Winter mornings can be a nightmare for parents taking their kids to school. The car windows misting up seems inevitable and can be a time-consuming ordeal. In my experience, I have often found myself spending over ten minutes trying to clear the foggy windscreen, a task that is even more difficult when the children are in the car. Then to make it worse, the moment I set off, the windows instantly fog up again, making it necessary to pull over and spend another five minutes clearing them. So, the question begs: why is the car window fogging up inside?
Why is my car window fogging up inside?
If you want to know how to stop car windows from fogging up in winter, this simple explanation should help you understand why removing fog from your windshield is so tricky in the mornings.
- On cold days, your breath may form a visible haze or fog up a window. This occurs due to the amount of moisture present in each breath.
- Breathing in an enclosed space, such as a car, heats up the air and increases the humidity, causing moisture to accumulate in the environment.
- Moisture in the air arises from swimming bags, wet footwear, or even a hot cup of coffee. Cranking up the car heater under these circumstances makes fogged-up windows inevitable. Since the inside of the car has a different temperature from the outside, it creates the perfect setting for moisture build-up that causes the foggy window fiasco.
- When warm and humid air touches your cold windscreen, it causes the glass to fog up as the humidity condenses into moisture. Similarly, moisture in the air inside the car on a chilly day turns into condensation upon contact with the windows.
To find out more about how condensation is formed, read this article
Common causes of the excess moisture inside the car.
- Driver and passenger’s breath
- Sweat and heat from the driver and passenger’s bodies.
- Wet items like umbrellas, gym kits, or dog towels left in the car overnight
- Damp Floor mats from snow or rain on shoes and boots
- Open hot drinks such as coffee, tea, or hot chocolate left in the car
- Open bottles such as cleaning products
- Spilled drinks such as soda or juice
- Wet bodies such as swimmers or pets
- Wet car seats from leaving a car window open
- A Leak drips inside the car causing wet carpet or upholstery.
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How to prevent car windows from fogging up
Driving with foggy windows is dangerous and illegal, so let’s see how to defog a windshield quickly to prevent a potentially dangerous situation.
- Try to reduce the moisture level inside the car by changing the air and allowing the cold, dry air inside.
- Adjust the temperature of the windows inside the vehicle to match the outside temperature.
- Wipe the window with a paper towel or glass cloth like this one, or you can buy a special demisting pad like this one.
- Turn your air conditioner on full and direct the vents to the windscreen. This will help to dry out the air. Your air conditioner cools and dehumidifies your car. When you dehumidify the air, you eliminate the moisture that makes your car windows fog up.
- Remove frost from your windscreen with a de-icer and a scraper to help adjust the temperature.
- Warm your engine up for a while before you turn your heaters on.
- Should the air be hot or cold? I found that the screen clears quicker with cold crisp air; not great in the cold weather when the kids are freezing, but it works! Once the windows dry, you can give in to the cries and whack the heating up!
- Your windscreen and windows will probably not be fogged up when you first get into the car, but when you turn on the ignition, air blows onto the cold windows, and they start to mist up, so patience is the key to getting away quickly.
- If you come in from the rain and your clothes are wet, open your windows to let the moisture out and dry air in.
- Clean your windows with vinegar and water to keep them film-free. Moisture attaches to dirt particles on the windows, so keeping them clean with vinegar helps prevent car windows from fogging. Vinegar solution is the best window cleaner to use for inside windows as it doesn’t leave smears, especially if you use a glass cloth like this one to polish the glass. Also, don’t forget the rear windows. You can’t set off if you can’t see out of all your windows!
- If you haven’t got air conditioning in your car, you could try one of these portable demisters that sit on your car dashboard and helps to dry the windshield.
- Do not use the air recirculation setting, as this will recycle the damp, moist air around the car instead of getting rid of it. It is better to change the air rather than recycle it!
- Use a reusable dehumidifier like this one which sits on your dashboard and sucks the moisture out of the air. When the blue dot turns pink, it means it is full, and you pop it in the microwave for a few seconds to dry it out. The pink dot will return to blue and be ready to use again.
- Try not to leave damp items in the car overnight. While cleaning daily, I stored all my cleaning products in the car, contributing to my car window fogging up each morning. Keeping damp sports kits, umbrellas, damp clothes, or doggy towels in the car may mean you have a car window fogging up in the morning to contend with!
- Fill a pair of tights with clean cat litter and put them in the car. The cat litter will draw extra moisture from the air.
- Check for any leaks that may be making the car interior wet.
- Shake umbrellas and pop them in a sealed bag until you get home.
- Apply an anti-fogging coating like this one and apply it after cleaning the interior of the windscreen and windows.
- Ensure you remove as much snow from your shoes before stepping in the car to keep car mats dry.
- Air out your car, and leave the car windows open for a few hours on a sunny day to let the moisture escape.
- Rub shaving foam into your windscreen and windows, then wipe it down with a glass cloth. This apparently stops the water from beading and fogging up the windscreen.
This is an easy one! To defog windows when you have no heating in the car, reduce the number of damp items you leave in the car. And crack open the windows to change the air to fresh! Or use a portable screen demister like this one!
You may find that you have left some residual moisture in it even though you are not in the car overnight. This may be from the rain tracked into your mats and carpets or a cup of coffee in your car. It’s a good idea to keep track of the times that your car has foggy windows while parked, just in case it may have sprung a leak somewhere!
Sometimes the opposite happens on a hot, humid day if the air outside is muggy. The air inside becomes condensation when your air conditioner cools it.
It’s probably due to the excess moisture you are bringing into the car in the way of wet shoes or boots, wet coats or clothing, a wet umbrella, wet hair, or perhaps even a wet dog! The more wet people with damp belongings you have in your car, the more moisture you’ll bring into the air and the longer it will take to defog the windshield!
Is your car window fogging up inside? Shoot us your questions in the comments below!