Five energy management control (EMC) functions such as outside air (OA) economizer cycle, programmed start and stop lead time, load reset and occupied time adaptive control strategy are developed and evaluated using a variable air volume heating, ventilating and air conditioning, VAV-HVAC, system level dynamic model as a simulation platform. A real time system embedded with the above EMC functions is presented. The simulation results manifest that energy savings of 17% can be achieved when the system is operated with the EMC functions and optimal set points compared with the system without such functions. These results do point out that the optimal set point strategy is very useful in achieving energy efficient operation of HVAC systems. (c) 2005 Elsevier Ltd. All rights reserved.