Abstract: A central system wherein conditioned or heated air is supplied to a plurality of rooms to be air-conditioned through a common duct, the system comprising: means for generating conditioned air or heated air and forcibly supplying the air to a plurality of rooms; a vent control mechanism, corresponding to a vent in each room, for controlling a flow of the conditioned air from the common duct into corresponding room; a room remote controller, provided in each room, including a command signal to control the operation of the vent control.