A typical commercial building was selected for a detailed study of energy use by mechanical ventilation and air-conditioning (MVAC) systems. Data from preliminary building energy auditing were analyzed and compared with the energy use of other similar buildings. Correlation relationships between the building envelope heat gain and the electrical energy use for MVAC system with key parameters were derived with approaches similar to the Princeton Scorekeeping Method (PRISM). Further, the energy simulation program TRACE 600 was used to justify the results. A total of 20 energy-saving measures were investigated for possible use in local commercial buildings. The results provided are useful for engineers in designing energy-efficient commercial buildings or generating new design concepts for better MVAC systems. (c) 2006 Elsevier Ltd. All rights reserved.