The present paper describes Solar Roof Panels and their applications to car ventilation. The Solar Roof Panels contain hydrogenated amorphous silicon solar cells. The process used for the solar cell fabrication is basically the same as conventional processes; hydrogenated amorphous silicon layers are deposited by plasma enhanced chemical vapor deposition (CVD). In our process, however, the hydrogenated amorphous silicon solar cells are directly fabricated onto the compound curved surface of the outer glass of the sun roof. Then they are hermetically sealed by laminating with the inner glass.We applied the Solar Roof Panels to power supply unit for the car ventilation during parking. The Solar Roof Panels were mounted onto the roof of the cars as a sun roof. Then we monitored the temperature decrease, while the ventilator was driven by the Solar Roof Panels. Also the cooling effect of air conditioning after ventilation during parking was estimated.In the case of summer season, there was 13 degrees difference between with and without ventilation. Moreover, the subtracted heat with air conditioning system was decreased 17% with ventilation during parking. From these results, it can be concluded that the driver would feel more comfortable, when he takes his seat after parking under sunshine.