Dimensional analysis was applied to the design of a small-scale model building. The model was used to simulate the thermal response of a building and two-stage heating, ventilation, and airconditioning (HVAC) system, operating under automatic control. Temperature variation, in the course of a series of heating and cooling cycles, was monitored by computer. The observed thermal response of the model was found to be fairly realistic. The modelling technique is currently being refined, and will include the effects of solar gains, humidity, and air movement. The method should offer an inexpensive and reliable means for evaluating the impact of new building materials and technologies on the built environment.