The most common type of heating and air conditioning system in the U.S. is a “central split-system,” which has two parts: an outdoor condenser unit and an indoor air handler. The air handler is at a central location in the home and distributes conditioned air through ducts to registers (vents) in the floor or ceiling of each room.
A “ductless mini-split” is also a split system with an outdoor and indoor unit, but there are no ducts. The conditioned air is distributed directly from the indoor unit, which is usually wall-mounted and controlled by a hand-held remote. Most mini-splits are heat pumps, but they are also available as only a cooling air conditioner.
The wall-mount air handler can only service one room, but there are mini-split systems with an outdoor condenser that can serve up to four wall-mounted air handlers. The essential difference between the two types of systems is that a central system distributes air to each room through ducts, while a mini-split delivers refrigerant through small pipes to an air handler in each room it serves.
