The effects of condensers installed in the stacked air-conditioning plant rooms of a high-rise apartment building were studied numerically. The performance of the condensers was evaluated using the coefficient of performance (COP) and condenser group performance indicator (CGPI) parameters. The effects of wind direction, wind velocity, and the arrangement and location of the condensers were investigated. The performance of condensers above the 30th floor was seriously degraded due to the stacking effects. The heat dissipation performance of the condensers in the higher floors dropped significantly when the frontal wind was greater than 4 m/s and the side wind was greater than 8 m/s. The condenser should be arranged in such a manner that the fan of the condenser faces the outside of the building to exhaust the hot air directly to the outside. To prevent the hot air from reentering the air-conditioning plant room and to allow fresh air to enter instead, the condenser considered in this study must be located at the lower left corner of the air-conditioning plant room. (C) 2004 Elsevier Ltd. All rights reserved.