How to defrost a car windscreen

Get a quick start on cold mornings with our tips

When you're in a rush on a frosty morning, the last thing you need is an iced-over windscreen.

But did you know that some methods of defrosting a windscreen could damage your car? Or even risk it being stolen?

Our simple steps can help clear your windscreen quickly and safely.

Best way to defrost a car windscreen

1. Check your wipers

  • Make sure your wipers aren't on before you switch the car on.
  • If wipers are frozen to the glass, the wiper motor could be damaged or the rubber could tear off if they start wiping.

Step 1 - switch off windscreen wipers

2. Switch on the engine

  • Start the engine and turn on the warm air blower on the windscreen.
  • Switch on the rear windscreen heater and heated mirrors, if you have them.
  • Turn on the air-con. It's not just for summer – it'll remove moisture from the air to stop the car misting up.
  • Don’t use your hands to wipe misted-up windows – you'll leave greasy smears and a diamond ring could scratch the glass. Use a lint-free absorbent cloth if necessary.
  • Stay with your car the whole time while the engine's running.

Step 2  - Switch on engine

3. Sweep off the snow

  • Clear all the snow off the car.
  • A soft brush is good for clearing the front grille (otherwise there is risk of the engine overheating).
  • Make sure lights are clean and working.

Step 3 - Sweep off the snow

4. Scrape while you wait

  • Use a scraper and de-icer on the outside of your car while you wait for the inside to warm up.

Step 4 - Scrape while you wait

5. Get the all-clear

  • Don't drive off until all of the glass is clear.

Step 5 - Clear your windscreen


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Don't land in hot water

If you use hot water on an iced-over car, you run the real risk of damaging your windscreen. Most people know not to use boiling water on their windscreen, with only 2% of people we asked saying they do this.*

But our survey found that young people (aged 18-24) are more than twice as likely to use boiling water as the general population. 1 in 20 risk a cracked windscreen by pouring boiling water on it.*

Avoid even lukewarm water

Glass expands quickly when hot or even warm water touches it. But it'll contract quickly too as it cools down in the cold air. That flexing can make the glass crack even if you're using lukewarm water – especially if it had small chips or cracks already.

When we asked drivers, 23% said they'd used warm water on the windscreen.* But the risk isn't worth it as it could land you in a worse situation than when you started.

Beware a refreeze

On very cold days, the water could turn to ice before you know it - and warm water freezes faster than cold water. If it refreezes, it'll create a layer of ice on your windscreen (and on your driveway if you've spilled any!)

Worse, it'll build up on the wipers and freeze them to the glass, risking damage to the wiper motor or ripping off the rubber if you switch them on.

Clearing snow off car windscreen

Don't fall for online "hacks"

There's a lot of videos out there claiming to have genius ways to defrost your car. But most of the methods don't work or could even cause you extra problems.

Hot water in a sandwich bag?

The internet was in meltdown when a driver shared his "hack" of putting hot water in a sandwich bag to defrost his windscreen. But when asked our Members, only 2% of them said they'd tried it.* It's just as well, because the melted water could refreeze and cause your windscreen wipers or even door handles to stick.

Half a potato on your windows?

Another hack suggests rubbing half a potato onto the inside of your windows to stop them steaming up. We wouldn't recommend rubbing anything onto your windows that could smear them.

Driving safely means making sure that your line of vision is kept clear.

Ben Sheridan, AA Patrol of the Year

Ben Sheridan, AA Patrol of the Year, says, "Driving safely means making sure that your line of vision is kept clear. If your vision's obscured, you might not be able to see the road ahead properly and it could even create a blind spot. Use a lint-free cloth to wipe condensation off windows without leaving smears."

Remember: tech's on your side

Some new cars have remote heating technology which can heat up your car without you you having to be in it (and without risking theft by thieves).

Manufacturers like Volvo, Jaguar, Land Rover and Ford offer remote heating and defrosting, with some letting you use an app to turn on the heaters.

Many plug-in hybrid vehicles and electric vehicles have a clever pre-heat function that heats the vehicle electrically while it’s plugged in. That means a toasty, frost-free car without running down the battery and reducing the car's electric range.

Learn what to do you if your car heater's not working properly

Stop frost in the first place

You can stop frost from forming in the first place with a little forward planning.

  • If you have a garage, use it in winter because it'll stop your car from getting iced-up.
  • If you don't have a garage, park your car on your driveway close to the house. The heat from your house can help to stop ice forming.
  • Put a shield across your windscreen to stop it getting icy - a piece of cardboard works well for this.

Keep your car safe from thieves

It can be tempting to leave the car to defrost while you retreat to the warmth of the house. But you're skating on thin ice if you do.

Thieves see frosty mornings as a Christmas gift, looking out for defrosting cars that have been left unattended with the engine on. The crime even has a name: "frosting".

Our research showed that almost 1 in 6 drivers (16%) leave their engines running and go back inside to wait for the ice to clear.

  • Scottish drivers seem to be the most trusting - almost a quarter (23%) leave their car with the engine running.*
  • Only 1 in 10 of people in London leave their car while it defrosts.*

Unfortunately, you'll get the cold shoulder from your car insurance company if your car's stolen that way. You won't be covered if it's nicked because you left your keys in it unattended.

To keep your car safe, wrap up warm and stay with it the whole time. If you need to go back indoors, switch off and lock the car.

Porthole cleared in icy windscreen

Finish up before driving off

If you're hurrying to get to work or do the school run, it can be tempting to drive off as soon as the ice has cleared a little.

But this could dangerously obstruct your view of the road if there's still ice or mist on your windshield. In fact, you can get a £100 fine and 3 points on your licence if you drive with obscured vision.

83% of drivers use a proper ice-scraper and 63% use de-icer. That's compared to 14% of people who risk a snapped bank card or scratched windscreen by using a credit or store card to scrape away the ice.*

Avoid "portholing"

Not everyone bothers to clear all the ice off before they drive off, instead leaving enough of a window to see through. This is known as 'portholing' and could get you in trouble with the police if you're caught driving dangerously.

Make sure your windows are clear and follow our tips for driving in snow and ice to keep safe.

Check off your list

In winter, we all know the importance of making a list and checking it twice. Our handy winter checklist is full of useful items to keep in your car so you'll be ready when the weather gets colder.

You might not know it, but the Highway Code has recommendations on how to avoid a winter breakdown. It says to make sure your car battery is well maintained and that you've got the right anti-freeze levels in your radiator and screen wash.

With a bit of forward-planning and TLC, your car should skate through winter without any problems.

Find out more:

*Based on 17,643 responses to an online Populus poll of AA Members between 10 and 17 December 2019.


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