Does turning on the air conditioning in the car in summer cause fogging on the outside or inside?
2 Answers
It occurs on the outside. Here is some extended knowledge: 1. In a stuffy summer car with the air conditioning on, since the temperature inside the car is lower than outside, the water vapor in the outside air will condense when it meets the cold car windows, causing fogging on the outer surface. 2. In cold winter, the temperature inside the car is higher than outside, so the water vapor in the inside air will condense when it meets the cold car windows, forming fogging on the inner surface of the windows. Solutions for fogging inside the car: 1. After the engine warms up, turn on the heater and temporarily close other air vents, directing the airflow straight at the window surface to quickly disperse the fog. 2. Turn on the air conditioning, adjust the interior temperature to eliminate fogging inside the car, allowing the window frost to melt quickly. 3. Apply a thin layer of glycerin or alcohol on the windshield to prevent frost formation on the glass surface for a short period. 4. Dissolve dishwashing liquid in water and apply it to the inside of the windshield with a clean cloth. Many bubbles will form, but they will disappear after a while, leaving a film of detergent that effectively prevents frost formation on the glass for up to two hours. 5. If frost forms on the windshield, stop the car to scrape off the frost and wipe it clean with a dry towel. Avoid driving with frost or wiping while driving to ensure safety.
I've been running an auto repair shop for nearly twenty years, and this issue pops up every summer. Fogging on the outside of car windows happens when the AC blasts cold air directly onto the glass while it's hot and humid outside—the temperature difference is as stark as opening a fridge door. It's the opposite of winter fogging inside the car. The solutions are straightforward: First, avoid pointing the AC vents straight at the windshield. Second, roll down the windows for a few seconds to balance the inside and outside temperatures. Third, using the wipers gives instant relief in a pinch. Seasoned drivers know the best trick is cooling the car in advance—remotely starting the AC ten minutes before getting in prevents both fogging and a scorching seat.
