Should You Use Internal or External Air Circulation When Turning on the Heater in Winter?

[GiselleFitz]

Whether to use internal or external air circulation when turning on the heater in winter depends on the situation: use internal circulation for short trips and external circulation for long trips. Internal and external air circulation in cars refer to: 1. Internal circulation means the air conditioning system is closed to outside air and can only circulate the air inside the car; 2. External circulation means the air conditioning system is open to outside air and draws in air from outside the car for circulation. The functions of a car's air conditioning system are: 1. To cool, heat, ventilate, and purify the air inside the car; 2. To provide a comfortable environment for passengers, reduce driver fatigue, and improve driving safety.

[DelJoy]

As a seasoned driver with years of experience, I've encountered the issue of using car heaters in winter countless times. I believe the key lies in balancing rapid heating and anti-fogging needs. When you first get into a freezing cold car, decisively turn on the recirculation mode - this makes the warm air circulate inside the vehicle, heating up incredibly fast. You'll feel warm within seconds. However, keeping recirculation on continuously leads to poor air circulation, and the moisture from breathing will cause windows to fog up, seriously compromising visibility and safety. Therefore, after 5-10 minutes, promptly switch to fresh air mode to let outside air in. This both defogs windows and prevents stuffy air, especially effective when carrying passengers or on long trips. Remember to slightly reduce fan speed before switching modes to avoid a sudden blast of cold air. Once this becomes habit, winter driving becomes much more comfortable and safer. I often recommend this method to novice drivers too.

[StJayla]

I often take my family out, and in winter, safety is always the top priority when using the heater. As soon as we get in the car, I turn on the recirculation mode to warm up the interior quickly, ensuring the kids don't get cold—warming their feet first. However, prolonged use of recirculation makes the air stale and causes windows to fog up easily, especially on rainy or snowy days, which can dangerously obscure the road ahead. After driving for a while, I switch to the fresh air mode to introduce outside air, defog the windows, and maintain sufficient oxygen levels. This keeps the whole family breathing healthier and prevents accidents caused by fogged-up windows. Don’t forget to alternate between the two modes regularly to balance interior temperature and air quality—a simple practice that significantly improves comfort and driving safety. I always keep this in mind every time I take the kids out.

[OEllie]

Young drivers prioritize efficiency, and turning on the internal circulation for heating in winter warms up the car super fast, making it instantly cozy when you get in. However, keeping it on internal circulation can cause windows to fog up, blurring visibility—especially unsafe on highways. Therefore, it's essential to occasionally switch to external circulation to refresh the air, preventing fogging while maintaining freshness, ensuring clear driving visibility without sacrificing warmth. Striking this balance isn't hard—just adjust based on the weather. After heating up with internal circulation, a simple button press solves the issue.