Should the Car's Heating Use Internal or External Air Circulation in Winter?

[AlanLee]

In winter, both internal and external air circulation are needed when using the car's heating. Start with internal circulation until the car warms up, then switch to external circulation. The heating system in winter should primarily use internal circulation, supplemented by external circulation, alternating between the two. This ensures the car stays warm while preventing a rise in carbon dioxide levels inside the car, which could affect driving safety. Internal circulation closes the external air intake grille, sealing the car completely and recirculating the interior air. However, prolonged use leads to decreased oxygen levels as temperatures rise, potentially causing hypoxia in a closed environment. Therefore, it's advisable to periodically switch to external circulation to let in fresh air. When external circulation is activated, the air is heated using the car's electric heating grid.

[DeAlice]

When using the heater in winter, I prefer to start with the recirculation mode first. The reason is simple: when the car is just started, the engine doesn't produce enough heat, and using recirculation allows the existing air inside the car to be heated repeatedly, warming up the cabin faster. This is much more efficient than drawing in cold air from outside via fresh air mode. Once the car is warm, I switch to fresh air mode to bring in outside air, preventing window fogging and stuffiness. Keeping recirculation on all day can easily cause windows to fog up, especially in humid weather, which is dangerous as it reduces visibility. Switching modes this way allows for quick warmth while maintaining driving safety. My advice: don't get greedy for fast heating and forget to switch to fresh air mode.

[SanLilah]

From an energy efficiency perspective, it's best to use the recirculation mode first when turning on the heater in winter. The warm air comes from the engine's waste heat, requiring no additional fuel consumption. Recirculation mode only heats the air inside the cabin, providing more efficient warming with reduced heat loss, allowing the car to heat up faster and saving time. Once the cabin is warm, switch to fresh air mode to introduce outside air, preventing stuffiness, dizziness, or windshield fogging. Fogging is common in winter and can impair visibility, increasing accident risks. Proper mode switching can also extend the heating system's lifespan. Don't overlook these details - safe driving is what matters most.

[DiJayden]

From a safety perspective, it is recommended to use the recirculation mode first to quickly warm up the car interior when turning on the heater. After the temperature rises, switch to fresh air mode to allow fresh air in, as prolonged use of recirculation can easily cause fogging or difficulty in breathing. Fogged-up windows obstruct visibility and make it difficult to drive fast, especially on icy or snowy roads, which can be very dangerous. This small detail is crucial for safe driving, so don't overlook it.