Should You Use Air Conditioning or Heating to Defog Your Car in Winter?
2 Answers
Driving with fogged windows generally requires using air conditioning in mild climates and heating in winter. Here are specific methods to solve the problem of fogged windows while driving: 1. Use heating to defog. In cold weather, when the car's heating is on, adjust the air vents to blow onto the windshield. If the fog is heavy, increase the fan speed to quickly clear the fog. However, there is a drawback: do not wait until fog appears to start defogging. If you turn on the heat while driving and fog has already formed, it may temporarily worsen, making the windshield increasingly blurry and dangerous! Therefore, it's best to start the defogging process as soon as you start the car. 2. Use a dedicated defogging spray. There are many defogging products available on the market that are simple to use—just spray them onto the windshield and wipe clean with a dry towel. This creates a thin, transparent protective film on the glass, preventing water vapor from condensing into fog on the cold surface. The defogging effect can last for about one to two weeks. 3. Open the windows to defog. Opening the windows allows the inside temperature to equalize with the outside temperature, causing the fog to disappear. This method has many limitations and is suitable only when the temperature is not too low. It is not recommended during rainy or extremely cold weather. Most modern vehicles come with a one-touch defogging function—simply turn it on when fog appears, making the process convenient and quick. Next time you encounter fogged car windows, be sure to choose the right method to clear them faster.
I've been driving for many years, and fogging issues in winter are particularly common, especially after a cold start. The fog forms when the moisture from our breath inside the car condenses on the cold glass. To deal with it, the best approach is to first turn on the AC by pressing the AC button for dehumidification—this will quickly clear the windshield. Using the heater also works, but it's slower and might cause more condensation as the glass warms up. Nowadays, as soon as I notice fogging, I immediately turn on the air conditioning, switch to defrost mode (directing airflow toward the windshield), and set the heater to a moderate temperature for comfort and safety. Always remember: safety comes first. Slow down or pull over to handle fogging—don’t risk driving fast. Developing good habits, like turning on the external air circulation for ventilation when you start the car, can help reduce fog buildup. I’ve used these tips countless times on the road, and I’m sharing them to help you out.
