Should you use internal or external air circulation when turning on the car's air conditioning?

[OJohnny]

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.

[CassandraLee]

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.

[OJustin]

When driving with the AC on, my approach is simple: start by pressing the recirculation button to cool the hot air inside the car efficiently and quickly, which is especially fuel-saving for short trips without hassle. Once the interior temperature stabilizes, immediately switch to fresh air mode to allow outside air to flow in, preventing window fogging or stuffiness. On highways or in traffic jams, this strategy keeps the air fresh and reduces fatigue risks. Sometimes, I even open the windows briefly for ventilation before closing them and switching back to recirculation to maintain cooling. By alternating between recirculation and fresh air modes, not only is comfort ensured, but the AC system also experiences less wear. Periodically checking the air filter makes maintenance even more worry-free.

[DelMary]

When using the air conditioning, prioritize the recirculation mode to quickly cool down the car interior, but avoid prolonged use as stale air can cause dizziness and compromise driving safety. I personally adhere to a switching routine: start with recirculation to chill the air, then switch to fresh air mode after 20 minutes to maintain a balance between comfort and health. Use fresh air mode more often when outside air quality is good to prevent CO2 buildup; switch to recirculation in poor weather to minimize pollution. As a driver, this habit safeguards my family's health and ensures a more secure journey.

[JuliaFitz]

When I first started driving, I was completely confused about the air recirculation and fresh air modes. Later, I learned the basic rules: turn on recirculation mode first when starting the AC to trap the interior air for faster cooling, which is more efficient. Once the cabin reaches a comfortable temperature, switch to fresh air mode to replenish oxygen and prevent stuffiness. This simple yet effective operation helps beginners avoid health issues or reduced driving pleasure from using only one mode, while easily adapting to different environments with better AC control.

[MacAubree]

When using the car's air conditioning system, switching between internal and external circulation modes reasonably balances comfort and environmental protection. I first turn on the internal circulation to reduce energy consumption, as it provides higher cooling efficiency and puts less load on the compressor, saving energy. After the temperature drops, I switch to external circulation to introduce outside air, diluting pollutants and enhancing freshness while reducing odors inside the car. This habit extends the air conditioning system's lifespan, makes driving more relaxing and comfortable, and also contributes a small effort to reducing environmental impact.