Should you use internal or external air circulation when turning on the car's air conditioning?
2 Answers
When turning on the car's air conditioning, it is recommended to use external air circulation. The air conditioning system has two circulation modes: internal and external. Below is relevant information about internal and external circulation: 1. Internal circulation means the air inside the vehicle is recirculated, where the air from the vents comes from inside the cabin, which is sealed off from the outside atmosphere. External circulation means outside air enters the cabin, with the vent air coming from outside, connecting the cabin to the external atmosphere in an unsealed manner. 2. Internal circulation only involves the blower circulating air within the car's interior. Since no outside air is involved, it offers advantages of fuel efficiency and faster cooling (or heating), but the drawback is poorer air quality refreshment inside the car. External circulation means the blower draws fresh air from outside into the cabin, with the advantage of maintaining better air quality inside, though cooling (or heating) is slightly slower and consumes more fuel.
Having driven for so many years, I've developed the habit of turning on the recirculation mode first when using the AC in summer. This allows the air conditioning to focus on cooling the air inside the car without wasting energy on the hot air outside, making the car cool down faster and saving a bit of fuel. I remember a long trip two years ago when the car was unbearably stuffy in the scorching heat. As soon as I turned on recirculation, the cold air blew in instantly, and the temperature dropped comfortably. However, using recirculation continuously can make the air feel stagnant and stuffy. After sitting for a while, I often feel dizzy and lightheaded, so I switch to fresh air mode (outside air) after about half an hour to let in some fresh air. This maintains the coolness while avoiding health issues. If there are many passengers in the car or a strange odor when starting up, it's best to use fresh air mode for a few minutes to ventilate before switching to recirculation. This also makes the driving experience more pleasant.
