Should You Use External or Internal Air Circulation for Defogging on Rainy Days?

[RoseLee]

For defogging on rainy days, use external air circulation. If the rain isn't too heavy, you can also crack open a window slightly for faster defogging. More related information is as follows: 1. Car air conditioning systems have both internal and external air circulation modes, and many drivers don't use them correctly. For long-distance or highway driving where opening windows isn't convenient, it's recommended to use external circulation. If driving in congested urban traffic, internal circulation is advised. 2. Car air conditioning systems have cabin air filters that need regular replacement. Typically, these filters should be changed every 10,000 kilometers. The cabin air filter purifies incoming air - failing to replace it regularly will reduce air conditioning efficiency and may affect passengers' health.