Solar photovoltaic/thermal units which are also known as hybrid photovoltaic/thermal (PV/T or PVT) solar units are systems that could simultaneously produce solar photovoltaic energy and thermal energy. In this paper, a detailed time-dependent thermal model was formulated to calculate and correlate the thermal parameters in a standard PV/T air collector, including solar cell temperature, back surface temperature, and outlet air temperature. The thermal model is coded and implemented in MATLAB software and detailed transient simulation results are obtained. In addition, a 2D model is developed by utilizing COMSOL multiphysics software and the performance of a hybrid photovoltaic-thermal model is also evaluated and the results are validated against experimental data. The thermal simulation results from the two models indicated that the results have good agreement with experimental data.