An air conditioning system that controls an air conditioner (1) comprising a compressor (21) comprises a control unit that controls the air conditioner (1). The control unit controls the air conditioner (1) by switching between normal control and energy saving control in which the amount of power consumed is reduced in comparison to normal control. During normal control, the rotational speed of the compressor (21) is controlled according to the difference between the room temperature and the set temperature. During energy saving control, the set temperature is changed in stages in a state where the set temperature is correlated with the rotational speed of the compressor (21) that is the minimum amount of consumed power that corresponds to the set temperature.
