A method of controlling a central air conditioning system includes, when a first air volume determined based on humidity in each of a plurality of rooms is less than a second air volume determined based on air quality in the room, causing a conveyor to convey air with a second air volume determined for a first room to the first room and convey air with a third air volume to a second room other than the first room, the third air volume being obtained by correcting the first air volume determined for the second room.