How to demist your car effectively

By Adam White

As the nights draw in, average temperatures fall and the first mince pies appear in retailers, the need to demist your windscreen in the morning returns with a vengeance. This is, of course, vital in ensuring that your windscreen provides you with an unimpeded view of the road ahead. Remember, driving with impeded vision is against the law, not to mention dangerous.

Car Demist

Why does the windscreen fog up?

Generally speaking, a windscreen will become misted over when your windows are cooler than the temperature at which dew forms and your body warms up the air inside the cabin sufficiently. Your breath also helps by increasing the amount of moisture within the vehicle, which then is cooled and condenses when it comes into contact with your windscreen, causing the annoying and potentially dangerous mist.

How to demist the windscreen

According to the RAC, there is a four-step process for keeping your windscreen clear of mist on these cooler mornings. Firstly, your heater should start off on a fairly cold setting, directing all vents towards the windows and your windscreen. The temperature should be slowly increased as you go.
Putting the heating on full to begin with overloads the cabin with air that is both too hot and too wet to make a difference to the level of condensation. Once you begin to push the temperature up, the heat will both evaporate the mist, whilst warming up the windscreen to help reduce the chance of it returning.

Turning on your air conditioning can help to keep the air inside the car dry, reducing the risk of further mist forming. Use the air-con with your heater to attack the mist from two angles. If your vehicle is not air-conditioned, roll down a couple of windows, to attempt to equalise the temperature inside the car with the outside, whilst mitigating against the effect of your breath.

Once the mist has departed, you can warm the car gradually to a comfortable level. Finally, if your car has a demisting setting on your heating, using it should take most of the thought out of the demisting process.

Take a tip from top Ice Hockey stars

Ice hockey players have been known to use shaving foam to stop their visors fogging up whilst playing on the ice. Using shaving foam to clean the windscreen creates a protective barrier over the glass which makes it harder for mist to form, no matter what the temperature. Whilst this will not cure the problem permanently and needs to be repeated periodically, it has been shown to help.
To clean your windscreen using shaving foam, simply put a liberal amount onto a clean towel and spread across the surface. Using another towel, wipe the shaving foam off until the windscreen is completely clear. The protection will need to be reapplied as necessary in order to keep your windscreen clear.
To help protect your car for the winter ahead, why not book a free vehicle check online with our tyre professionals. Whether you need replacement tyres from brands such as Bridgestone and Pirelli in readiness for harsh driving conditions or you need advice on a wide range of other motoring issues such as heating and demisting, we're here to help.

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About the author

Article Author Photo
By Adam White
Adam looks to create engaging and informative content across the website that provides consumers with expert advice on MOTs, servicing, vehicle maintenance and tyre care. As a motorsport enthusiast, Adam enjoys documenting the Protyre Motorsport team’s involvement in major motorsport events across the UK.
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