Water-cooled air-conditioning systems (WACS) are widely used in the commercial sector for energy efficiency, but not in the domestic sector. It has been found that there are no mathematical models and energy simulation programs to enable detailed investigation and evaluation into the energy performance of water-cooled air-conditioners. To improve the applicability of water-cooled air-conditioners in the domestic sector, the development of a prediction model for energy performance analysis is needed. This paper addresses the development of an empirical model for predicting the operational performance and energy consumption for the use of water-cooled air-conditioners. The model consists of four sub-models which has taken into account the energy consumption of the condenser water system. A prototype WACS was set up and tested in an environmental chamber to validate the resultant model. The overall COP of the WACS was found to be greater than 3 at 90% rated capacity. The predictions from the model compared well with-the experimental results, with RMS error within 11%. (C) 2008 Elsevier B.V. All rights reserved.