How to defrost your car windscreen quickly and safely

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Winter weather
Mistakes to avoid
How to avoid it

We’ve all been there. You’re running late for work, everything is going wrong… and then you get outside to your car and are faced with the jarring sight of the windscreen covered in a layer of ice. Nightmare!

As the days grow shorter and winter creeps closer, not only do car owners have to cope with driving in ice and snow, but the much-hated task of defrosting your windscreen becomes an essential addition to your daily schedule.

While it's tempting to leave the engine running with the heater on and head back into the warmth, this could actually land you a £1,000 fine and leave you at risk of theft. There is an easier, simpler way - check it out below, along with some tips on what to avoid, and how to prevent ice or frost developing in the first place 👇

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How to defrost your car - step-by-step

Whether you’re off on a winter road trip, driving home for Christmas, or just commuting, defrosting your car is important. Not only is it safe - you should never hit the road if your vision is obstructed - but not doing so could leave you with a fixed penalty. So make sure you’ve cleared your windscreen before you get going.

Start your engine

Begin by checking that your windscreen wipers are switched off - if they are frozen to the glass when they start wiping, the rubber or motor could be damaged.

Start the engine and turn your heater to its highest setting, which helps warm the inside of the car and start the defrosting process. If you have a rear window heater and heated mirrors, turn them on too, and use your air-con to remove moisture from the air, preventing the car from misting up. (PS - we’ve also got a guide about demisting the inside of your car windscreen, if that’s what you’re looking for.)

Never leave your car unattended while it's running, especially with the keys inside, as many vehicles are stolen in this situation.

Deicing your car can be a pain on chilly mornings
Deicing your car can be a pain on chilly mornings

Use a de-icer spray

While the car is warming up, you can apply a commercial de-icer spray to the outside of the windscreen to help soften the ice, brushing off any snow first.

Remember to keep ready-made de-icer spray away from any pets; it can cause irritation, chemical burns, gastrointestinal problems, and, in extreme cases, severe kidney damage, which could prove fatal.

Scrape the ice

With the de-icer working its magic, use a plastic scraper to remove the ice from the windscreen gently. Start from the edges and work your way towards the centre.

Never use a metal scraper, which can leave scratches on the glass.

Wipe away residue

Once the ice has been removed, use your windscreen wipers and washer fluid to clear away any leftover ice shavings or de-icer residue.

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Mistakes to avoid when deicing your car

We’ve all heard about those ‘hacks’ to deice your windscreen quicker. But some don’t work, and some could even damage your car. Here’s what to avoid.

Hot water

When hot or warm water comes into contact with car windows, the glass rapidly expands and then contracts as it cools in the chilly air. This sudden change can cause the glass to fracture, particularly if there are any pre-existing minor chips or cracks.

As well as that, in extremely cold temperatures, hot water can freeze quicker than cold water due to a phenomenon known as the Mpemba effect. Therefore, using hot water to defrost your car's windscreen could result in the water freezing more quickly.


Portholing is when you drive away after clearing only a small patch on the windscreen to see through. It’s dangerous and illegal, and could result in a fine or points on your licence. So, make sure you’ve got a clear view out of all your windows before you drive off.

DIY deicing sprays

There are all sorts of recipes for make-at-home deicing sprays, but it’s best to stick to those found in shops and garages. Some can damage your paintwork or windscreen.

Leaving your car unattended

The temptation to leave your car as it defrosts while you stay cosy inside is understandable, but it leaves you vulnerable to car thieves.

This scenario, commonly known as "frosting," presents an ideal situation for opportunistic thieves, and if your vehicle is stolen because the keys were left in it, your insurance policy is unlikely to cover the loss.

It’s also illegal. Leaving the engine running while your car is parked on the public road is an offence under regulations 98 and 107 of the Road Vehicles (Construction and Use) Regulations 1986, reinforcing rule 123 of the Highway Code. And as a cherry on the cake, an idling engine produces up to double the pollution as an engine in motion.

Consequently, it's best to bundle up and stay with your vehicle while it defrosts. Turn off the engine and lock your car if you must return inside. This minor inconvenience is a necessary step for the safety of your vehicle.

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How to prevent your car freezing up

You can reduce the likelihood of your car icing over at all with some quick and easy precautions.

Use a windscreen cover

A windscreen cover is the simplest method to avoid frost buildup on your car's windscreen. By shielding the glass, the cover collects the frost, meaning you'll find your windscreen ice-free when you remove it on a chilly winter morning. These covers are available from many retailers, or you can make your own - especially useful if a sudden temperature drop catches you out.

For a DIY approach, a piece of thick cardboard works well. Avoid materials like newspaper, as they tend to absorb moisture and can freeze onto the windscreen, creating an additional hassle. It's best to apply the windscreen cover in the evening, before the night-time freeze

Don’t forget to cover your wing mirrors too. You can pop plastic bags over them, held on with elastic bands. .

Use pre-icer spray overnight

Sometimes called ‘night-before de-icer’, use pre-icer spray on your windscreen on cold, frosty nights to prevent ice from forming on the glass. If any frost develops, the spray stops sticking, making it easy to clear in the morning.

Park facing east

While this may not help drivers who leave before the sun has risen in the morning, park facing east so that the rising sun defrosts your windows naturally.

As winter's chill sets in, mastering the art of efficiently defrosting your car becomes crucial. While it might seem like a small part of your daily routine, taking the right approach can save you time and enhance your safety on the road.

Equipping yourself with tools and knowledge can help you face frosty mornings with confidence. So, next time the mercury dips, embrace these de-icing strategies and ensure your winter journeys start smoothly and safely.

As well as deicing your car, you’ll also need to make sure you’re insured before hitting the road. With Cuvva, you can borrow any car with just a few taps on the app. It only takes a few minutes to get a quote.

Updated on 4th December 2023