How to de-ice your car windscreen in freezing conditions

De-icing a car windscreen
De-icing your car's windscreen is a practical necessity – and a legal responsibility  Credit: Katielee Arrowsmith/HEMEDIA

Frozen windscreens and the perils of ice and snow on the roads are most prevalent throughout the UK in January and February during the coldest months, although various gardeners' websites suggest that there's a risk of frost in most parts until late April.

Drivers are reminded that in these icy months, it's extremely important to properly clear the ice from your car before setting off. If you drive your car with ice covering your windscreen, you could be endangering yourself and others – as well as breaking the law.

The law

The Highway Code clearly states that "windows and windscreens MUST be kept clean and free of obstructions to vision". During the winter months, this is particularly relevant – you must clear the ice (or snow) from all of your windows, as well as both the front and rear screens, before driving. This also applies to condensation that forms inside the car.

You should also pay attention to other parts of the car. The Highway Code states that "lights, indicators, reflectors and number plates MUST be kept clear". Snow and ice could obscure your lights, so clear those too.

How should I de-ice my car?

The only things you should ever use to de-ice your car is an appropriate ice scraper and/or some de-icer liquid. Some drivers appear hell bent on destroying their credit cards by using them to clear ice, but that's not advisable for many reasons.

Make sure you have a can of de-icer available, and that it's at least a quarter full. Spray it on the windows and front and rear screens. Start at the top, allowing gravity to help out – the de-icing liquid will dribble down the glass, melting the ice as it goes. You'll need to use a scraper as well, as de-icer rarely does the whole job.

When scraping, use firm, broad strokes across all the glass. Remove all the scraped ice and snow, and ensure that the windscreen wipers are not frozen. Do not be tempted to just scrape the driver's-side part of the screen – the police will take a dim view of this strategy.

Never use boiling water to melt the ice on a car. While windscreens are certainly more resilient than they used to be, pouring hot liquid on to frozen glass is unlikely to have a positive effect. The same applies to door locks.

Some people suggest using vinegar instead of de-icer. There are no real benefits to this, while downsides include potentially damaging the glass and paintwork of your car, while also smelling of a chip shop. As with credit cards, avoid using store discount cards to scrape your windscreen – you'll only get 10% off.

Can I start the car and go back to bed?

The short answer is no. If your car's engine is running, you need to be "in control" of it. While the specifics of this requirement might be up for debate, it generally rules out you being in your house having breakfast while your car ticks over outside.

You could find yourself in trouble with the police if you leave a running car unattended. Worse still, you could find it stolen – leaving a car with the key in the ignition and the engine running makes it very tempting to thieves. You may find that your insurance company won't cover you if you leave the keys in the ignition and the doors unlocked, too.

It is possible to switch on the heater and wait for the car to de-ice itself while you sit inside, but this costs time and fuel and is possibly the least environmentally-friendly method.

We'd recommend a spray can of de-icer, a good scraper (ideally with an insulated glove-style grip) and a 10-minute head-start in the mornings whenever the mercury dips well below freezing.

Clearing your car of ice is an important safety check – as well as a legal requirement – that could make the difference between a safe journey and a crash.

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