Power management system and control method thereof

PURPOSE: An energy management system and a control method thereof are provided to reduce traffic load between the energy management system and each display device. CONSTITUTION: An energy management system includes communication units (230,240), a storage unit (250) and a control unit (260). The communication unit communicates with a plurality of display devices. The storage unit stores state change information of a plurality of home appliances. The control unit changes energy level of the plurality of home appliances, and receives state change information according to the energy level change of the plurality of home appliances. The control unit stores the received plural state change information in the storage unit, and controls the communication unit to transmit the state change information of the plurality of home appliances stored in the storage unit to a plurality of display devices with bundles. [Reference numerals] (210) Input unit; (220) Display unit; (230) First communication unit; (240) Second communication unit; (250) Storage unit; (260) Control unit; (AA,BB,CC) Home appliance; (DD,EE,FF) Display device