Is it better to use internal or external air circulation when driving in the rain?

[OAngela]

It is better to use external air circulation when driving in the rain. On rainy days, the cold weather causes fog to form on both side windows, obstructing the driver's vision. Therefore, it is best to first use the external air circulation mode and adjust the airflow direction towards the windshield. Using external circulation helps expel the moisture exhaled by passengers from the vehicle, while the outside cold air is less prone to condensation. Methods for using internal circulation: 1. When the outside air quality is poor or heavily polluted, such as on dusty roads, in congested traffic, or near chemical plants with foul odors or unusual smells; use internal circulation to prevent bad outside air from entering the vehicle. 2. In summer, to quickly cool down the interior with air conditioning, internal circulation can be used. 3. In winter, using internal circulation can help keep the interior warmer. Methods for using external circulation: 1. When internal circulation has been used for an extended period and opening the windows is inconvenient, periodically switch to external circulation to allow fresh air into the vehicle. 2. When there are many passengers in the vehicle, using external circulation can maintain fresh air and prevent excessive humidity inside that could lead to window fogging. Both internal and external circulation methods can enhance comfort to some extent. Choose the appropriate mode based on the situation. Sometimes, combining the use of window controls with internal and external circulation can also reduce the burden on the air conditioning system.