A ductless heat pump, also known as a mini-split, provides heating and cooling without requiring ductwork. These units provide flexibility and are a great solution for bonus rooms and expansions, hot and cold spots in the home, and homes without existing ductwork. If enough are installed, they can fully replace an existing HVAC system, though more often they’re installed to augment existing systems.

Ductless heat pumps are often installed in a one-to-one setup, with a single outdoor unit connected to a single indoor, or head, unit. The head units are typically mounted on the wall, but can also be floor-mounted, in-wall units, or in-ceiling cassettes with smaller ducts leading to multiple rooms.

Most systems can also be installed in multi-split setups as well, with a single outdoor unit supplying multiple indoor units.

A ducted heat pump functions like a ductless heat pump, but the outdoor unit replaces the traditional air conditioner outside and connects to the indoor ductwork through the air handler. This air hander unit can be a fully-electric system with an electric furnace as back-up, or a hybrid system with a fossil fuel furnace as back-up – this second type is also called a dual-fuel system and is described further below.

Ducted heat pumps typically have a large outdoor unit and are meant to offset a sizable portion of the heating and cooling load of the home. The size of the heat pump installed is often limited by the size of the existing ductwork in the home, however – a limitation not shared by its ductless counterparts.

In some cases, heat pumps provide all a home’s heating and cooling with electricity, but some homeowners have opted for a dual-fuel heat pump. This is not a different type of heat pump, but a mix of heating equipment using different fuel sources, more specifically a ducted heat pump—which is electric—being paired with a gas or propane furnace. In these configurations, the heat pump provides the primary heating, and the furnace serves as a back-up. A dual-fuel heat-pump could be a good investment for your home if your air conditioning system needs replacement or is inefficient, but your furnace is still in working order. This allows you to take advantage of cost savings from both technologies: efficient heating from your heat pump in mild temperatures as well as cheaper natural gas from your furnace on the coldest days of the year.

Finally, there are cold climate heat pumps. Their name refers to their ability to operate more efficiently at low outdoor temperatures than standard air source heat pumps. Cold climate heat pumps have a variable speed inverter-drive compressor allowing the unit to continue providing efficient heat in freezing temperatures. Both ducted and ductless heat pumps can be cold climate heat pumps.

Also known as ground source heat pumps, these systems use the relatively constant temperature of the ground to heat and cool your home. Instead of using the air around the outdoor unit, geothermal heat pumps use liquid-filled pipes buried in the ground to utilize heat stored in the Earth. Just like air source heat pumps, these come in various configurations including horizontal or vertical, closed-loop or open-loop, pond/lake, and hybrid systems.

Due to higher installation and material costs, geothermal heat pumps cost more than other heat pumps. However, these are a smart investment as they can last longer than 50 years.

Heat pumps are a fascinating spectrum of technology with lots of future potential. Other heat pump types you may hear about include air-to-water, water source, and gas absorption heat pumps. See the research section below for more information on these emerging technologies.

Though heat pumps are new to Wisconsin, they aren’t a new technology. Focus on Energy has supported several research projects to explore the feasibility and implications of heat pumps in the state. See what we’ve learned.

Single-Family & Multifamily Air Source Heat Pumps (ASHP)

Check out these leading national organizations for more heat pump information.