Where Does the Air for the Car Air Conditioning Enter the Vehicle?

[LaHayden]

There are two air intakes for the car air conditioning system. One is the external circulation intake, located in the box with the cabin air filter beneath the windshield. The other is the internal circulation intake, which consists of two circular openings on either side of the dashboard inside the cabin. Most vehicles' external circulation intakes are equipped with air filtration devices, such as pollen filters or dust filters. However, most internal circulation systems do not have air filtration devices. Here is an extended explanation: 1. Internal Circulation: Internal circulation means the air blown by the blower only circulates inside the vehicle. Since no external air is involved, it can quickly heat up or cool down the cabin. This mode is suitable when first turning on the air conditioning, but it should not be used for too long, as prolonged use may affect the air quality inside the vehicle. 2. External Circulation: External circulation means the blower draws air from outside the vehicle and blows it into the cabin. This mode should generally be kept on, as it introduces fresh external air to maintain cabin air quality. When the external air quality is poor (e.g., on dusty roads), the external circulation can be temporarily turned off and switched to internal circulation.