A heat pump uses refrigeration principles to move heat into or out of a home, providing both heating and cooling efficiently.
Air-Source Heat Pumps
Ground-Source Heat Pumps
Groundwater Heat Pumps
How It Heats and Cools
Heat pumps work much like refrigerators, but in reverse. Instead of creating heat, they move it from one place to another. That allows one system to both heat and cool a home.
The most common type is an air-source heat pump, but some systems draw heat from the ground or groundwater instead.
Air-Source Heat Pumps
Air-source heat pumps are the most common residential type. A split system includes:
- An outdoor unit with a compressor, coil, fan, and reversing valve
- An indoor unit with a blower and indoor coil
- Refrigerant lines connecting the two
Depending on whether the system is in heating or cooling mode, the refrigerant makes the indoor coil either warm or cool. A blower pulls room air through a filter and across that coil, then sends conditioned air through the ductwork to your rooms.
Many systems also include an auxiliary electric-resistance heating element to help during very cold weather.
Split air-source heat pump diagram.
A package system combines both indoor and outdoor components in one cabinet, typically installed outdoors or on a roof.
Package air-source heat pump.
Heat pumps usually deliver gentler heat than a gas furnace, so they tend to run longer cycles and circulate air more continuously. On very cold days, the supplemental heater may switch on to help maintain comfort.
How It Heats and Cools
- Heating mode: The system extracts heat from outside air and moves it indoors
- Cooling mode: The system removes heat from indoor air and releases it outside
This heat-transfer process is what makes heat pumps efficient, especially in moderate climates.
Ground-Source Heat Pumps
Ground-source heat pumps, also called geothermal systems, use buried tubing to collect heat from the earth. Because underground temperatures stay more stable than outdoor air, these systems can be very efficient.
A closed-loop ground-source system circulates water mixed with antifreeze through buried piping below the frost line.
Ground-source heat pump draws warmth from the ground.
Groundwater Heat Pumps
A groundwater system typically pumps water from one well, transfers its heat to your home, and then returns the water to another well.
These systems can be highly efficient, but installation costs may be significantly higher because of drilling, excavation, and piping requirements.
Key Takeaways
- Heat pumps move heat instead of generating it
- Air-source systems are the most common
- Ground-source and groundwater systems can be more efficient but cost more to install
- Most systems need backup heat during very cold weather
