In this paper, a prototype open loop air-based building integrated photovoltaic thermal BIPV/T system with a single inlet is studied through a comprehensive series of experiments in a full scale solar simulator recently built at Concordia University. A numerical control volume model is developed and validated based on the results from the experiments. Improved designs of a BIPV/T system with multiple inlets and other means of heat transfer enhancement are studied through simulations. Simulation results indicate that the application of two inlets on a BIPV/T collector increases thermal efficiency by about 5% and increases electrical efficiency marginally. An added vertical glazed solar air collector improves the thermal efficiency by about 8%, and the improvement is more significant with wire mesh packing in the collector by an increase of about 10%. The developed model is applied to a BIPV/T roof of an existing solar house with four simulated inlets, and the thermal efficiency is improved by 7%. (C) 2014 Elsevier Ltd. All rights reserved.