A method for controlling an air conditioner system may include receiving, by one of an outdoor unit and a plurality of indoor units in a group, a command; transmitting, by the outdoor unit, a channel scan command to the plurality of indoor units; performing a channel scan by each of the outdoor unit and the plurality of indoor units; transmitting, by the plurality of indoor units, channel scan results to the outdoor unit; determining, by the outdoor unit, a channel to be used among a plurality of pre-set channels of a particular group based on a result of the channel scan performed by the outdoor unit and the channel scan results received from the plurality of indoor units; and outputting, by the outdoor unit, information on the channel to the plurality of indoor units. According to this method, an optimal wireless communication channel may be set.