Energy saving in air conditioners is a primary concern in building projects, since air conditioners consume a large proportion of the energy in building service equipment. Research on energy saving in air conditioners focuses mostly on the chiller system and the associated control strategies. For air conditioners in buildings, the thermal control strategy to adjust the temperature set point is very easy to implement and very effective to save energy. In this paper an energy consumption calculation model of a data center in South Africa is presented to estimate the energy consumption of air conditioners at different temperature set points. In order to illustrate the accuracy of this model, measured energy consumption from a data center is compared with the calculated energy consumption from this model, and the coefficient of variation of the root mean square error between the estimated data and measured test data is 11.5%. (C) 2013 Elsevier B.V. All rights reserved.