What Circulation Mode Should Be Used for Parking Air Conditioning?
3 Answers
Parking air conditioning should use the internal circulation mode. Below are the relevant explanations: 1. The correct way to turn on the car air conditioning is: first activate the external circulation to expel the hot air inside the car. After feeling a noticeable drop in the cabin temperature, switch to internal circulation. 2. Additional information: During city driving, especially in congested areas during rush hours or in tunnels, it is advisable to use internal circulation. However, when the car starts moving at a normal, steady speed, external circulation should be activated. Moreover, in dusty conditions, remember to close the windows and switch off external circulation to block external airflow. It is also best to set the air conditioning to internal circulation when parking, as external circulation can allow dust blown by the wind to easily enter the car, increasing the amount of dust inside.
Parking with the AC on requires extra caution for safety. I've seen too many cases where people fell asleep with the AC on while parked and nearly suffered carbon monoxide poisoning. When the car is stationary, engine exhaust accumulates around the vehicle, and using the external air circulation mode essentially draws all those toxic fumes inside. In my opinion, you must use the internal circulation mode and crack the windows slightly for ventilation—that's the safest approach. Enclosed spaces like underground garages are especially dangerous. Last year, there was a news report about someone who fell asleep while waiting in an underground garage with the AC on and never woke up. If you really need to rest, I suggest turning off the engine and opening the windows, or parking in a shaded area. After all, safety comes first.
I usually switch to recirculation mode when parking with the AC on, as it cools more efficiently and saves fuel. However, you can't keep it sealed all the time - rising CO₂ levels in the cabin can cause drowsiness. My routine is switching to fresh air mode for 1 minute every 15 minutes, or simply cracking the sunroof open. Last time at a highway rest area, this kept me cool without feeling stuffy. Pro tip: watch your battery when idling with AC - older cars shouldn't exceed 30 minutes to avoid a dead battery situation.
