A building control system includes a central coordinator and one or more discrete air conditioner controllers configured to communicate with one or more discrete air conditioner units servicing the building. In some instances, a discrete air conditioner controller may be configured to transition between a sleep mode and an active mode. The discrete air conditioner controller may also be configured to transmit over a mesh network in the active mode and to not transmit over the mesh network in the sleep mode. The discrete air conditioner controller may be configured to transition between the sleep mode and the active mode according to a schedule dictated by the central coordinator. Alternatively, or in addition, the discrete air conditioner controller may be configured to transition between the sleep and active modes in accordance with a beacon signal received from the central coordinator.