Which Circulation Mode to Use for Long-term Parking?

[DiCatherine]

When parking for an extended period, the appropriate circulation mode should be selected based on actual conditions. Here are the details: 1. External Circulation: This mode draws air from outside the vehicle, directs it through the air conditioning system for heating or cooling, and then blows it out through the vents. External circulation replenishes fresh air and improves cabin air quality. However, in extremely hot and dry weather, using external circulation requires the AC compressor to work continuously to cool the incoming hot air, which consumes additional fuel. 2. Internal Circulation: This mode recirculates the existing cabin air. The AC system draws in cabin air, cools it, and then returns it to the cabin. Once the cabin temperature reaches the set value, the AC compressor disengages, reducing engine load. Therefore, the faster the cabin temperature reaches the set value, the sooner the engine load decreases, resulting in lower fuel consumption.

[StLeilani]

I remember driving for decades and got used to turning on the external air circulation when parked for long periods, like waiting for someone at a highway rest stop. The reason is simple: internal circulation only blows air from inside the car. It feels cool at first, but after half an hour, the air becomes stale, making it hard to breathe and easy to feel dizzy or drowsy. Once, I parked by the roadside with internal circulation on and almost suffocated in my sleep—it scared me to death. Now, I always remind myself to press the external circulation button before starting the AC to bring in fresh air. This way, the windows don’t fog up, and the car doesn’t feel stuffy. Especially in summer or winter, when parked with the AC on for long periods, it’s both safe and comfortable. Developing this habit helps avoid accidents.

[SanBenjamin]

I care a lot about health, so I always prefer the external air circulation mode when parked for long periods. Internal recirculation can cause carbon dioxide to build up inside the car, leading to breathing difficulties over time, and may even cause fatigue or dizziness, which is especially dangerous for elderly people and children. External circulation brings in fresh air from outside, keeping the air inside fresh. If parked in a non-polluted area, such as next to a park, turning on external circulation allows you to enjoy fresh air. I often park to read or rest, using the air conditioning along with external circulation, and after an hour, I still feel refreshed. I recommend combining this with opening the windows for a few minutes to ventilate, which can help prevent air quality issues.

[KennedyLynn]

Want to save fuel and be eco-friendly? Using the external air circulation mode during long stops is more economical. Internal circulation speeds up AC cooling or heating but consumes slightly more fuel; external circulation reduces engine load, saving some gasoline. After driving for ten years, my fuel consumption statistics show about 5% savings when using external circulation during stops. Better air flow keeps the car odor-free and avoids energy waste. For example, when waiting in a mall parking lot, using external circulation is both environmentally friendly and cost-effective.