When you're in a rush on a frosty morning, the last thing you need is an icy car and 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 show you how to defrost a car windscreen quickly and safely.
Best way to defrost a car windscreen fast
1. Check your wipers
- Make sure your wipers aren't on before you switch the car on.
- If the wipers are frozen to the glass, the wiper motor could be damaged or the rubber could tear off if they start wiping.
2. Start the engine
- Start the engine and turn on the warm air blower to the windscreen.
- Switch on the rear window 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 from 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 – before you know it, that frozen windscreen will start to clear up. Make sure to use this spare time to clear the ice or snow from the outside of the car.
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.
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.
5. Get the all-clear
- Don't drive off until all of the glass is clear.
Car won't start in the cold? We'll come to your rescue.
Can you defrost a windscreen with warm water?
If you use hot water for the ice on your car, you run the real risk of damaging your windscreen.
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.
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 spilt 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.
Can you use cold water to defrost a windscreen?
We wouldn't recommend using cold water as it can freeze on the windscreen and cause damage. The best thing to do is follow the steps above on this page. Turn on the car heaters and the air-con, and use a proper brush or de-icer to scrape the frost of your frozen windscreen while you wait for the car to warm up.
Does hot or cold air defog windows?
The best way to defog windows is to use a combination of hot and cold air – as mentioned in our guide above. You should turn on your warm air blower and rear windscreen heater as well as your air-con. If possible, allow some outside air to come into the car as well. This should help you quickly turn a frosted over car back into something more drivable.
Don't fall for online "hacks"
There are 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. However, we wouldn't recommend trying this because the melted ice 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 and impair your ability to see the road clearly.
Driving safely means making sure that your line of vision is kept clear.
AA Patrol of the Year
Our 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 is on your side
Some new cars have remote heating technology – meaning you can heat up your car without even getting into it (and without risking theft by thieves).
Many manufacturers 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 a windscreen freezing 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 as close as possible to your home. The heat from your home 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".
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 taken 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.
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 windscreen. In fact, you can get a £100 fine and 3 points on your licence if you drive with obscured vision.
Avoid "portholing"
Not everyone bothers to clear all the ice off before they drive off, instead leaving just 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.
Ensure 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:
We provide 24/7 roadside assistance.
Why choose us for breakdown cover?
- We're a Which? recommended breakdown cover provider in 2023 – the sixth year running.
- UK drivers have consistently rated us as the best breakdown service against all other major breakdown providers.
- Our Patrols will usually get to you in less than an hour and get you back on the road within around 30 minutes of arrival.
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FAQs
Can hand sanitiser defrost a windscreen?
You can use a bit of hand sanitiser mixed with water to wipe your windscreen with a cloth, but it's not necessary when you can just turn on your car heater and air-con, which is a risk-free way of defrosting a windscreen.
Can you put a towel on your windscreen?
Putting a towel on your windscreen while you're not using your car could be a good way to stop it from frosting up. However, this won't work too well below a certain temperature (-10c), and it may not completely stop your windscreen from frosting over.
How can I defrost my windscreen quickly?
The quickest way to defrost your windscreen is to turn on the engine, the car heaters and the air-con. You can then stay with your car while it's heating up and use a brush or de-icer to manually remove frost from the outside of the windscreen.