I don’t know about you, but every winter, I get in my car to take the kids to school, and bam, the windscreens have misted up, and it takes what seems like hours to clear. It’s even worse if the kids are in the car whilst I clear the ice from the outside. I’ve often sat in my car for over ten minutes (not good on the school run), eventually managing to get the windows clear, only to find that the second I hit the road, they’ve fogged up again, forcing me to pull over and wait for another five minutes. So, how can we stop a car window fogging up inside? Let’s find out why they fog up in the first place!
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 it’s so difficult to remove fog from your windshield and get going on a winter morning!
- When you breathe out on a cold day and see your breath or you breathe on a window in the winter, and it fogs up this is due to the volume of moisture in each breath.
- When you breathe into an enclosed space like a car, you heat the air and add moisture to the environment.
- If you’ve been swimming, have wet shoes, or have a cup of steaming hot coffee then this will add even more moisture into the air. If you then put the car heating on, you’re creating the perfect conditions for foggy windows, as the temperature outside the car is different from the temperature inside the car.
- A car window fogs up when humid or moist air touches something cold like your windscreen. That humidity condenses and leaves moisture behind forming fog. On a cold day, any moisture in the air inside your car turns to condensation when it hits the windows.
To find out more about how condensation is formed, read this article
Common causes of excess moisture inside the car.
- Driver and passenger’s breath
- Sweat and heat from driver and passenger’s body.
- Wet items like umbrellas, gym kit, 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.
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 get rid of 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? Is the question I’m asked all the time. 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 start to dry, you can give in to the cries and whack the heating up! Using the car’s air conditioner and heater properly will help you get to drive away quicker. 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 the dry air in.
- Clean your windows with a vinegar and water solution to keep them clean and film-free. Moisture attaches to dirt particles on the windows, so keeping them clean with vinegar solution helps to prevent car windows from fogging up. 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 don’t have air conditioning or climate control in your car, open the windows and let in the fresh air even when it is cold outside. It may take a little bit longer to remove windshield fog than it would if you had air conditioning, but it works just as well. Rolling down your windows and bringing the temperature of your windscreen closer to the temperature outside of your car will get rid of most of the fogging.
- 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 recycling 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 that it is full, and you pop it in the microwave for a few seconds to dry it out, the pink dot will then return to blue, and it will be ready to use again.
- Try not to leave damp items in the car overnight. When I was cleaning every day, I used to store 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 that you have a car window fogging up problem 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 the 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, leave the car windows open for a few hours on a sunny day to let the moisture escape.
- Using the air conditioner and heater will help you clear the foggy windscreen quickly. Your windscreen and windows will probably not be fogged up when you get in the car, but when you turn on the ignition, air starts blowing on the cold windows, and they start to mist up.
- 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 even a cup of coffee left 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.
Is your car window fogging up inside when it rains? 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 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!