Should the car air conditioning use internal or external circulation?

[RuthLee]

Whether to use internal or external circulation for the car air conditioning depends on the situation: use internal circulation for short trips and external circulation for long trips. Below is a relevant introduction to internal and external circulation: 1. Internal circulation means the air conditioning system is closed to external air and only uses the air inside the car for circulation. 2. External circulation means the car air conditioning system is open to external air, drawing in air from outside the car for circulation. Below is a relevant introduction to the functions of air conditioning: 1. It cools, heats, ventilates, and purifies the air inside the car. 2. It provides a comfortable environment for passengers, reduces driver fatigue, and improves driving safety.

[Freddie]

When I encounter traffic jams while driving, I usually switch to the recirculation mode to prevent exhaust fumes and dust from outside, especially those from trucks, from entering the car. Not only do they smell unpleasant, but they also easily degrade the air quality inside the car. When driving faster on highways, I switch to the fresh air mode to let in some fresh air, which helps me feel more alert. During summer when using the air conditioning for cooling, I prioritize the recirculation mode for faster cooling and better fuel efficiency. However, after prolonged use, it's important to switch to the fresh air mode for a few minutes to prevent excessive carbon dioxide buildup, which can cause fatigue and drowsiness. In cases of smog or when driving through tunnels, I definitely stick to the recirculation mode for health protection. Actually, most cars have an automatic mode, which is very convenient with just a press of a button.

[Ayla]

As a father, I'm most concerned about the impact of in-car air quality on my child. Using the recirculation mode is great when outside air pollution is severe, especially on city roads with lots of traffic lights, as it isolates polluted air. However, prolonged use of recirculation can decrease oxygen concentration, leading to drowsiness and affecting safety. Therefore, I recommend switching to fresh air mode for a few minutes every half hour. The fresh air mode is super useful during rainy days or when there are odors in the car, quickly ventilating to remove moisture and smells. My personal habit is to start the air conditioning with fresh air mode for 5 minutes to exchange air, then adjust according to the situation. Health is more important than convenience—don't forget to regularly clean the AC filter to prevent bacterial growth.

[Jacob]

From an energy-saving perspective, I've found that using the recirculation mode is most effective during the initial stage of air conditioning cooling. It only circulates the cooled air inside the car, reducing engine load and saving fuel. Using fresh air mode introduces hot outside air, which slows down the cooling process – especially unwise when it's 40°C outside. However, keeping recirculation on continuously leads to poor air circulation and may cause oxygen deprivation or dizziness. On long trips, I periodically switch to fresh air mode for 10 minutes to ventilate. Remember to use fresh air mode at high speeds to prevent pressure differential issues – a handy fuel-saving tip.

[MacTravis]

During rush hour in the city when traffic is congested, I prefer using the recirculation mode to block out exhaust fumes and protect respiratory health. For outings or on sunny highways, I switch to fresh air mode to let in clean air, which feels refreshing and prevents stuffiness. In winter rain, I use fresh air mode to prevent window fogging, while in summer with the AC on, recirculation cools the car faster. It also depends on personal habits - with more passengers, I use fresh air mode more often for ventilation, while recirculation suffices for solo commutes. Regular AC system checks are crucial.

[ZoeAnn]

Adjusting according to seasonal changes is the wisest choice. In the scorching summer, using the internal circulation accelerates air conditioning cooling, saving energy and improving efficiency. The significant temperature difference between the inside and outside of the car ensures a comfortable drive. In the cold winter, switching to external circulation prevents moisture condensation on the windows, avoiding fogging that could impair visibility, while also keeping the air fresh and not stuffy. During the transitional spring and autumn seasons, when pollen or dust is prevalent, using internal circulation can isolate these particles. However, it's recommended to switch modes daily to prevent fatigue caused by stagnant air. Driving safety is paramount, so timely maintenance of the air conditioning system is essential to avoid malfunctions.