Should the car use internal or external air circulation when turning on the cold air?

3 Answers
Lucy
07/28/25 11:16pm
When turning on the cold air in a car, you can choose either internal or external air circulation. The car air conditioning system refers to the air conditioning device installed in the car, and its functions are: 1. It can cool, heat, ventilate, and purify the air inside the cabin; 2. It provides a comfortable environment for passengers, reduces driver fatigue, and improves driving safety. The car air conditioning system includes cooling devices, heating devices, and ventilation devices. This combined system makes full use of the limited space inside the car and has a simple structure for easy operation. The car air conditioning system mainly consists of a compressor, electronically controlled clutch, condenser, evaporator, expansion valve, liquid storage dryer, pipes, condenser fan, vacuum solenoid valve, idle speed controller, and control system.
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MacSawyer
08/12/25 2:37am
When you first start driving and want to turn on the cold air, I recommend pressing the recirculation button first to quickly cool down the cabin. This is because the AC will only circulate the air inside the car, preventing hot external air from entering and disrupting the cooling effect, resulting in faster cooling. However, don’t stay in recirculation mode for too long. After about ten minutes, switch to fresh air mode to introduce fresh air and avoid stuffiness or dizziness caused by carbon dioxide buildup, which is not ideal for long-distance driving. In heavy traffic or areas with severe air pollution, such as when waiting at traffic lights, recirculation can block out dirty external air, protecting your respiratory health. On highways with less traffic, switch to fresh air mode for a comfortable breeze. Combined with AUTO mode, the AC will switch automatically, making it effortless. Remember, the key is to adjust flexibly based on actual road conditions—this ensures a comfortable and safe drive while also saving some fuel costs.
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DeMatteo
10/01/25 5:29am
Don't overlook the recirculation mode when using the car's AC, considering health implications. Starting with internal circulation cools the cabin faster by recycling existing air, but prolonged use can lead to stale air, potentially causing fatigue or minor health issues. I've experienced this firsthand—feeling stuffy and groggy after extended internal circulation. Now, I switch to external circulation after five minutes of cooling to refresh the cabin with oxygen. In poor air quality conditions like pollen season or industrial areas, I maintain internal circulation to avoid harmful particles. Also, remember to clean or replace the AC filter regularly to ensure clean airflow—no shortcuts here. This practice significantly benefits health, making family trips safer.
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