With the colder winter air comes fogged, frosted, and iced-up windshields. As much as you want to get that glass cleared up as fast as possible, experts say using the “air recirculation” button in your car is a bad move. For those unfamiliar, that’s the button that has the arrow that looks like it’s making a U-turn on your car’s climate control panel. That feature sucks air from the outside and brings it into the car. It’s great when it's hot out, but the colder air can cause your windshield to fog up more…and keep it fogged up longer. Plus, the increased humidity in your car can make the inside of your car “stuffy,” which could cause drowsiness and put you at risk for a crash. You’re welcome.
Source: LAD Bible