the temperature inside a car can rise up to 30oc more than the outside temperature and pose a serious threat for children or pets left in the car, when it is parked outside during summer. the increase in temperature of the car cabin is due to various modes of heat transfer such as conduction, convection and radiation. however, radiation along with the absorption is the main cause of this dramatic rise in temperature. this paper mainly focuses on regulating the internal temperature of the car. a new ventilation system has been designed that employs exhaust fan and blower, temperature sensors and electronic control circuitry to automatically control the temperature inside the car cabin under the constraint that ignition system is off.