Do You Need to Turn on the Internal Circulation When Using the Car's Air Conditioning?

[LeOmar]

Yes. The situations where internal circulation is needed are as follows: 1. During traffic jams: The more congested the traffic, the higher the density of exhaust fumes in the air. Turning on the internal circulation at this time can effectively prevent external exhaust from entering the car, thereby avoiding harm to the body. 2. In bad weather: When driving in dusty or sandy conditions, it is essential to activate the internal circulation. This not only prevents external dust from entering the car but also reduces the impact of dust on the air conditioning filter. 3. When cooling with air conditioning: In summer, when the air conditioning is on for cooling, turning on the internal circulation keeps the cold air inside and the hot air outside, reducing the load on the air conditioning and improving cooling efficiency. 4. When parked in an underground garage for a long time: If the car is idling in an underground garage for an extended period, internal circulation should be activated. Compared to the outside, underground garages have much poorer ventilation, and exhaust fumes can accumulate around the car if not quickly dispersed. Additional Information: Situations where external circulation is needed: 1. New car usage: After purchasing a new car, it is advisable to use the external circulation as much as possible to maintain airflow between the inside and outside of the car, helping to release harmful gases more quickly—similar to opening windows in a new house for ventilation. 2. Smoking in the car: For those who smoke in the car, it is important to turn on the external circulation while smoking, whether the car is stationary or moving, to ensure the smoke is quickly expelled. This not only protects your health but also reduces exposure to secondhand smoke for others in the car. 3. Long-distance highway driving: If internal circulation is used continuously, it can lead to insufficient oxygen inside the car, causing driver fatigue and increasing the risk of accidents. In such cases, switching to external circulation helps replenish fresh air inside the car.

[AshlynFitz]

When I turn on the AC while driving, I usually prioritize the recirculation mode first. It quickly reuses the cool air inside the car, making the AC compressor work more efficiently, resulting in faster and stronger cooling—especially in the peak of summer, which saves a lot on fuel costs. However, staying in recirculation mode for too long can make the air stale and cause passengers to feel dizzy, so I typically switch to fresh air mode for about 10 seconds every 15 to 20 minutes to ventilate, which also helps defog the windows. In areas with heavy air pollution or during traffic jams, I keep recirculation on longer to prevent exhaust fumes from entering, ensuring a comfortable ride. The key takeaway: Use recirculation first when cooling down for quick results, then briefly switch to fresh air periodically once the temperature stabilizes—this balances fuel efficiency and air quality.

[AdrianaLynn]

From a health perspective, I believe using the AC with recirculation mode is crucial. The recirculation mode blocks external hot air, allowing the AC to efficiently cool the air inside the car. However, the downside is that it can easily accumulate carbon dioxide and moisture. Prolonged lack of air exchange can lead to drowsiness or fogged windows, which is unsafe. My family has a small habit: when turning on the AC, we first use recirculation mode for 5 minutes to cool down the car, then switch to fresh air mode briefly to introduce fresh air and prevent oxygen deprivation. On rainy days, this also helps clear fog. I also pay attention to the condition of the AC filter—if it's dirty, it affects air exchange efficiency. Regularly checking it and switching between recirculation and fresh air modes ensures my family breathes comfortably and drives safely.

[Doug]

From the perspective of automotive components, using the air conditioner with internal circulation has many benefits. Internal circulation directly processes the cool air inside the car, reducing the cooling load on the compressor, making the air conditioning system more durable and consuming less fuel. However, prolonged use of internal circulation can increase interior humidity, leading to odor or mold issues that affect driving comfort. My recommendation: Use internal circulation to cool down quickly when starting, then switch to external circulation for ventilation once the temperature is comfortable. Simple maintenance like cleaning the vents can make switching between internal and external modes smoother, enhancing the overall experience.

[CalebAnn]

In terms of fuel economy, using air conditioning with recirculation mode can significantly save fuel and money. Recirculating cool air reduces AC energy consumption. I tested that recirculation mode allows 5% more mileage than fresh air mode while saving fuel, but don't overdo it. Excessive recirculation forces people to increase AC usage due to stale air, raising energy costs. My approach is: use recirculation during peak heat for rapid cooling, and switch to fresh air mode in mornings/evenings for ventilation - this balances expenses and maximizes comfort.