What Causes Frosting on the Interior Windshield?
2 Answers
Frosting on the interior windshield occurs due to water vapor condensation. During driving, moisture in the air adheres to the windshield as the cabin temperature drops, leading to crystallization. Automotive glass is manufactured by heating the glass to near softening temperature in a furnace, then rapidly transferring it to air grids with varying cooling intensities for uneven cooling, creating different stress levels between the main viewing area and peripheral zones. Windshields are typically designed as large curved single-pane structures with specific curvatures on all sides. This curved glass represents a technically demanding product in terms of both manufacturing and assembly processes, as it involves considerations such as vehicle model compatibility, strength, thermal insulation, and installation requirements.
I remember one winter morning when I was driving to work, the inside of the windshield was covered in ice, making me late and causing a lot of trouble. The reason was that the temperature and humidity inside the car were too high. Human breathing and wet clothes left in the car release moisture, which condenses into water and then freezes when it meets the cold glass surface. If you don't open the windows to ventilate when parking, the moisture accumulates even more. When there's a big temperature difference, like overnight sub-zero temperatures, the warm interior makes the glass more prone to icing. Prevention is simple: open the windows for a few minutes before driving to let the air circulate, or wipe the inside of the glass with a towel. Don't pour hot water on it abruptly, as it may crack—it's better to start the car and use the heater to slowly melt the ice. Regularly check the window seals to prevent water from seeping in and worsening the problem. These small habits can save time and avoid unnecessary hassle.
