Types of Air-Source Heat Pumps

A split-system heat pump heating cycle
A split-system pump heating cycle

You can use a central heat pump to heat and a whole house. Most central heat pumps are split-systems—that is, they each have one coil indoors and one outdoors (see Fig. 1 below). Supply and return ducts connect to a central fan, which is located indoors. The fan, often called an handler or blower, circulates air throughout the house. The fan also usually contains electric resistance coils (some units now have a gas-fired furnace option). The heated or cooled air circulates from the fan to the supply ducts, and openings in the home called supply registers. Return registers and ductwork return the air to the fan to be heated.

Some heat pumps are packaged systems. These usually have both coils and the fan outdoors. Heated or cooled air is delivered to the from ductwork that protrudes through a wall or roof.

Another packaged system is the ductless room heat pump. These pumps will efficiently heat or cool a room or small house with an open floor plan. They are much more common for apartments and motel rooms than homes. They can be installed in a window or through a hole in the wall—wall installations being preferable for appearances sake. Through-the-wall installations, however, sometimes aren't well insulated from inside to outside and can have infiltration problems. When used, mini-split systems can solve these problems.

A split-system heat pump cooling cycle

A split-system heat pump cycle