Does the car fog up on the outside or inside when the air conditioning is on in summer?
3 Answers
When the air conditioning is on in summer, the car fogs up on the outside. Precautions for using air conditioning in summer: 1. Do not turn on the air conditioning immediately after exposure to the sun: Many cars are exposed to the scorching sun in summer, and many people tend to start the car immediately, turn on the air conditioning, and set the fan speed to high to achieve the fastest cooling effect. In fact, this is not reasonable. After starting the car, lower the windows on both sides first to allow outside air to circulate, which can quickly reduce the temperature inside the car. 2. Avoid using the recirculation mode for extended periods: The recirculation mode works by circulating air within the enclosed space of the car, which leads to a continuous decrease in oxygen levels inside the car. Moreover, if the gasoline in the cylinders does not burn completely, unburned carbon monoxide from the engine may leak into the cabin, causing the air quality inside the car to deteriorate and even posing health risks. When the car is stuck in traffic in a busy urban area or driving against the wind, the recirculation mode can be used to prevent exhaust fumes from entering the car and ensure the air inside remains unpolluted; at other times, it is recommended to use the fresh air mode as much as possible.
Having driven for decades, I often notice that when I turn on the AC in summer, fogging always occurs on the outside of the windows. The hot and humid outside air meets the cold windshield inside, immediately condensing into dew, just like sweat on an ice-cold beer bottle. During my long-distance drives, this becomes even more noticeable on rainy or foggy days, blurring visibility and posing a real danger. Quickly turning on the wipers can clear it right away. For prevention, avoid setting the AC temperature too low—large temperature differences make fogging more likely. I often adjust the air vents to blow upward, avoiding direct airflow on the glass, or switch to a bit of outside air circulation. Regularly check your wipers for wear and tear, and prepare in advance on high-humidity days. These small things add up with experience—safety comes first when driving, especially when carrying family. Stay alert.
As a young car enthusiast, I was curious about why fog forms on the outside of car windows when the AC is on in summer. The principle is simple: cold glass meets hot air, causing condensation on the outside, unlike winter when fog forms inside. My new car comes with a smart AC feature that automatically balances temperature differences to reduce fogging. On highways, turning on the wipers clears the fog instantly. I also experimented with anti-fog spray applied to the outside of the glass, which worked well. Remember to set the AC temperature not too low, and use a small fan or adjust the vents on humid days. These small tweaks make driving more comfortable and safer, especially during hot summer trips—don’t overlook them.
