Ductless, mini-split-system heat pumps (mini splits), as their name implies, do not have ducts. Therefore, they make good retrofit add-ons to houses or buildings with "non-ducted" heating systems, such as hydronic (hot water heat), radiant panels, and space heaters (wood, kerosene, propane). They can also be a good choice for room additions, where extending or installing distribution ductwork is not feasible.
How Ductless, Mini-Split Heat Pumps Work
Like standard air-source heat pumps, mini splits have two main components: an outdoor compressor/condenser, and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units. Some models have multiple air handling units that all connect to one outdoor unit. Each air handling unit is assigned to a different zone or room, which is controlled by its own thermostat.
Visit the Energy Saver website for more information about the advantages and disadvantages of ductless, mini-split heat pumps in homes.