How can you keep the inside of your vehicle's windows clear after you have cleared them in humidity or rainy conditions?

How can you keep the inside of your vehicle's windows clear after you have cleared them in humidity or rainy conditions?

• A. Roll down the windows
• B. Turn on the heater only
• C. Wipe with a towel only
• D. Use the defroster or air conditioner

Answer: (D)

Fog on the inside happens when moist cabin air meets cooler glass. To keep the windows clear, you need to dry the air and warm the glass. The defroster or air conditioner does this: the defroster blows warm air onto the windshield to raise its temperature and reduce condensation, while the air conditioner dries the cabin air to lower humidity. Using just the heater won’t remove moisture, and wiping with a towel only clears a small amount of surface fog for a moment. Rolling down the windows can exchange humid air with outside air, but it doesn’t reliably dry the interior, so the fog can return.

Fog on the inside happens when moist cabin air meets cooler glass. To keep the windows clear, you need to dry the air and warm the glass. The defroster or air conditioner does this: the defroster blows warm air onto the windshield to raise its temperature and reduce condensation, while the air conditioner dries the cabin air to lower humidity. Using just the heater won’t remove moisture, and wiping with a towel only clears a small amount of surface fog for a moment. Rolling down the windows can exchange humid air with outside air, but it doesn’t reliably dry the interior, so the fog can return.