Should You Use Cold or Hot Air for Windshield Fog?
2 Answers
If you're defogging in winter, you need to use warm air; if you're defogging in summer, you need to use cold air. Here are some additional points about windshield fogging: 1. Fogging on car windows is very common. The main reason for fog formation is the condensation of moisture when it meets cold surfaces. This significantly impairs the driver's visibility and creates potential hazards for traffic accidents. 2. Using the car air conditioning's cooling function can effectively achieve defogging. In addition to cooling, using the air conditioning's heating function to dry the moisture inside the car can also achieve defogging. However, it's important to note that when you turn on the hot air, the fog may suddenly increase, so you must park the car before using hot air for defogging.
I often encounter fogging on the windshield while driving, especially during winter mornings when taking my kids to school. Initially, I would use the cold air setting because it quickly removes the fog—it takes just a few seconds to work—but the car gets too cold, and the kids start shivering. So, I usually switch to the warm air mode and wait a bit. Although it takes longer to defog, once the car warms up, the fog is less likely to accumulate again, as warm air dries out the source of moisture inside the glass. I find this method quite practical: start the car, use the external circulation with cold air to defog first, then switch to internal circulation with warm air to maintain the temperature. This also reduces the temperature difference between the inside and outside of the car, preventing fog from recurring. Sometimes, cracking the side windows slightly for ventilation helps, speeding up the defogging process. In short, adjust flexibly according to the situation—safety comes first.
