The SG (smart grid) is a modernized and a future-oriented electric grid that deals with the whole energy chain, from generation to consumer. Among the SG applications, DR (demand response) is an important control mechanism to manage the electricity consumption of the customer in response to supply conditions. In buildings, DR is managed through installed communication networks which support DR applications. BACnet is an international standard communication protocol for building automation and control systems. BACnet uses ZigBee as a wireless communication protocol. Both BACnet and ZigBee have their own DR applications. In this study, we developed a BACnet-ZigBee gateway that maps the DR application of BACnet to that of ZigBee and vice versa. In addition, we developed an experimental facility to demonstrate how the BACnet-ZigBee gateway can be implemented for DR applications in buildings. We also measured the communication delay to verify that the BZ-GW (BACnet-ZigBee smart grid gateway) developed here satisfies the requirements of real-time DR service in buildings. (C) 2013 Elsevier Ltd. All rights reserved.