Should the car's air conditioning be set to recirculation mode in winter?

[DeEmily]

Whether to use recirculation mode for car air conditioning in winter depends on the situation. When using the heater in winter, it is recommended to use recirculation mode for short trips and fresh air mode for long trips. The relevant introduction of the circulation system is as follows: Recirculation system: The air exchange channel between inside and outside the car is closed. When the fan is off, the air flow inside the car does not circulate. When the fan is on, the inhaled air flow only comes from inside the car, forming an internal air flow circulation. Fresh air system: In fresh air mode, the fan draws air from outside the car into the car. The air blown by the fan comes from outside the car. Even if the fan is not turned on, there is still air flow entering the car while driving, replenishing fresh air inside the car.