Why Does the Windshield Fog Up When the Heater is On?

[EliAnn]

Fogging on the windshield when the heater is on is mainly caused by the temperature difference between the inside and outside of the car. Due to the warm interior and cold exterior, water vapor condenses on the cold glass, forming fog in a short time. Solutions for fogging on the inside of the car windshield: Open the windows for convection. When the fog is not too heavy, you can open a crack in the windows on both sides to allow outside air to circulate, reducing the temperature difference and removing the fog. Press the defrost button on the center console to adjust the air vents to direct airflow toward the windshield. Spray anti-fog solution evenly onto a soft cloth and wipe the windshield, or spray it directly onto the glass. Methods to prevent fogging on the car windshield: Applying a plastic film to the windshield can isolate the glass from direct contact with cold air, reducing the condensation of water vapor on the glass.