The heat from the engine is used to heat the interior of the vehicle while it is running through the fluid that circulates in the cooling system. Fresh air flowing through the heater is heated and is directed to the booth. Heating control is increasingly performed by means of electronic components, by regulating the flow of coolant by means of a throttle valve or by regulating airflow, which is divided into two different streams and mixed together in a proportional throttle. Heating and ventilation system thus ensures a pleasant climate inside the vehicle, appropriate visibility through all windows and an appropriate level of air quality in the cabin, and all this regardless of the weather conditions outside.