Homes with existing forced air systems can use the existing ductwork with their heat pumps. An air handler is included in the installed heat pumps systems. Since heat pump systems require 20-30% higher air flow rates than conventional forced air furnaces, it is important to have the installer inspect the existing ductwork. For more information, see Air flow.
Mini-split or multi-split heat pumps (MSHP) often work without ducts. The indoor heat pump units release conditioned air directly into the room. Mini-splits are ideal for heating a single open room, while multi-splits have multiple heat exchanger units in multiple locates, each releasing conditioned air directly into the room.
Radiator and in-floor systems
Homes that use radiators or in-floor systems with pumped water can also make the switch to heat pumps. Air to water heat pumps are designed to heat or cool the water used in these hydronic systems.