Should You Use Internal or External Air Circulation When Using the Heater in Winter?
2 Answers
Whether to use internal or external air circulation when using the car heater in winter depends on the specific situation: 1. When to use internal circulation: To quickly heat up the car in winter, start the engine and drive normally for a while 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 to rapidly cool or heat the car interior. This not only warms up the car quickly but also avoids putting extra load on the engine, saving fuel. 2. When to use external circulation: Although continuous internal circulation keeps the car warm, the interior becomes a relatively sealed environment. Prolonged exposure to this condition can lead to oxygen deprivation. Therefore, it's best to switch to external circulation every hour to draw in fresh air from outside. This air then passes through the air conditioning evaporator or heater core, producing cool or warm air respectively.
I usually turn on the recirculation mode as soon as I get in the car, and the temperature rises very quickly—the cabin gets warm and cozy in less than three minutes. But I remember to switch to fresh air mode for ventilation after about half an hour, otherwise the windshield tends to fog up. Even wiping it with my fingers doesn’t help, and it becomes hard to see the road. Once, I forgot to switch, and the foggy windshield almost caused a rear-end collision. Now, I set a phone alarm to remind myself. If I encounter traffic jams or enter a tunnel, I quickly switch back to recirculation mode to avoid inhaling exhaust fumes.
