Should You Use Hot or Cold Air to Defrost the Windshield on Rainy Days?

[HannahMarie]

Using cold air to defog the windshield on rainy days is generally faster. When cold air is blown onto the glass, the fog quickly dissipates, providing a rapid and direct effect. This happens because the cold air creates a "cold air film" on the glass surface, preventing carbon dioxide from condensing on the glass and thus achieving the defogging effect. Below are some methods for defogging car windows: 1. Apply Anti-Fog Spray: Spray a small amount of defogging agent onto the car window and wipe it clean. This removes dirt and stains while forming a thin, transparent protective film on the glass, effectively preventing moisture from condensing and forming fog. 2. Air Conditioning Cooling: Use the air conditioning's cooling and dehumidifying function to reduce air humidity and remove fog. In summer, especially when many people enter the car without turning on the air conditioning promptly, the exhaled humid air can quickly cause the windshield to fog up. In this case, turn on the air conditioning and direct cold air toward the windshield. The dehumidifying function will quickly remove the fog.