Should You Use Internal or External Air Circulation When Running Car AC in Summer?

[KadenLynn]

In summer, it's recommended to first use external air circulation or open the windows for ventilation before switching to internal circulation. Additional relevant information is as follows: 1. External circulation draws air from outside the vehicle through the AC filter and blower, then delivers it into the cabin. 2. Internal circulation closes the external air intake flap. Whether using internal or external circulation, exhaust air inside the vehicle will be discharged through the vents, so there's no need to worry about oxygen levels even when using internal circulation. Additional information: During hot summers, many drivers habitually turn on internal circulation immediately upon entering the vehicle, believing this will cool the cabin faster. However, this is incorrect practice. When interior temperature is higher than outside, this approach actually reduces cooling efficiency.