Building integrated photovoltaics (BIPV) coupled with phase change materials (PCM) (BIPV/PCM) provide opportunities for reducing the photovoltaic (PV) panel temperature to increase the overall efficiency of the BIPV, while also transferring the extracted heat for building energy load management. A comprehensive numerical study is conducted to simulate the effects of different BIPV design parameters namely, BIPV height (H), air gap between BIPV/PCM and wall (delta(Air)) thickness (delta(PCM)), and air mass flow rate ((m) over dot) on the maximum PV panel temperature, the power production by the PV, and the energy extracted by the air. Optimum BIPV/PCM designs are derived from the studies for three different phase change materials, with the goal of maximizing the total energy from photovoltaics (E-PV) and extracted heat (E-air), subject to the constraint of keeping the maximum PV panel temperature to within acceptable values. From the obtained results it is concluded that for the selected range of parameters, the optimum values of delta(PCM), H, delta(Air )and m are, respectively, 0.04 m, 3 m, 0.02 m and 0.18 kg/s for maximizing E-PV and 0 m, 3 m, 0.08 m and 0.091 kg/s for maximizing E-air without any constraints.