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

[SabrinaDella]

You can first turn on the internal circulation to quickly lower or raise the temperature inside the car. Once the temperature stabilizes, appropriately switch to external circulation to exchange air with the outside. Below are the differences between internal and external circulation: 1. Air intake position: The air intake for internal circulation is inside the car, meaning outside air cannot enter, and inside air cannot exit. The air intake for external circulation is located below the front windshield wiper, at the junction of the front windshield and the engine hood, which draws in outside air. 2. Air freshness: Over time, the air in internal circulation becomes stale, with reduced oxygen levels, leading to feelings of heat, fatigue, anxiety, and other symptoms that affect driving safety. External circulation ensures airflow between the inside and outside of the car, preventing excessive carbon dioxide concentration.