This paper presents a novel framework for designing and simulating the decentralized control of Building Management Systems (BMSs) based on the concept of virtual smart meters. The proposed approach uses simulation in realtime to allow building managers and users to have a thorough perception of the power consumption, which establishes the basis of Demand Side Management for energy-efficient buildings. It will be demonstrated that predefined power usage scenarios can be simulated in the closed-loop model and the results can be intuitively analyzed. More importantly, the decentralized control logics of the BMS subsystems can be developed independently from the deployment configurations