Your car windows keep fogging up inside. It's inconvenient and annoying, as well as hazardous, if moisture buildup blocks your view. Window condensation is a common problem in cold weather when people inside the car are talking, and in warm, humid weather when the windows are closed. Steam also develops on the exterior of the windows when a car has been parked in a garage that remained cool overnight while the outside air was warm and damp. There are several methods that lessen the tendency of car windows to create condensation and retain moisture.
Clean the windows with a good-quality window cleaner. Dirty windows retain more moisture. You also can use a mixture of vinegar and water, or ammonia and water, sprayed onto the window and wiped away. Avoid soap, because soap residue attracts dirt, which causes condensation buildup. Wipe away the solution with a cloth that won't leave any residue, such as an old pillowcase.
Pour salt onto a cotton or cotton/polyester cloth and create a bag from the cloth, fastening it at the top with a rubber band. Rub the cloth over the interior windows. Repeat every few weeks.
Remove paper items from the car. You may want to have a map or two, but paper holds moisture. Think of how limp paper can become in humid weather. Telephone books, mail, newspapers and cardboard boxes attract moisture from the air, which eventually gets transferred to the windows.
Use glass treatment products such as Rain-X for exterior windows. These solutions repel moisture droplets from rain, sleet and snow, improving visibility.
Keep air flowing in from the outside with the fan, whether you're running the heater or the air conditioner. If the car becomes too warm or too cool, keep the fan running and use the temperature setting to make the car more comfortable. The fan may be a little noisy, but bringing in more outside air stops the windows from steaming up.
Run the defroster and direct air from the vents toward the side windows.
Keep a cotton cloth, microfiber fabric or clean blackboard eraser in the glove box to wipe windows off if they do develop condensation. Using your hands leaves oil on the windows, which can worsen the condensation problem in the future. Paper towels or napkins can leave paper fiber residue that will attract moisture.
