Central air conditioners are designed to cool the entire house. Most are known as "split systems", meaning the air conditioner's main components are separate from each other. The cooling coil evaporator is mounted inside the home, usually in the furnace plenum; while the other major components (the compressor and condenser coil and fan) are located outdoors.
Split systems use the same ductwork used by the forced warm-air furnace. Heat pumps are like central air conditioners, except that the cycle can be reversed and used for heating during the winter months.