Abstract Night cooling strategies are gaining popularity with the raise in profile of Green Buildings and Sustainable rating systems. The use of night ventilation to exploit lower diurnal temperatures to pre-cool the building structure in preparation for the following day's gains is well known; however, the role which the facade has to contribute to night ventilation is not fully understood. Researchers are familiar with economiser cycles operation for central air conditioning systems and the ability of these to operate in night ventilation mode with simple modifications to the control strategy requires validation. Simulations were carried out for a typical office building in Adelaide to demonstrate that a traditional economiser cycle operating 24 h each day under thermostatic control delivers energy savings. A number of facade structures were considered and the effect of varying the location of the thermal mass within the structure was investigated. The paper gives details on the model used for the simulations and discusses the results obtained. It was found that increasing the mass on the inside of the facade is preferred over the external for the warm marine climate zone of Adelaide, South Australia.