Which Circulation Mode to Use When Parking?
3 Answers
When parking, the choice between using the internal or external air circulation mode depends on the vehicle's system settings or the external air quality. For long-term parking, practical considerations should also be taken into account. If the air is fresh, use the external circulation mode; if the air quality is poor, switch to internal circulation. In winter, it is recommended to use the internal circulation mode. Some vehicle models are designed to automatically select the internal circulation mode after parking and turning off the engine, while others may default to external circulation. This is determined by the vehicle's design and ventilation system, requiring no manual selection by the driver. For vehicles without preset modes, the decision can be based on environmental conditions. For instance, in humid, dusty, or odorous environments, using the internal circulation mode helps maintain clean, dry air inside the car. During the damp weather of winter and spring, especially in southern regions where humidity is high, internal circulation is advisable to prevent moisture from affecting the car's interior, such as dampening the seats. For extended parking periods, the internal circulation mode is best to ensure the interior remains clean and dry.
I remember when parking, it's generally recommended to turn on the recirculation mode. When the car is idling while parked, if the external circulation is turned on, exhaust fumes from outside may enter the car, especially in parking lots or traffic jams, which can be harmful to health if inhaled. After driving for so many years, I've found that when waiting for someone during long stops, turning on recirculation makes the air conditioning more effective at cooling or heating, avoids external dust and noise interference, and also saves a bit of fuel. Of course, if parked in a fresh-air outdoor setting, you can briefly turn on external circulation for ventilation, but not for too long. The key is to pay attention to the air quality inside the car and not let passengers feel stuffy. Be cautious about battery load when running the AC while parked, especially with older cars that are prone to battery drain. In short, recirculation is safer and more practical.
I usually turn off the air recirculation system or switch to the internal circulation mode when parking. When the engine is idling, it generates heat and emissions, and the external circulation mode can draw these exhaust fumes and dust into the car, which is harmful to the respiratory system. Given the current pollution levels, I'm quite concerned about environmental protection and believe that air quality should also be considered while driving. From a fuel-saving perspective, using internal circulation reduces the air conditioning load and extends engine life. When waiting at a red light or in traffic, briefly switching to internal circulation is sufficient; if you have to wait for a while, it's better to turn off the engine, which is both eco-friendly and cost-effective. Some modern cars have automatic features that switch circulation modes, but manual control feels more reassuring. Remember, reducing unnecessary air conditioning usage is beneficial for the environment.
