
External circulation does not require turning on the fan speed. Definition of external circulation: External circulation refers to the process of drawing air from outside the vehicle, cooling or heating it through the blower, with the primary feature being the ability to replenish fresh air from outside and maintain air flow. Usage of external circulation: Turn on the external circulation of the air conditioning system and reduce or turn off the fan speed. This allows for air circulation inside the vehicle while maintaining a comfortable temperature, resulting in a more pleasant experience. During long drives on highways, a sense of suffocation may develop due to increased carbon dioxide concentration inside the vehicle. Turning on the external circulation ensures timely replenishment of fresh air into the cabin.

I've been driving for over 20 years. The recirculation button is just a fresh air intake, while the fan speed knob controls the airflow volume. They operate independently, so you can use recirculation without turning on the fan. During long trips, I often turn on recirculation without activating the fan—like on sunny highways—just pressing the recirculation button allows natural airflow without forced ventilation, as if the windows were open. This saves fuel and is eco-friendly, especially during spring pollen season, avoiding dust stirred up by the fan. Try it—recirculation without fan speed feels great, but if the cabin gets stuffy or smelly, a low fan speed helps circulate air faster. Just remember, in winter, recirculation might cause fogging, requiring slight fan speed for defogging. Overall, adjusting them separately offers much more flexibility.

From the perspective of commuting by car, office workers are all familiar with urban air pollution. Turning on the external circulation mode introduces fresh air, but whether to turn on the fan speed depends on the situation. As someone who drives every day, I've found that turning on external circulation doesn't necessarily require the fan speed to save energy. For example, when the morning air is fresh, air can still circulate without the fan speed. However, during peak traffic jams with more exhaust fumes, setting the fan to medium speed helps quickly refresh the air and prevent fatigue driving. For environmental reasons, I recommend using external circulation with low fan speed, which ensures ventilation while reducing fuel consumption. A safety tip to emphasize: on rainy days, using external circulation without the fan speed can easily cause fogging, affecting visibility, so turning on some fan speed for dehumidification is crucial. Also, regular cleaning of the air conditioning system ensures cleaner use of external circulation.

New Driver Experience: As a novice driver, I've used the air recirculation button and fan speed control, which are two separate switches. When the air recirculation is on, I can choose not to adjust the fan speed. For example, in summer, I can have cool air blowing in without turning on the fan, which feels natural and comfortable. However, it's recommended to use a low fan speed for better ventilation. The operation is quite simple. I've tried using air recirculation in the city without fan speed, and the odor removal was slow, but turning on some fan speed made it much faster. Remember to check the air filter to avoid blockages that could affect performance.

Safety-first perspective: I prioritize the driving environment, using the external air circulation to introduce fresh air and prevent drowsiness, but adjust the fan speed based on road conditions. On long-distance drives, it's beneficial to turn on external air circulation with some fan speed for better air exchange, especially on highways during windy days to avoid noise. In industrial areas with poor air quality, increase the fan speed to accelerate filtration and prevent passenger discomfort. It's recommended to alternate between internal and external circulation for higher efficiency.

Chatting among car enthusiasts: From my modification experience, the air conditioning system's damper controls the opening and closing of the external circulation, while the fan controls the wind speed. The external circulation can intake air without turning on the fan, but it doesn't have fan output air volume. For example, during spring outings, you can turn on the external circulation and turn off the fan speed to enjoy natural wind; turning on a bit of fan speed increases air volume for quick defogging. The importance of air conditioning cleaning is worth mentioning, as regular prevents bacterial buildup.


