An integrated air conditioning system includes a ventilation device comprising a first temperature sensor, a first humidity sensor, and a heat exchanger installed on the inlet flow path. An indoor unit configured to discharge heat-exchanged air into an indoor space. An outdoor unit configured to supply a refrigerant to the ventilation device and the indoor unit. A controller connected to the ventilation device, the indoor unit, and the outdoor unit. The controller configured to obtain an indoor temperature from the first temperature or the second temperature sensor. The controller configured to obtain indoor humidity from the first humidity sensor or the second humidity sensor and configured to control at least one of the ventilation device and the indoor unit based on the indoor temperature and the indoor humidity.