It’s wet, it’s cold, and your windows are all fogged up. So you crank up your defroster and wait… and wait… but somehow the windows never seem to clear up.

If your car defroster isn’t working, chances are you have the defroster set wrong. Set the controls to allow for fresh air instead of recirculated air.

Foggy Car Windows Explained

Why would that matter? Because, when the system is set to recirculated air, it pulls the air from the floorboards. The drier air from the defroster never reaches the windows; it circulates back to the air ducts before it gets there.

When you change the setting to use fresh air, that dry, conditioned air blows out the ducts and works its way through the car and out the body vents. It reduces the humidity throughout the entire car… all the way to the windows.

Want to clear the windows even faster? Switch from defrost to A/C. The air conditioning ducts blow the dry air through the A/C vents, so you can direct that air right where you need it most. Adjust the temperature to keep it from getting too cold.

Vehicle Window Defroster

It also helps if your A/C system is working properly and is fully charged. That’s because nearly every car on the road today is designed to turn the A/C system on when you select the defroster. That A/C system condenses the moisture in the air, so the air coming through the defroster vents is a lot drier than the air outside. That drier air defrosts the windows faster.

But whether you use the A/C or defroster settings, the trick to getting your windows cleared is to set the system to fresh air; not recirculated.