Frosty car windows inside? Here's why and what to do

Have you ever found the windows of your car frozen from the inside? We're here to explain why it happens and how to swiftly eliminate any frost that builds up internally.

Windows freezing up from the inside is a natural occurrence typically experienced during severe frosty conditions. While driving, moisture builds up within the car cabin. This happens not only when moist air enters the cabin, but also when snow carried in on shoes starts to melt. As driving concludes and the car cabins remains warm and humid, this moisture settles on the windows and subsequently freezes.

The end result? The next day, you're faced with the task of a lengthy defrosting session using the ventilation system or scraping the ice off.. It's no easy chore, particularly with concave windshields. Outside, a good ice scraper works wonders, but from the inside, it becomes a bit difficult.

If you've wondered how best to remove frost from the inside of a window, your usual scraper might fall short. It is straight and rigid, making the task quite challenging and time-consuming.

Opting for chemical defrost isn't the most effective method either. Not only does it require a waiting period to kick into effect, but during this period, it drains down behind the dashboard. Additionally, it tends to emit an unpleasant odor, forcing you to air out the car or breathe it in.

I also tested a microfiber cloth. While a dry cloth does an okay job if you've got ample strength and patience, a damp cloth barely makes a difference. Even after it does melt the frost, ice is still left on the window, limiting visibility.

The best solution turned out to be a simple card! For instance, the points card you receive when refueling at a gas station doesn't just come free of cost, but you wouldn’t mind if it gets damaged, unlike your ATM or ID cards. But do exercise caution, as plastic cards can easily break.

Due to its flexibility, the card perfectly molds to the shape of the window, effectively removing frost and ice. Do note, however, that this method isn’t as efficient on the external surface of the window, especially when the ice layer is thick, as the card tends to be too soft.

If your car's ventilation system is functioning properly, the cabin filter is clean, and you use air conditioning regularly, you should not face this problem. In frosty conditions, even the seals won't pose an issue since the external humidity is virtually non-existent. Moisture builds up inside the car when the cabin is heated during the drive and then freezes. Therefore, the most effective solution is to eliminate this moisture before it settles on the window.

Seasoned drivers and those who regularly use their vehicle, such as families, often employ a simple method: ventilate the interior for a few seconds after each journey by opening all the doors. The moisture collected in the cabin will either freeze quickly and/or the car will be dried out by the low temperature.

Wondering what this has to do with families traveling? When, say, four family members are commuting together, it's likely they all exit the car simultaneously, each through their own door, after their journey ends. This causes all doors to be open for a short while, allowing proper ventilation. Often, the trunk is opened too, and this combined effort allows for the moisture to be effectively eradicated from the inside, preventing frost from forming on the windows.