How to demist your car windscreen quickly and safely | RAC Drive (2024)

Demisting your windscreenis a necessitybefore setting off, not doing so canimpede your vision while driving which means you will be driving illegally.

The cause of your car windscreen misting up is actually down to water vapour in the atmospherethat occurs when your body heats the air inside the cabin – as does your breath – increasing the amount of moisture it can hold.

This means when it comes into contact with your windscreen it cools and condenses, forming a 'mist' that can make winter driving a challenge.

Here's how toclear your windscreen in double-quick time (with a helpful 'life hack' thrown in at the bottom, to help stop your windscreen misting up in the first place).

Start the heater off cold, then slowly increase the temperature as the air dries out, rather than overloading the cabin with hot, ‘wet’ air.

Try to find a temperature and humidity that’s comfortable but doesn’t mist up the cabin.

Make sure your heater'sblast is directed at the windscreen and the windows - the warmer air (even on cold the air will be warmer than the ice cold windscreen) will dry the glass a little through evaporation and begin to heat up the glass to stop the water vapour condensing on it again.

Of course, if you're not in a rush and your frozen bones need warmth then use the hot air to warm both you and the windscreen.

It may take a little longer to clear fully but you will at least be a little more comfortable -just don’t move off until all glass surfaces on your car are clear. It’s dangerous andillegal if visibility is impeded.

If your car has air conditioning make sure it is switched on.

Use the air-con in conjunction with the heater. Hot air will dry the glass a little through evaporation, but the air will then cool down and condense on the glass once more, so make sure the air-conis on to keep the atmosphere inside dry.

If yourwindscreen is iced over, then the heat is obviously more necessary. But in this instance you might want to scrape the outside of your windscreen clear first. It is important to keepyour windscreen clear in winter.

If you don’t have a clever climate control system, having the windows down could actually help clear the screen faster.

This helps because the dry, cold air from outside can help reduce the amount of water vapour inside the car, stopping the screen misting up.

Then you can begin towarm the car up gradually to a temperature that suits you after you have cleared the windscreen.

Of course, you should never pull away with your vision impaired, but if your windows start to mist up during driving this is also a worthwhile tactic, for those without air-con. If the misting clouds too much of your vision you should pull over where safe to do so and wait for your windows to clear.

Make sure you know the law around fog lights and safe driving in foggy conditionsbefore hitting the roads.

If you dohave a clever climate control system, utilise it.

There’ll most likely be a setting for demisting the windscreen, which will automatically adjust the ventilation system’s parameters to achieve the best results.

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• Top tips to keep your windscreen clear in winter

Keeping your windscreen clean will go a long way to stopping it misting up in the first place.

A handy tip to go the extra mile is to actually clean your windscreen with shaving foam.

This protective barrier won't last forever and may need to be repeated regularly, but a windscreen cleaned with shaving foam will be less likely to mist up.

It's a little trick ice hockey players use to stop their face masks from steaming up when they're on the ice.

How to clean your windscreen with shaving foam

Take a clean towel and place a dollop of shaving foam onto it.

Wipe the windscreen with the towel, spreading the shaving foam over the entire surface.

Then take another clean towel and wipe off the shaving foam completely.

This protective barrier should helpstop your windscreen from misting up, but it will need to be regularly reapplied to continue to work.

Another useful item to help demist your car is a demister pad. These can be purchased over at the RAC Shop.

Tips for driving in winter weather

• 

  How to reduce the chances of breaking down in cold weather

• 

  Driving in fog: when to use fog lights

• 

  Driving in the dark - tips on how to stay safe

• 

  How to drive safely in windy weather

• 

  Advice for driving in heavy rain and floods

• 

  What is aquaplaning and how to avoid it

• 

  Advice for safe driving on ice

• 

  A complete guide to driving safely in snow

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