The most common residential options in the United States include air-source heat pumps, ducted heat pumps, ductless mini-split heat pumps, geothermal heat pumps, and dual-fuel systems. Other technologies, such as air-to-water and absorption heat pumps, serve more specialized applications.
This guide explains the major types of heat pumps, how they work, their advantages and disadvantages, and the situations in which each type may make sense.
Quick Comparison of Heat Pump Types
| Heat Pump Type | Heat Source | Distribution | Best For |
|---|---|---|---|
| Air-Source Heat Pump | Outdoor air | Ducted or ductless | Most residential applications |
| Ducted Heat Pump | Outdoor air | Existing or new ductwork | Homes with central duct systems |
| Ductless Mini-Split | Outdoor air | Indoor wall or ceiling units | Homes without ductwork and individual zones |
| Geothermal Heat Pump | Ground or water | Air or hydronic distribution | Homes with suitable land and long-term plans |
| Dual-Fuel Heat Pump | Outdoor air plus backup fuel | Usually ducted | Cold climates requiring supplemental heating |
| Air-to-Water Heat Pump | Outdoor air | Water-based system | Hydronic heating applications |
| Absorption Heat Pump | Air, ground, or water depending on system | Specialized | Special applications using thermal energy |
How Heat Pump Types Differ
The easiest way to understand heat pump types is to look at two separate characteristics.
The first is the source and sink used to exchange heat. A system may exchange heat with outdoor air, the ground, or water.
The second is the distribution method. Heat can be delivered through conventional ductwork, ductless indoor units, or hydronic systems.
This means that two systems can both be air-source heat pumps while having very different installation requirements. For example, a central ducted air-source heat pump and a ductless mini-split both use outdoor air but distribute conditioned air differently.
1. Air-Source Heat Pumps
Air-source heat pumps transfer heat between the home and outdoor air. They are among the most common types of residential heat pumps.
During heating operation, the system extracts available heat from outdoor air and transfers it indoors. During cooling operation, the process reverses and heat is moved from the home to the outdoors.
Modern air-source heat pumps are available for a wide range of climates, including systems designed specifically for colder regions. DOE identifies air-source heat pumps as the most common type of heat pump and notes that advances in technology have expanded their usefulness in colder climates. 1
Advantages of Air-Source Heat Pumps
- Can provide both heating and cooling
- Usually less complex to install than geothermal systems
- Available in many capacities
- Available as ducted and ductless systems
- Suitable for many existing homes
- Available in cold-climate models
Potential Disadvantages
- Heating performance changes as outdoor temperature changes
- Outdoor equipment is exposed to weather
- Cold-weather performance varies by model
- May require backup heat in some applications
2. Ducted Air-Source Heat Pumps
A ducted heat pump uses a central indoor air handler or similar indoor equipment and distributes heated or cooled air through ductwork.
This configuration is particularly suitable for homes that already have a central forced-air HVAC system.
ENERGY STAR notes that ducted air-source heat pumps can often connect to existing conventional ductwork, making them a potential replacement for central air conditioners or certain furnace systems. 2
Best For
- Homes with existing ductwork
- Central heating and cooling systems
- Whole-home conditioning
- New construction with planned ductwork
What to Check
Existing ductwork should not automatically be assumed to be suitable. Duct sizing, leakage, insulation, airflow, and condition can affect the performance of the new heat pump.
3. Ductless Mini-Split Heat Pumps
Ductless mini-splits are air-source heat pumps that do not require conventional ductwork.
A typical system consists of an outdoor unit connected to one or more indoor air-handling units. The indoor units can be mounted on walls or ceilings depending on the equipment.
ENERGY STAR identifies ductless mini-split heat pumps as a useful option for homes without existing ductwork, additions, renovations, and spaces where installing or extending ducts would be difficult. 3
Advantages of Mini-Split Heat Pumps
- No conventional ductwork is required
- Can provide zone-based heating and cooling
- Useful for additions and renovations
- Can be used in older homes without central ducts
- Can avoid losses associated with poorly performing ducts
Potential Disadvantages
- Indoor wall-mounted units may be visible
- Multiple rooms may require multiple indoor units
- Indoor units require proper placement
- Some homeowners prefer the appearance of central HVAC registers
4. Single-Zone Mini-Split Heat Pumps
A single-zone mini-split uses one outdoor unit and one indoor unit to condition a particular space or zone.
This can be useful for a bedroom, home office, addition, garage conversion, or other individual area.
A single-zone system can also be useful when the homeowner does not want to replace the entire home’s existing heating system.
5. Multi-Zone Mini-Split Heat Pumps
A multi-zone mini-split connects multiple indoor units to an outdoor heat pump system.
It can provide independent or semi-independent conditioning for multiple areas of a home, depending on the equipment and controls.
Multi-zone systems can be particularly useful when a home has no ductwork and several rooms need heating and cooling.
Potential Advantages
- Multiple rooms can be conditioned
- No conventional ductwork is required
- Individual zones can have separate controls
- Useful for additions and renovations
Potential Limitations
- More indoor units may increase installation complexity
- Indoor-unit placement requires planning
- Outdoor-unit capacity must match the system design
- Not every combination of indoor and outdoor units is possible
6. Geothermal Heat Pumps
Geothermal heat pumps, also called ground-source heat pumps, exchange heat with the ground or a water source rather than directly exchanging heat with outdoor air.
The ground temperature below the surface changes much less than outdoor air temperature. A geothermal system uses an underground heat exchanger to exchange heat with the ground or water.
DOE describes geothermal heat pumps as systems that use relatively stable underground temperatures for heating and cooling. 4
How Geothermal Heat Pumps Work
A geothermal system generally includes a heat pump, an underground heat exchanger, and a distribution system.
During winter, heat is transferred from the ground into the building. During summer, heat is transferred from the building into the ground.
Geothermal systems may use horizontal or vertical ground loops, depending on site conditions and available space.
Advantages of Geothermal Heat Pumps
- Ground temperatures are relatively stable
- Can provide both heating and cooling
- Not directly dependent on outdoor air temperature
- Outdoor equipment exposure is different from air-source systems
- Can have long service lives when properly designed and maintained
Potential Disadvantages
- Higher installation complexity
- Ground-loop installation can be expensive
- Requires suitable site conditions
- May require drilling or excavation
- Not always practical for every property
7. Closed-Loop Geothermal Heat Pumps
Closed-loop geothermal systems circulate heat-transfer fluid through permanently sealed underground piping.
The loops can be installed horizontally or vertically depending on the property and design.
Horizontal systems generally require more land area, while vertical systems can be useful when available land is limited but drilling is practical.
ENERGY STAR recognizes closed-loop configurations among geothermal heat pump system types. 5
8. Open-Loop Geothermal Heat Pumps
Open-loop geothermal systems use groundwater or another suitable water source as part of the heat exchange process.
Because the system interacts with a water source, water availability, quality, discharge requirements, and local regulations need to be evaluated before installation.
Open-loop systems are therefore more site-specific than conventional air-source heat pumps.
9. Dual-Fuel Heat Pumps
A dual-fuel system combines a heat pump with another heating source, commonly a gas furnace.
The heat pump can provide heating during conditions where it is economical or appropriate to do so, while the secondary heating system can provide additional heat when required.
This configuration is sometimes called a hybrid heating system.
Why Choose a Dual-Fuel System?
- Provides two heating sources
- Can reduce reliance on the backup fuel during suitable conditions
- Can provide additional heating capacity during extreme weather
- Can be useful where an existing furnace is still serviceable
The ideal changeover temperature depends on equipment characteristics, climate, fuel prices, electricity prices, and the homeowner’s preferences.
10. Air-to-Water Heat Pumps
Air-to-water heat pumps extract heat from outdoor air and transfer it into water.
Instead of directly delivering heated air through an air handler, the heated water can be used in hydronic distribution systems.
Applications can include radiant floor heating and other water-based heating systems.
DOE identifies air-to-water heat pumps as a distinct type of air-source technology, particularly for systems using water-based distribution. 6
11. Water-Source Heat Pumps
Water-source heat pumps exchange heat with a water source rather than directly with outdoor air.
Depending on the design, the water source can be groundwater, surface water, or a building water loop.
Water-source systems can be highly site-dependent and are more common in specialized residential, commercial, and larger building applications.
12. Absorption Heat Pumps
Absorption heat pumps use a heat source to drive the heat-transfer process rather than relying solely on an electrically driven compressor.
Possible driving heat sources can include natural gas, propane, solar-heated water, or geothermal heat, depending on the system.
Absorption heat pumps are much less common in typical American homes than electric air-source or geothermal systems.
DOE includes absorption heat pumps among the available heat pump technologies. 7
13. Packaged Heat Pumps
A packaged heat pump combines major heating and cooling components into a single outdoor cabinet rather than using a conventional split-system arrangement.
Packaged systems can be useful in homes or buildings where a packaged HVAC configuration is preferred or where installation conditions favor equipment located outside.
Packaged heat pump systems are different from conventional split heat pumps because the major components are integrated into one package.
14. Split-System Heat Pumps
A split-system heat pump separates the indoor and outdoor components.
The outdoor unit generally contains the compressor and outdoor heat exchanger, while the indoor equipment contains the indoor heat exchanger and air distribution components.
Most central residential air-source heat pumps in the United States use some form of split-system design.
15. Variable-Speed Heat Pumps
Variable-speed heat pumps can adjust compressor operation over a range of capacities rather than operating only at one fixed output.
They can provide more gradual capacity adjustment and may improve comfort and efficiency under suitable conditions.
However, variable-speed is a performance and control characteristic, not a completely separate heat-source category. For example, both ducted and ductless air-source heat pumps can use variable-speed compressors.
16. Single-Stage Heat Pumps
Single-stage heat pumps generally operate at one primary compressor capacity.
They are often simpler than more sophisticated variable-capacity systems and may have lower initial equipment costs.
However, they may provide less capacity modulation than two-stage or variable-speed systems.
17. Two-Stage Heat Pumps
Two-stage heat pumps can operate at different capacity levels.
During milder conditions, the system can operate at a lower capacity, while higher capacity can be used when greater heating or cooling output is required.
This can improve comfort and reduce unnecessary high-capacity operation in some applications.
18. Heat Pumps by Heat Source
Another useful way to classify heat pumps is by the source from which they obtain or reject heat.
| Heat Source | Example |
|---|---|
| Outdoor air | Air-source heat pump |
| Ground | Ground-source geothermal heat pump |
| Water | Water-source heat pump |
| Outdoor air to water | Air-to-water heat pump |
19. Heat Pumps by Distribution System
Heat pumps can also be classified according to how they deliver heating and cooling to the home.
| Distribution | Typical Application |
|---|---|
| Ducted air | Central forced-air homes |
| Ductless indoor units | Homes without ducts and individual zones |
| Hydronic water | Radiant floors and water-based heating |
Which Type of Heat Pump Is Best?
There is no single heat pump type that is best for every home.
The right choice depends on the home’s existing HVAC system, ductwork, climate, available land, heating requirements, cooling requirements, budget, and installation conditions.
| If Your Home Has… | Consider… |
|---|---|
| Good existing ductwork | Ducted air-source heat pump |
| No ductwork | Ductless mini-split heat pump |
| Several rooms without ducts | Multi-zone mini-split |
| Very cold winters | Cold-climate air-source heat pump |
| Suitable land and long-term plans | Geothermal heat pump |
| Existing gas furnace | Potential dual-fuel system |
| Radiant heating system | Air-to-water or other hydronic heat pump |
Air-Source vs Geothermal Heat Pumps
The biggest difference is the heat source.
Air-source systems exchange heat with outdoor air, while geothermal systems exchange heat with the ground or water.
Geothermal systems can take advantage of relatively stable underground temperatures, but they generally require more extensive site work and installation. DOE notes that geothermal systems typically have higher installation costs than air-source systems but can have lower operating costs. 8
Ducted vs Ductless Heat Pumps
Ducted heat pumps use a home’s duct system to distribute conditioned air. Ductless mini-splits use indoor units connected directly to an outdoor heat pump.
If a home already has suitable ductwork, a ducted system can be a straightforward option. If there is no ductwork, a ductless system may avoid the cost and disruption of installing a complete duct network.
Mini-Split vs Central Heat Pump
A mini-split is generally better suited to homes or areas without ductwork, while a central ducted heat pump is often convenient for homes that already have a suitable forced-air duct system.
Neither configuration is automatically better. The home’s layout and existing HVAC infrastructure should determine the choice.
Cold-Climate Heat Pumps
Cold-climate heat pumps are designed to maintain useful heating performance at lower outdoor temperatures.
ENERGY STAR’s current cold-climate criteria include a COP requirement at 5°F and a requirement for the system to retain a specified percentage of heating capacity at 5°F compared with its rated capacity at 47°F. 9
If you live in a cold region, do not compare heat pumps solely using their seasonal efficiency ratings. Look at actual low-temperature heating capacity and performance.
How to Choose the Right Heat Pump Type
Use the following process before choosing equipment:
- Determine whether your home has suitable ductwork.
- Identify your climate and winter design temperatures.
- Determine your heating and cooling requirements.
- Decide whether you want whole-home or zoned conditioning.
- Consider whether geothermal installation is practical on your property.
- Evaluate your existing heating equipment.
- Determine whether backup heat is required.
- Compare equipment and installation costs.
- Have the system properly sized.
- Choose an experienced installer.
Common Mistakes When Choosing a Heat Pump Type
Choosing Based Only on Price
The cheapest system may not be the best fit for your home or climate.
Ignoring Existing Ductwork
A central heat pump depends on the condition and design of the duct system.
Assuming All Mini-Splits Are the Same
Mini-splits differ in capacity, low-temperature performance, efficiency, controls, indoor-unit options, and zoning capability.
Ignoring Property Conditions for Geothermal
Ground-source systems require appropriate site conditions and a properly designed ground loop.
Choosing a Heat Pump Without Considering Backup Heat
In colder climates, determine how the system will handle outdoor temperatures below its preferred operating range.
Frequently Asked Questions
What are the main types of residential heat pumps?
The main residential categories include air-source, ducted air-source, ductless mini-split, geothermal, and dual-fuel heat pump systems. Other technologies include air-to-water and absorption heat pumps.
What is the most common type of heat pump?
Air-source heat pumps are among the most common residential heat pump systems. They transfer heat between the home and outdoor air. 10
Are mini-splits heat pumps?
Yes. A ductless mini-split can be a heat pump when it provides both heating and cooling through a reversible refrigeration cycle.
Are geothermal and ground-source heat pumps the same?
In residential applications, geothermal heat pumps are commonly referred to as ground-source heat pumps. They exchange heat with the ground or, in some systems, a water source.
Which heat pump is best for a house without ducts?
A ductless mini-split is often an appropriate option because it does not require conventional ductwork.
Which heat pump is best for a house with ducts?
A ducted air-source heat pump is often the most straightforward option when existing ductwork is suitable.
Are geothermal heat pumps worth it?
They can make sense for homeowners who have suitable property conditions and plan to remain in the home long enough to benefit from the system’s long-term operating characteristics. Installation costs can be substantially higher than for air-source systems.
Do all heat pumps work in cold weather?
Heat pumps vary significantly in cold-weather performance. If you live in a cold climate, look for a system specifically designed and tested for low-temperature operation.
Final Verdict
The best heat pump type depends on the characteristics of the home rather than simply the brand or efficiency rating.
Ducted air-source heat pumps are often a logical choice for homes with suitable central ductwork. Ductless mini-splits are useful where ducts are unavailable or zoning is important. Geothermal heat pumps can be attractive for properties where ground-loop installation is practical and long-term performance is a priority. Dual-fuel systems can provide an additional heating source in suitable homes and climates.
Before purchasing equipment, consider the home’s distribution system, climate, heating and cooling loads, installation conditions, and total cost. The equipment should then be properly sized and installed by a qualified professional.
Related Heat Pump Type Articles
- Best Air-Source Heat Pumps
- Best Ducted Heat Pumps
- Best Ductless Heat Pumps
- Best Mini-Split Heat Pumps
- Best Geothermal Heat Pumps
- Best Cold-Climate Heat Pumps
- Best Dual-Fuel Heat Pumps
- Air-Source vs Geothermal Heat Pump
- Ducted vs Ductless Heat Pump
- Mini-Split vs Central Heat Pump
- Air-to-Water Heat Pumps
- Closed-Loop vs Open-Loop Geothermal Heat Pumps
- Single-Stage vs Variable-Speed Heat Pumps
- Packaged vs Split-System Heat Pumps
- What Is a Dual-Fuel Heat Pump?
About the Author
ManBearPig is a part-man, part-bear, part-pig creature and a full-time expert on global warming—mostly because he has personally experienced the consequences of being extremely, extremely, super cereal.
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