Nothing’s worse than a foggy windshield in the midst of a hard rain or snow storm. It’s not always easy to pull over to avoid this safety hazard. A few simple steps will keep your windows clear and clean.
One common cause of foggy windows: when the temperature inside your car is different from the temperature outside your car. This temperature differential can cause water droplets to form on the inside surface of your windows or windshield (think of it as the opposite of evaporation). If you reduce the temperature difference, this condensation will go away. If it’s cold outside, warm up your car and its windows by turning on the heat and the defroster. If it’s a scorcher, then use your car’s air conditioning to reduce humidity, getting rid of water in the air.
Another easy fix involves the recirculate function of your heating/cooling system. Your car gives you the option of recirculating air inside the car or using fresh air from outside the car. If you’ve got frequent fog, then switch the setting to use fresh air. Otherwise you may just end up using the same moist air over and over – kind of like trying to rinse your hair in the same water you used to wash it.
Dirt and other build-up on the inside of the windshield is another common cause of foggy glass. Make sure you keep your car’s interior clean. Everyone has their own favorite way to clean their windshield; some prefer an ammonia-based cleaner, others swear by shaving cream (wipe on with a towel, then wipe off with another). Special auto glass cleaners are a good choice as these are made to leave a coating on the glass that will resist fog.
Finally, because moisture is the culprit when it comes to steamy windows, avoid bringing wet or damp items into the car, as this can raise the humidity level. Leave damp beach towels in the trunk and shake off as much water as you can if you’ve got an umbrella.
If you’re still noticing problems with fogged windows, you may want to get your car’s HVAC system checked or inspect your windshield to make sure there are no cracks or other damage that could be causing the problem.