AIR CONDITIONING SYSTEM

When the air conditioner implements the temperature controlling operation, the ventilator performs ventilation in a normal ventilation mode where a ventilation amount is set at a certain ventilation amount or more. When the air conditioner implements the operation not intended for temperature control, the ventilator performs ventilation in a ventilation suppressed mode where the number of rotations of an exhaust fan is made greater than that of an air supply fan to place indoor space in a negative pressure and ventilation is performed at an amount smaller than the certain ventilation amount or ventilation is stopped. In the ventilation suppressed mode, a ventilation amount is set to be smaller in response to a greater heating load that is increased by ventilation performed during the operation not intended for temperature control.