Why does the windshield frost up on the inside?
2 Answers
The reason for frost forming on the inside of the windshield is due to significant differences in temperature and humidity between the inside and outside of the vehicle. Moisture on the interior glass solidifies into ice crystals, forming frost on the windshield. Methods to deal with frost on the inside of the windshield include: 1. Spraying anti-fog agents, which form a transparent protective film on the windshield; 2. Using the air conditioning's dehumidification function to reduce air humidity; 3. Using the air conditioning's warm air function to reduce temperature differences and eliminate frost on the windshield. Preventive measures for frost on the inside of the windshield include: 1. Applying soapy water, detergent, ethylene glycol, glycerin, or polyvinylpyrrolidone; 2. Coating the windshield with a carboxymethyl cellulose aqueous solution mixed with salt; 3. Applying a thick plastic film coated with silicone, followed by hydroxyethyl methacrylate silicone.
I've always found frost on the car windshield quite troublesome. This is a common phenomenon in cold weather, mainly caused by high humidity inside the car. Human breathing or accumulated moisture condenses into frost when it meets the cold glass. My usual approach is to start the vehicle a few minutes before driving and turn on the defrost mode of the air conditioning, usually set at around 25 degrees Celsius, with warm air directed toward the windshield. If frost forms, avoid wiping it with your hands to prevent scratching the glass; instead, use the external circulation mode to introduce fresh air and reduce humidity. I've also noticed that if the car's seals are aging, moisture can easily seep in, so I regularly check the window seals and leave a small gap for ventilation when parked to prevent moisture buildup. Safety should never be overlooked—frost can obstruct visibility, so always ensure a clear view before driving. In daily maintenance, cleaning the glass surface can reduce oil and dirt that attract moisture, and I always use a soft cloth for gentle wiping. Additionally, during winter trips, try to avoid bringing wet items into the car, such as umbrellas or damp clothes. In short, these small habits make my driving experience much safer.
