Should the Car Air Conditioner Use Internal or External Circulation?
2 Answers
Whether to use internal or external circulation for the car air conditioner depends on different situations: 1. Use internal circulation during traffic jams to prevent polluted air from outside from entering the cabin; 2. Use external circulation during long-distance driving to allow fresh air from outside to enter the cabin, avoiding low oxygen levels inside. The function of internal circulation is to promptly and effectively block external dust and harmful gases from entering the car, with faster cooling and heating effects. The function of external circulation is to supplement fresh air, maintaining air circulation between the inside and outside of the car, which helps keep the air inside the cabin clean. The internal circulation of the car air conditioner is located below the front dashboard in the driver's compartment, while the external circulation is located below the windshield on the passenger side of the engine compartment.
When I first started driving, I used to struggle with this issue too, but now I've figured it out: In summer, if you want to cool down the car quickly with AC, just press the recirculation button—it recycles the cool air inside, making cooling faster and more fuel-efficient. However, on long trips or rainy days, be careful not to keep recirculation on for more than twenty minutes continuously, as the windshield can fog up easily. That's when you should switch to fresh air mode to defog. Personally, once the car's temperature drops, I switch to fresh air mode on highways—it prevents stuffiness and keeps the air fresh. If stuck in traffic or passing by chemical plants, I immediately switch back to recirculation to keep exhaust fumes and odors out.
