PVT technology presents many attractive features for a wide application in the building sector since it is able to produce electricity and thermal energy at the same time with better overall performances and reduced surfaces in comparison with the two separated solar technologies. However the effectiveness of the PVT modules is most evident when they are integrated in complex systems, capable of fully exploiting their multi-functionality (e.g. heat pump coupling, multi-storage interconnection, etc.). For that reason, the research work presents a mathematical model for energy simulation of PVT systems, which takes in account all factors and parameters involved in the energy performance of an uncovered hybrid collector; the model can be easily implemented in any performance calculation tool in order to carry out technical-economic assessment of PVT systems. The experimental calibration and validation of the proposed model was performed in outdoor conditions on a commercial PVT product, at the Test Facility of the Politecnico di Milano University, and finally the model was ran supposing the application in three different locations. The validation of the developed simulation model shows a good agreement with monitored data also if a mismatch occurred due to an assembling defect of the tested commercial PVT component. (C) 2016 Elsevier Ltd. All rights reserved.