A numerical model has been created to simulate the performance of a residential-scale building integrated photovoltaic (BiPV) cogeneration system. The investigation examines the combined heat and power system in the context of heat transfer. The (BiPV) cogeneration system will be based on existing BiPV roofing technology with the addition of a modular heat recovery unit that can be used in new or renovation construction schemes. The convection of the air behind the panels, will serve to cool the PV panels while providing a heat source for the residence. This model was created in the Engineering Equation Solver software package (EES), from a series of highly coupled non-linear partial differential equations that are solved iteratively. The model's ability to utilize climatic data to simulate annual performance of the system will be presented along with a comparison to experimental data. A graphical front-end has been added to the model in order to facilitate its use as a predictive tool for building professionals. It will thus become a decision support tool used in identifying areas for implementation of a PV cogen system. (C) 2002 Elsevier Science Ltd. All rights reserved.