The smart building and plug-in hybrid electric vehicle (PHEV) are two promising technologies. The integration of these two emerging technologies holds great promises in improving the power supply reliability and the flexibility of building energy and comfort management. The overall control goal of the smart building is to maximize the customer comfort with minimum power consumption. In this study, multi-agent technology coupled with particle swarm optimization (PSO) is proposed to address the control challenge. The proper aggregation of a number of PHEVs turns out to be able to provide both capacity and energy to make the building more economical and more reliable by impacting the building energy flow. Case studies and simulation results are presented and discussed in the paper. (C) 2011 Elsevier B.V. All rights reserved.