How Long Can the Internal Circulation Be Kept On?

[StGiselle]

Do not keep the internal circulation on for too long. The internal circulation mode closes the airflow channels between the inside and outside of the vehicle. Without the fan, there is no airflow circulation, and when the fan is on, the airflow drawn in comes only from inside the car, creating an internal airflow cycle. The purpose is to prevent harmful external substances from entering the vehicle and to maintain warmth. However, prolonged use can cause a feeling of stuffiness. Additional Information: Usage of Internal and External Circulation: 1. External Circulation: If driving at high speeds for a long time without ventilation, the air inside the car becomes stale. In summer, you can open the windows for ventilation, but in autumn, opening windows at high speeds can be very cold. In such cases, turn on the external circulation to ensure timely air exchange, maintaining warmth while keeping the air fresh. 2. Internal Circulation: It can block external air, but prolonged use during long drives can lead to oxygen deprivation inside the car, especially when there are many passengers. Oxygen deprivation can cause dizziness and reduced concentration for the driver. Therefore, if the temperature inside the car is comfortable, it is recommended to turn off the internal circulation and switch to external circulation to allow fresh air into the vehicle.

[McCassandra]

There is actually no strict time limit for how long the interior air recirculation can be turned on. In theory, it can be left on continuously, but it's best not to keep it on for too long as it can lead to poor air circulation inside the car. As someone who drives frequently, I've noticed that if the interior air recirculation is on for more than half an hour, the rising carbon dioxide levels can cause dizziness and drowsiness, which can affect safe driving. Even worse, in cold and humid weather, the windows are prone to fogging up, making it difficult to see the road. Therefore, I recommend manually switching to the exterior air circulation every 20 to 30 minutes for a few minutes to restore fresh air. Modern cars have an automatic mode, but manual control is also simple—just make it a habit. Especially during long-distance driving, it's important to flexibly adjust between interior and exterior air circulation to ensure comfort.

[ElenaRose]

I've always been concerned about the air quality inside the car when using recirculation mode for extended periods. The air becomes stuffy, and the rapid accumulation of carbon dioxide can lead to increased fatigue and even affect driving concentration. My usual practice is to use recirculation mode to filter external pollutants, such as during traffic jams or in dusty areas, but I never keep it on for more than half an hour before switching to fresh air mode to let in outside air and avoid discomfort. When using recirculation for long periods, it's also important to be mindful of the air humidity, as high humidity increases the risk of window fogging, which can easily lead to accidents. Therefore, I recommend adjusting the mode based on speed and environmental conditions rather than sticking to one setting. Driving safety is also related to these small details.

[MacAriel]

In my personal experience, keeping the air recirculation on, especially in summer with the AC running, saves fuel and cools the cabin quickly. However, don't leave it on for too long, as the air can become stale and windows may fog up. I usually switch to fresh air mode every so often—like after 30 minutes of city driving or an hour on the highway—for a few minutes to balance things out. It's a simple habit that maintains comfort without wasting fuel during daily driving.