Should You Use Internal or External Air Circulation When Turning on the Car Heater?
1 Answers
When turning on the car heater, it is recommended to use the external air circulation mode. Internal circulation is used to block out polluted air, while external circulation is for bringing in fresh air. The specific choice depends on the situation. In winter, if you want to quickly warm up the car interior, you can first start the engine and drive normally for a while to allow the engine to warm up. Once the temperature gauge needle reaches the middle position, turn on the heater with internal circulation. Using internal circulation allows the air conditioning system to rapidly cool or heat the car interior. This not only warms up the car quickly but also avoids placing extra burden on the engine, resulting in better fuel efficiency. Although continuous internal circulation keeps the car warm, the interior becomes a relatively sealed environment. Prolonged exposure to such conditions can lead to oxygen deprivation. Therefore, it's best to switch to external circulation every hour to draw in fresh air from outside. The air then passes through the air conditioning evaporator or heater core to deliver either cool or warm air. External circulation is generally recommended in most situations, especially during long-distance driving. If internal circulation is used for too long, fresh air cannot enter the car, and the same air keeps recirculating. As oxygen levels decrease, passengers may feel drowsy, and the driver may become even more fatigued, potentially leading to oxygen deprivation.
