What Air Circulation Mode to Use When the Car Fogs Up in Summer?
2 Answers
In summer, when the car interior fogs up, use the external air circulation mode. Solutions for defogging the car interior include: 1. Open both side windows; 2. Adjust the air vents to defogging mode; 3. Reduce the temperature difference to eliminate fogging; 4. Wipe the windows with a cloth soaked in dish soap or soapy water. Causes of car interior fogging are: 1. When humidity is high, the window temperature is below the dew point; 2. When the temperature is too low, the window surface becomes saturated with moisture, and the vapor pressure is lower than the surrounding environment; 3. There is a certain temperature difference between the two sides of the window; 4. Large temperature difference between the inside and outside of the car; 5. Damp car floor mats. Methods to prevent car interior fogging include: 1. Use anti-fog wipes to clean; 2. Apply anti-fog spray in advance.
As someone who has worked on countless cars, I can tell you that in summer, you must use the external air circulation to defog the car—it's the most effective method. The reason is that summer brings high temperatures and humidity, and the external air circulation draws in dry outside air, which, combined with the AC cooling, quickly reduces interior humidity and eliminates fog. If you use internal circulation, the moisture keeps recirculating inside, causing faster and harder-to-remove fogging. When operating, first set the AC to AUTO mode at a low temperature, then press the external circulation button, avoiding direct airflow onto the glass to prevent temperature differences from worsening fogging. Also, check if the cabin air filter is clogged, which could affect airflow, or if the windshield is too dirty and prone to trapping moisture—wipe it clean with a slightly damp cloth. These small details ensure clear visibility and safe driving while also extending your AC's lifespan, saving fuel and hassle.
