The Duct air conditioning system is used in office spaces, shopping centers and other large areas. The system consists of an internal unit where the air is cooled or heated (as the case may be), then sent by fans through a piping system to the desired areas. Duct air conditioners are used to achieve the desired climate on large surfaces. The air from the interior space is taken by the internal unit, heated or cooled and then distributed evenly through a system of grids and diffusers mounted in the ceiling connected to the duct. The duct type air conditioning unit is also mounted in the ceiling, it is not visible.