As the number of buildings that use the transparent permeation materials as the outer wall increased resulting in coming amount of light rays, the increase in the cooling load and the amount of radiant heat may cause discomfort to the residents. In order to reduce such effect, the installation effects of roof BIPV were to be analyzed. The temperature in the room where sun shade BIPV system was not installed and the temperature in the room where sun shade BIPV system was installed were measured and compared, and the effect of reducing the cooling load by the incoming light rays in the two rooms was compared and analyzed. The sample space of the third floor of the engineering and science building of S university in which sun shade BIPV system is installed has two rooms of the same condition, and for five sunny days selected in August, we measured the air temperature and the temperature of the fittings by closing the windows to minimize the movement of air without operating the coolers. In the room where sun shade BIPV system was installed, the maximum cooling load by the incoming light rays was measured as 745.46kcal/h, and it can be attributed as the effect of reducing the cooling load by the incoming rays of the room with sun shade BIPV system installed in it. Even though the effect of cooling load reduction is not that great in a room, the total reduction in cooling room for 32 rooms where sun shade BIPV system is installed was estimated to be 23,854.72kcal/h which will reduce the investment cost significantly due to the reduction in cooling load when initially designing the building and attain the maximum reduction effect of 27.725kW in energy