Should You Use External or Internal Air Circulation for Car Heating in Winter?
2 Answers
For short trips, you can use internal air circulation, while for long-distance driving, it is recommended to switch to external air circulation to replenish fresh air. Here is more information about car air circulation modes: 1. Car air conditioning systems have both internal and external circulation modes. Learning how to use them correctly ensures the health of passengers. 2. In winter, car air conditioning is used almost daily, as it provides both heating and cooling. 3. The heating principle of car air conditioning is much simpler than cooling. When heating, high-temperature coolant from the engine flows through the heater core, and the air blown by the fan passes over the heater core, allowing warm air to be emitted from the vents. 4. The cooling principle is slightly more complex. During cooling, the engine drives the compressor, which compresses refrigerant and delivers it to the evaporator. 5. The refrigerant expands and absorbs heat in the evaporator, cooling it. The cooled evaporator then cools the air from the fan, allowing cold air to be emitted from the vents. 6. Car air conditioning typically uses R134a refrigerant, which needs to be replaced periodically. It is advisable to replace the refrigerant on time; otherwise, the cooling speed may slow down, and the cooling effect may deteriorate.
I've been driving for over a decade, and in winter when turning on the heater, I usually start with the recirculation mode first. This way the warm air comes out faster and the car heats up quicker, especially in the morning when starting the car with outside temperatures below freezing. With recirculation on, the interior warms up in just five minutes. But you have to be careful not to keep it on all the time, otherwise the windows can fog up easily, and heavy fogging can dangerously obstruct visibility. I've experienced this before and quickly switched to fresh air mode, which cleared the fog immediately. Some newer cars come with an automatic mode where the air conditioning automatically switches between recirculation and fresh air based on temperature and humidity, making it much more convenient. My suggestion is to start with recirculation to heat up the car, then switch to fresh air after about ten minutes to maintain good air quality. Also, check that the air filter isn't clogged, otherwise the air can become stale. In short, adjust flexibly based on driving conditions for both safety and comfort.
