The amount of heat extracted from bottom surface of PV module of hybrid solar water system is strongly influenced by the air gap between the bottom surface of module and top surface of heat exchanger. The heat transfer analysis between these two surfaces is studied in this research work. For this, outside heat transfer coefficient of stagnant air was calculated & found to be 50 W/m20k. By using desired correlation, air gap between these surfaces was found to be 0.53 mm. For this air gap with solar radiation of 918 W/m2 and mass flow rate at 0.035 kg/sec, this system generated a combined PV/T energy with efficiency of 53.7 % with maximum PV efficiency of 11.7 %. These results showed that heat transfer from these surfaces had been strongly influenced by the air gap or air resistance.