It is very common for the windshield to fog in winter, and most drivers will encounter it. During summer driving, fogging is not very common, but many people have also encountered it and do not know the method of removing fog, which greatly affects their visibility and makes driving unsafe. In winter, the fog only needs to turn the air conditioning wind direction to the direction of blowing the glass, and soon the fog will dissipate. But in summer, it has the opposite effect. The more it hits the direction of blowing the glass, the greater the mist, and it cannot be wiped off with a towel. What is this? How should I remove the fog?

Firstly, we need to know that the fog on the glass in summer is outside the glass, while in winter it is inside the glass. Therefore, in winter, wiping with a towel can remove the fog, but in summer, wiping with a towel cannot work, and the fog cannot be wiped outside. The principle of fogging is the same. When humid air with higher temperatures encounters glass with lower temperatures, it releases heat and liquefies into small water droplets, which attach to the window glass and form fog. In winter, when the warm air is turned on, the air temperature inside the car is high and the glass temperature is low, resulting in fogging inside. In summer, when the air conditioning is turned on, the opposite happens. The outside air temperature is high, the interior temperature is low, and the temperature of the car glass is also low, resulting in fogging outside. Misting requires two conditions: humid air and temperature difference, both of which are indispensable. Generally, on cloudy and rainy days with high external air humidity and air conditioning inside the car, it is easy to get foggy, which just meets the two conditions for fogging. On sunny days, fogging does not occur because the air is not humid.

There are two ways to remove fog, the first is to use a rain brush, which is the most direct method because the fog is on the outside of the glass, and the rain brush can directly brush it. When brushing, spray water instead of dry brushing. Although there is fog on top, it is only slightly below the windshield and not elsewhere. Some wipers may not be clean on a regular basis, and dry brushing may make them more blurry, resulting in a better effect with a water spray brush. As long as there is fog, brushing it is relatively troublesome. The second method is to use air conditioning to blow, but cold air cannot be used. Using cold air will become more severe as it will blow the temperature of the car glass lower. Turn up the temperature of the air conditioner and then blow the glass. The higher the temperature, the faster the mist dissipates. The principle is to blow the glass hot, so that there is no temperature difference between the glass and the outside air, and the mist will not condense on the glass. The already condensed mist will also evaporate immediately.

So when driving in the summer, it is best to turn on the air conditioning. The wind direction should not be towards the windshield, and it should be blown forward. The air outlet should be turned up, which means the wind should be blown diagonally upwards. This way, the cool air will circulate in the car and the interior will be cooler. If you keep blowing the glass, the interior of the car will not be too cool, especially in the rear seat area, because the cold air cannot circulate. Just like a household air conditioner, the wind direction needs to blow indoors. If you blow towards the window, the interior will definitely not be so cool. Secondly, the windshield is more prone to fogging, as blowing the glass continuously will make it cool, resulting in a significant temperature difference between the glass and the outside air. A slight increase in external humidity will cause fogging.

From: WONDEE Autoparts 2023-10-23