Modelling and simulation of energy consumption in Information Technology (IT) building on the Rockhampton campus of Central Queensland University, Australia is presented. Design Builder, commercially available software, was used for the prediction of energy consumption. All the possible sources and uses of energy in building were accounted in the modelling and simulation. The operation of the Heating, Ventilation and Air Conditioning (HVAC) system and the lighting energy consumption of the whole building has been studied in detailed. The factors that affect building energy performance and thermal comforts of the occupants during summer and winter have been identified. Further studies are being carried out to evaluate whole building annual thermal performance and retrofit decision making.