This paper introduces a transmission optimization algorithm for wireless transmissions between smart load controllers and a corresponding gateway in wireless personal area networks, where smart load controllers connect several electrical appliances through their corresponding load interfaces, measure the power consumption from each electrical appliance connected to the load controller, and control on/off switching through its load interface. The aim of this paper is to reduce the traffic load of power consumption data in electrical appliances used in the building area network and the smart grid network. The proposed algorithm allows the smart load controller to efficiently reduce traffic load even if watt-hours calculated in the smart load controllers are the same as the watt-hours in the gateway and the errors of the present values of power consumption interpreted in the gateway fall under the typical tolerance allowed in the specifications of manufacturers of watt-hour meters used in the electrical power industry.