This paper presents a first attempt at obtaining a reusable and scalable model of buildings. To this end, a university building is first modeled using EnergyPlus, an energy simulation software. The EnergyPlus model is then validated using measured temperatures in the university building. In a second part, the EnergyPlus model is used to generate informative input/output data to perform system identification techniques: a black-box model of the building is obtained. Using simulation experiments, it is showed that the structure of the black-box model can be used to model the building at different scales: a thermal zone, a floor or the whole building. (C) 2014 Elsevier B.V. All rights reserved.