes. They are efficient but only practical if you have a suitable water source on your property. Installation costs are similar to ground-source systems.
Efficiency and how it compares to other heating
Heat pumps are measured by a number called HSPF (Heating Seasonal Performance Factor) for heating and SEER (Seasonal Energy Efficiency Ratio) for cooling. Higher numbers mean more efficient. A modern air-source heat pump typically has an HSPF of 8 to 10 and a SEER of 14 to 20. Ground-source systems often reach HSPF values of 10 to 15 because the ground temperature is more stable.
Compared to electric resistance heating (like baseboard heaters or electric furnaces), a heat pump uses 50 to 70 percent less electricity to produce the same warmth. Compared to a gas furnace, the savings depend on your local electricity and gas prices, but in many regions a heat pump costs less to operate. A heat pump also cools your home, so you do not need a separate air conditioner.
The trade-off is that heat pumps work best when they run continuously at a low level rather than cycling on and off. If your home is poorly insulated or you live in an extremely cold climate, you may need a backup heating source (called auxiliary heat) on the coldest days, which uses more electricity.
Installation and what to expect
Installing a heat pump requires a licensed HVAC technician. For an air-source system, the outdoor unit is mounted on the ground or wall, and refrigerant lines connect it to an indoor unit. If you have existing ductwork, the indoor unit can connect to it. If you do not have ducts, the technician will install a ductless (mini-split) system with wall-mounted or ceiling-mounted indoor units in each room or zone you want to heat and cool.
Ground-source installation is more involved. A drilling crew digs vertical boreholes (usually 150 to 300 feet deep) or digs horizontal trenches and buries loops of pipe. The pipes connect to an indoor unit in your basement or mechanical room. This process takes several days to a week and costs more than air-source installation.
Before installation, a technician should assess your home's insulation, air sealing, and ductwork (if you have it). Poor insulation or air leaks reduce heat pump efficiency, so addressing those first can improve performance and lower operating costs. Many installers offer a free or low-cost assessment.
Maintenance and how long they last
Heat pumps require less maintenance than furnaces because they have no combustion and no fuel lines. You should have the system serviced once a year, ideally before the heating season starts. Routine service includes checking refrigerant levels, cleaning or replacing air filters, inspecting electrical connections, and testing the reversing valve (which switches between heating and cooling modes).
The outdoor unit should be kept clear of leaves, snow, and debris. In winter, some snow or frost on the outdoor coil is normal, and the system will defrost itself automatically. However, if snow piles up around the unit, clear it away to keep airflow open.
A well-maintained heat pump typically lasts 15 to 20 years. The compressor, which is the most expensive part to replace, usually lasts the life of the system. If a compressor fails after the warranty expires, replacement can cost $1,500 to $3,000 or more, depending on the system size and type.
When a heat pump makes sense for your home
A heat pump is a good fit if you want a single system for heating and cooling, live in a climate where winter temperatures rarely drop below −13°F (−25°C), and plan to stay in your home long enough to recoup the installation cost through lower utility bills. In mild climates, payback can happen in 5 to 8 years. In colder climates, it may take 10 to 15 years, or longer if you have low electricity rates.
A heat pump is less practical if your home is very poorly insulated and you cannot afford to improve it, if you live in an extremely cold climate and cannot afford backup heating, or if you rent and cannot make permanent changes. In those cases, a traditional furnace or baseboard heating may be more cost-effective.
If you are replacing an air conditioner, adding a heat pump is often cheaper than keeping the AC and adding a separate heating system, because you eliminate the AC unit and use one system year-round.
Frequently Asked Questions
Do heat pumps work in cold climates?
Yes. Modern air-source heat pumps can heat homes even when outdoor temperatures are well below freezing. Efficiency drops as it gets colder, but most models work down to −13°F (−25°C) or lower. Ground-source heat pumps are even more efficient in cold climates because ground temperature stays steady. If you live in an extremely cold region, you may need auxiliary heating on the coldest days.
How much does a heat pump cost to install?
Air-source heat pump installation typically costs $4,000 to $8,000 for a single-zone ductless system or $5,000 to $12,000 if you need ductwork modifications. Ground-source systems cost $15,000 to $30,000 or more because of excavation. Costs vary by region, system size, and whether your home already has ducts. Get quotes from at least two licensed installers.
Will a heat pump lower my heating and cooling bills?
In most cases, yes. Heat pumps use 50 to 70 percent less electricity than electric resistance heating and often cost less to operate than gas furnaces, depending on local energy prices. However, savings depend on your current heating method, home insulation, and how much you heat and cool. A technician can estimate your potential savings based on your home and local utility rates.
Can I use a heat pump with my existing furnace?
Yes. Many homeowners install a heat pump for cooling and spring/fall heating, then use their existing furnace as backup on the coldest winter days. This hybrid approach can reduce heating costs while keeping a reliable backup. Your HVAC technician can set up the system to switch automatically based on outdoor temperature.
What is the difference between a heat pump and an air conditioner?
An air conditioner only cools—it pulls heat out of your home and releases it outside. A heat pump does both: it cools in summer and reverses to heat in winter. If you need both heating and cooling, a heat pump is more efficient than running an AC and a separate heater.