How to prevent and clear foggy car windows

There’s nothing more frustrating – or potentially dangerous – than trying to drive while your car’s windows are fogged up from the inside. Interior condensation is a common issue, particularly during cooler or humid months, and it can interfere with visibility, comfort and even vehicle safety. Fortunately, there are several effective techniques to prevent and remove fog from your windows by improving ventilation, reducing moisture and addressing underlying humidity issues.

It helps to get some clarity around why fogging happens within the cabin of a car. Fog on the inside of car windows occurs when moisture-laden air inside the cabin condenses on the cool surface of the glass. This often happens after overnight temperature drops, during wet weather or when passengers bring damp air inside the car (think wet shoes, jackets or pets). The solution lies in managing the moisture and airflow within the vehicle.

Ventilation: Let your car breathe

The first step to combating condensation is ensuring your car is properly ventilated. Do this by:

• Using your air conditioning system, even in winter (a low setting is fine). The AC helps dehumidify the air, which reduces the likelihood of condensation forming on windows.
• Setting the climate control to fresh air intake, not recirculate. Recirculating air traps moisture inside the car. Remember to turn it off when you drive through tunnels.
• Cracking a window slightly, if safe to do so, especially after rain or on humid days. This allows moist air to escape and dry air to enter.
• Turning on your rear window defogger and front demister. These built-in systems are designed to clear moisture quickly and efficiently. 

Moisture-absorbing products: Soak it up

Once moisture is in the air, the key is to beat it by absorbing it before it condenses. Here are some hacks to help soak up condensation.

• Silica gel packets, often found in shoe boxes or electronics, can be placed on the dashboard or under seats to passively absorb moisture.
• Dehumidifier bags or moisture absorbers designed specifically for cars are ideal for ongoing protection and can be refreshed or replaced regularly.

Addressing the root cause: Find the damp zone

If your car is regularly fogging up despite efforts to ventilate and dehumidify, there could be a deeper issue at play.

• Check for leaks. Wet floor mats or boot linings could indicate a leaking door seal, windscreen or air conditioning system.
• Dry out the cabin thoroughly. Remove floor mats and dry them separately. Use a portable fan or heater to air out the interior if needed.
• Keep the car clean. Dust and grime on glass can attract moisture and make fogging worse. Regularly clean interior windows with a dedicated glass cleaner.

3 prevention tips for crystal-clear drives

1. Don’t leave damp items in the car – wet umbrellas, gym bags or clothing add to the humidity.
2. Use an anti-fog spray on the inside of windows. These treatments form a thin film that resists condensation.
3. Keep cabin filters clean. A clogged filter can reduce airflow and worsen humidity.

By taking simple preventative steps and staying on top of moisture management, you can enjoy fog-free windows and safer drives, no matter the weather. A clear view isn’t just a comfort – it’s a necessity to staying safe on the roads!

_Disclaimer
^{Viva Energy Australia Pty Ltd (“Viva Energy”) has compiled the above article for your general information and to use as a general reference. Whilst all reasonable care has been taken by Viva Energy in compiling this article, Viva Energy does not warrant or represent that the information in the article is free from errors or omissions or is suitable for your intended use.}