How to Distinguish Between Internal and External Air Circulation in a Car?

[DiRebecca]

Methods to distinguish between internal and external air circulation: Internal circulation closes the airflow channels between the inside and outside of the car. When the fan is turned on, there is no airflow circulation, and the air drawn in by the fan comes solely from inside the car, creating an internal airflow cycle. External circulation uses the fan to draw air from outside into the car, meaning the air ducts between the outside and inside are open. The air blown by the fan comes from outside the car, and even if the fan is not turned on, airflow is still drawn into the car while driving, replenishing the fresh air inside. Internal circulation primarily serves to promptly and effectively block external dust and harmful gases from entering the car, such as when driving through areas with smoke, dust, unpleasant odors, or in heavy traffic, preventing harmful exhaust emissions from the vehicle ahead. Another function is to maintain the interior temperature.

[OLevi]

When I was a driving instructor, I taught many new students how to distinguish between the car's air recirculation modes. The recirculation switch on the air conditioning panel usually has icons: the internal recirculation is represented by a car-shaped pattern with a rotating arrow inside, meaning the air inside the car is reused without bringing in fresh air from outside. This is suitable for use in highly polluted areas or during traffic jams, as it reduces the intake of exhaust fumes and dust from outside, and also helps the air conditioning cool or heat the car more quickly and efficiently. The external recirculation icon is an arrow pointing from outside the car inward, representing the introduction of fresh air, which is used when the air is clean or to prevent window fogging in humid conditions. The switch button only needs to be pressed once, but avoid using internal recirculation for too long, as the air can become stale and stuffy. Generally, use internal recirculation in traffic jams and switch to external recirculation on highways for better health and comfort. Regularly cleaning the air conditioning filter is also crucial.

[LeMaci]

As a driving enthusiast with over a decade of experience, I prioritize efficiency. The recirculation mode only circulates the air inside the car, making the air conditioning more fuel-efficient, especially when quickly adjusting the temperature in cold or hot weather. For example, switching to recirculation for the first two minutes after starting the AC helps stabilize the cabin temperature quickly, then switching to fresh air mode allows for fresh air circulation. The fresh air mode introduces outside air, useful in windy or humid conditions to prevent fogging and enhance safety. Operationally, look for the buttons in the AC control area: the recirculation symbol is usually an arrow looping inside the car, while the fresh air mode is an arrow pointing outward. Switch modes based on weather: use recirculation more under the sun to save energy, and switch to fresh air in rain or snow for ventilation. Avoid staying in one mode for too long to prevent stale air from affecting driving focus—this is the smart choice.

[EvangelineMarie]

When taking care of children in the car, I pay special attention to the difference between recirculation modes. The recirculation mode reuses the air inside the car without drawing in fresh outside air, which is effective in protecting children from allergies in areas with heavy pollen or pollution. However, on foggy days or when there are odors inside the car, it's necessary to switch to the fresh air mode: letting in fresh air to reduce fogging and remove odors. Look at the buttons on the air conditioning panel: a single button can switch between modes. The recirculation icon looks like an arrow circling inside the car, while the fresh air mode shows an arrow coming into the car from outside. Use it during daily commutes, adjusting according to the environment for safety and health. Also, remember to regularly check and clean the air conditioning system.