How to clear foggy windows

NRMA how to clear foggy windows
foggy windows

Is winter motoring blurring your vision? We’ve got some tips that will help you clear the air.

Air trapped in a vehicle is usually warmer and more humid than the cold air outside. Windows and windscreens are usually cool from the outside temperatures so, as the warmer air gets in contact with the cool glass, the inside air temperature drops and so does its capacity to hold moisture. This results in water vapour (fog) on the inside of the windscreen and windows. That all happens when there’s nobody in the vehicle, so when people are inside the car, breath and body temperature further increases the humidity.

The good news is that the remedies for steamy windows are straightforward and your car is fitted with a number of features aimed at keeping your vision clear.

Air conditioning

If your windows are ‘fogging up’, try leaving the air conditioning switched on with your heater set at a comfortable temperature. You’ll be surprised how quickly the fog clears. It’s also a good idea to turn the re-circulation off when using the air-conditioning and allowing a little fresh air in when possible. Funnily enough, using your car’s demister function is an often overlooked way to clear the windscreen of condensation. In most modern cars the demister will engage the air-conditioner and the fan to force dry warmed air on to the windscreen.


In addition to the front windscreen demister, your car is also equipped with a rear window defroster. To keep the glass clear of condensation, the defroster uses an electric element to warm the glass sufficient to evaporate accumulated moisture. It’s a system that works as effectively as your windscreen’s defroster.

Keep it clean

The oil, dust and other contaminants that build up on your windows gives water vapour more surface area on which to hold. A good car windscreen polish is the best way to clean the windscreen and help reduce the effects of condensation. Clean glass reduces the amount of area these tiny droplets love, meaning your car’s glass will take longer to steam up in the first instance, and be quicker to clear with the methods above once foggy.

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