How to Use the Internal and External Air Circulation in a Car?
4 Answers
Here are the methods for using the internal and external air circulation in a car: 1. Airflow: External circulation exchanges fresh air from outside the car to the inside, while internal circulation cuts off the airflow between the inside and outside of the car. Without turning on the fan, there will be no airflow inside the car. 2. Pay attention to air circulation when driving in the city, where the outside air quality is poor. At this time, turn on the internal circulation to prevent outside air from entering and causing pollution inside the car. 3. Temperature adjustment: To quickly warm up the car in winter or cool it down in summer, turn on the internal circulation to speed up the temperature regulation inside the car. 4. Circulation time: If the internal circulation is on for too long, switch to external circulation to allow fresh air to flow in. 5. Usage during rainy days: On rainy days, the windshield may fog up due to temperature differences inside and outside the car. When the humidity inside the car is high, turning on the external circulation can quickly clear the fog.
When I first started learning to drive, I was completely confused about the recirculation and fresh air modes. Later, I figured out how to use them, and it turned out to be quite simple. The button with a car icon and an arrow inside the car represents recirculation mode. When activated, the air circulates only within the car, keeping outside odors out and cooling the car faster with the AC on. The button with an arrow pointing from outside into the car is the fresh air mode, which draws in outside air, ideal for ventilation and preventing window fogging. While driving, if there’s heavy pollution or traffic, I switch to recirculation to avoid bad air. On highways or when the air is clean, I use fresh air mode to ventilate. The button is usually on the AC panel, toggled with a single press—don’t keep recirculation on too long, as it can make the cabin stuffy and reduce oxygen, making you drowsy. My habit is to start with fresh air mode to circulate air, then adjust as needed after a few minutes. Use fresh air to prevent fogging on rainy days and recirculation for quick cooling in summer. In short, use them flexibly based on conditions, and remember to switch off occasionally to let the air refresh.
After driving for over a decade, I've summarized a practical approach to using the air recirculation system. When starting the car cold in the morning, first use fresh air mode to clear stale air inside; immediately switch to recirculation mode in heavy traffic to block exhaust fumes; when using AC for heating or cooling, start with recirculation for faster temperature adjustment. The button operation is simple, but the key is not to overuse it: prolonged recirculation makes air stale, easily causing fogging and chest tightness - I set it to automatically switch to fresh air every 30 minutes. For cars with automatic AC, pressing AUTO enables smart adjustment, but manual control offers more flexibility. On highways I insist on fresh air mode for better airflow; for short city trips recirculation saves energy. Seasonal considerations matter too: use more fresh air in winter to prevent fogging, and start with recirculation after summer sun exposure. Locate the arrow-marked button on the center console - developing this habit makes driving more comfortable and safer.
I pay special attention to healthy car usage, and the air recirculation mode significantly impacts air quality. The recirculation mode blocks external pollution, but prolonged use can lead to stale air that's not good for breathing; the fresh air mode brings in outside air, which may carry pollen or dust. My approach: use recirculation mode during pollen allergy seasons or in highly polluted areas; switch to fresh air mode when driving in suburban areas with good air quality. The button is usually designed for one-touch switching—just press it once to change modes. Don't keep the recirculation mode on continuously to avoid CO₂ buildup that may cause dizziness; it's recommended to switch to fresh air mode for a few minutes every 20-30 minutes for ventilation. Combining this with slightly opening the windows is even better, especially when carrying passengers to maintain oxygen freshness. During commutes through smoky or dusty areas, prioritize recirculation mode, but turn it off on highways to ensure ventilation. A simple reminder: use fresh air mode when prone to fogging to prevent window blurring.
