’Tis the season for pumpkins, sweaters, and holiday fun. But with the changing weather comes the nemesis of many: foggy windshields. Fogged up windows can be super annoying, especially in the morning when you’re running late and your car isn’t warm yet. But more than anything, foggy windshields can be extremely dangerous for you and the drivers around you.
When you windshield is fogged up, it’s distracted and impairs your visibility on a roadway. If traffic suddenly stops, directs change, or speed limits shift, this lack of visibility can spell disaster, and even death. So how can you prevent fogged up windshields?
How Foggy Windshields Happen
Windshields fog up during cold weather primarily due to the difference in humidity between your car’s cabin and levels outside. When the humid air in your car meet the dry winter air pressing against the windshield outside, the result is condensation on the inside the glass. It’s comparable to how a glass of ice water condensates on the outside of the glass due to the disparity in humidity and moisture.
The biggest causes of foggy windshields are:
- Heat
- Humidity
- Condensation, and
- Surface tension
Defogging Foggy Windshields
We’ve already established that foggy windshields can spell disaster. Here are four tips to defogging foggy windshields.
- The first step that most people take that does the trick is turning up the heat. Most cars these days are equipped with vents directly under the windshield that can blow warmed air at the windshield. This method can help dry the air in the cabin and most specifically the air directly next to the windshield, helping to reduce humidity and condensation.
- While less ideal than turning on the heater, especially in col weather, another way to solve a foggy windshield is to crack the winds for a few minutes. This can help balance out the disparity between the air inside and outside, clearing the windshield in the process.
- Turning on the A/C is also a great way to remove moisture in the air. After turning up the heat, blast the air conditioning for a few minutes to further remove moisture from the air.
- Most modern cars are build with an air recirculation system that allows the A/C and heating system to recirculate the air that’s already in the car. This is a great feature when it comes to keeping pollutant or other airborne smells or particles out of the cabin. However, it can also eep moisture trapped in your vehicle cabin, since non of the air in the cabin is able to be replaced by air outside. Shut off your air recirculation after running your heater and A/C to replace the air in the cabin with outdoor air. This will bring your cabin to equilibrium with the outdoor air, thus, clearing your windshield.
Preventing Foggy Windshields
One of the best ways to keep your windshield from getting foggy is to take preventative measures. Here are just a few steps you can take to keep your windshield clear this winter season:
- Keep your glass clean. A clean windshield, wiped down with a microfiber towel and ammonia-free cleaner can go a long way towards keeping your windshield clear.
- After cleaning your windshield, apply a decreasing agent. Alcohol-cased surface cleaners tent to work best, as they strip oils away from surfaces.
- Most car part shops carry some line of anti-fog product. After cleaning and degreasing your glass, apply an anti-fog agent on the inside of the windshield. Buss the glass again with a dry microfiber cloth to finish.
For more auto tips and tricks, read more from our blog!
For for winter driving tips, check out the Washington State Department of Transportations tips here!