Demystifying Windscreen Fogging

3 min read
At a loss as to what to do when your windscreen fogs up? Don’t be ‘blur’ — read on!

Fogging up of the windscreen occurs when condensation builds up as a result of the warm, humid air inside the car coming in contact with the cold material of the windscreen. The water vapour in the cabin air will turn liquid, resulting in tiny water droplets coating the windscreen, much like the moisture that forms on the side of a drinking glass filled with a cold liquid.

In cold weather
In places where snow and ice are the norm in certain parts of the year, windscreen fogging issues are more common. At those chilling temperatures, any little water vapour — from your body, your breath, and even that cup of hot chocolate in your cup holder — easily ends up on the windscreen and windows, and fogs them up. The kids may find it fun to draw on the windows in such situations, but not so much the driver — trying to negotiate traffic while your vision is impeded is not safe. And it gets worse if you are driving at night, as street lamps and other light sources will scatter from the condensation build-up — this kaleidoscopic effect impairs your sight further.

Most cars have a screen defogger/defroster button or have climate control, which simplifies defogging. With a screen defogger activated, the air conditioning comes on automatically, acting as a dehumidifier that clearsyour screens. If you’re driving halfway when your screen starts to fog up, leave the windows open for a few minutes to let some of the warm, humid air inside your car escape quickly, bringing in the colder, dryer air from outside. The idea is to clear the condensation as quickly as possible.

Reduce the moisture sources within the car by transferring any wet or moist items, such as a wet jacket, scarf or bag, to the boot. Then make sure the car is sufficiently warmed up so the defroster will work more effectively. Also,don’t let the air inside re-circulate as the moisture will never leave the cabin,making defogging the windows more difficult. Turn off the recirculating button and let fresh and drier air come into the cabin. This will assist in getting rid of condensation as well.

In humid weather
Back here in humid Singapore, there may be times the condensation appears on the outside because the humid outside air condenses on the outer layer of the windscreen due to the cooling effect of the air conditioning blasting away on the inside. If you have not been cleaning your car regularly, the grime and dirt on the exterior surface maysmudge the screen when you use the wipers to clear the screen. Dirt and oil attract moisture, so it helps to clean the glass regularly.

You can also apply anti-fogging coating products on both sides of the windshield and windows, as well as on your side-view mirrors. This leaves a thin film on the surfacethatprevents condensation from forming. Make sure surfaces are clean and dry before applying the product. Here’s a little less known life hack you can try: using shaving foam to clean the screens can help prevent fogging.

Make sure you use only recommended windscreen wipers, as cheap ones tend to fall apart or even damage your screens. An added tip is to use rubbing alcohol to clean the wiper’s blade edge. This will remove any soapy film or residue on the rubber, which may otherwise smudge your screen.