A ducted unit, known as a ducted air conditioner, is a form of central air conditioning system that is usually used in commercial buildings, office buildings, hotels, and other large venues. It distributes warm and cool air to various rooms or areas through a duct system. A ducted unit consists of an indoor unit, which is usually installed in a suspended ceiling or in a specialised equipment room, and an outdoor unit, which is placed on the outside of the building.