Central air conditioners, also known more simply as “central air,” are used for larger homes or buildings as residential air conditioners. They have a cooling compressor located outside of the home. This is the part of the system that cools the air. In the cooling compressor, a refrigerant-filled coil cools the air, which is then blown by a fan throughout the home through ducts.
Central air conditioners circulate use supply and return ducts to push cool air through a building while warm air is carried back through the return system and pushed out of the house through an exhaust system. The advantage of this system is that the only noisy part is outside of the home, but they are also more expensive than portable or window units, and installation can be expensive or complicated, especially for an older building.