Should You Use Internal or External Air Circulation When Turning on the Car Heater in Winter?

[BradleyMarie]

Whether to use internal or external air circulation when turning on the car heater in winter depends on the specific situation: 1. When driving on urban roads, internal circulation can be used; 2. When driving on highways or long-distance routes, it is recommended to turn on external circulation; 3. Do not use external circulation when stuck in traffic. The differences between internal and external air circulation in cars are: 1. The method of air circulation is different: external circulation draws air from outside the car; internal circulation draws air from inside the car. 2. The symbols on the car air conditioning panel are different: the symbol for external circulation is from outside to inside; the indicator for internal circulation is an arrow pointing inward. 3. The functions are different: external circulation draws fresh air from outside the car to maintain air quality inside the car; internal circulation effectively prevents external dust and harmful gases from entering the car, improving the cooling and heating effects of the air conditioning.