In order that proposed energy conservation methods may be evaluated and compared,theoretical models of buildings and systems should be available to the designer.The purpose of the study reported in this paper was the development of computersimulation methods for predicting, (1) heating and cooling load profiles usingweather, structural and architectural data as input; (2) energy consumption ofthe system with the load profile as the input. Detailed field measurements ona test building were compared with the simulated results. Simulations werebased on algorithms available in the open literature and manufacturers' datawere obtainable.