How to defrost a car: the quickest way to deice and demist your car windscreen - how to stop it freezing over

How to defrost a car windscreen quickly using air con, scrapers and de-icer, how to stop your windows icing up and why ice forms on the inside of the glass

An iced-over windscreen is one of those things that most UK drivers have to face at this time of year.

The combination of regular wet weather and falling temperatures mean that all over the country motorists will inevitably be faced with a layer of ice covering their car’s glass. Although it can be tempting just to clear the bare minimum so you can get going, doing so is not only dangerous but also illegal, so it’s far better to do a proper job from the start. Social media is awash with ridiculous ways to clear snow and ice from your car but here are some simple tried and tested methods for quickly de-icing your car’s glass.

Power up and use air con

Heating your car will help clear ice from the windscreen more quickly, so start the engine and get the ventilation working in your favour. Make sure your wipers are turned off before you start the engine. Activating them when they’re frozen to the glass could damage the blades or motor. Use your heated rear windscreen and, if you’re lucky enough to have them, make sure your heated mirrors and front screen are activated as well.

Set your heating to blow warm air onto the windows to heat the glass from inside. Don’t use air recirculation as this will trap damp air in the car and cause condensation. Instead draw fresh air from outside and, if you have it, make sure your air conditioning is switched on. Air con doesn’t just cool the car in summer, it helps to remove moisture from the air in winter. This will prevent your windows from fogging up as you clear the outside ice.

Pre-heat your EV

Most electric cars and many plug-in hybrids have a pre-heat or pre-conditioning function that is perfect for winter mornings. The function allows you set your preferred temperature and have the car pre-warm the interior for a certain time each day. Not only does it make the car cosy for the start of your journey but it should defrost the glass too. Just remember that if the car isn’t plugged in, this will eat into your battery reserves.

Clear loose snow

If it has snowed, use a soft brush or similar to clear loose snow from the glass, lights, number plate and body panels. Removing snow from the window will help melt the ice quicker, while removing it from everywhere else will help you comply with laws about visibility and causing a hazard to other drivers.

Use the right tools

When you’re in a rush it is tempting to use whatever is closest to hand to clear your windscreen. Credit cards and CD cases are old favourites but are nowhere as effective as a proper ice scraper. They don’t work as well as a purpose-made scraper and also run a risk of breaking in your hand or even scratching the glass. Using your bare hands is also ill-advised as any rings or other jewellery have the potential to damage the glass. The same goes for clearing ice or condensation from the inside of the screen. Use a microfibre cloth rather than your bare hands as this will avoid damaging the glass or creating streaks that could affect your vision.

Use a spray

De-icer sprays are a very quick way to cut through windscreen frost but that’s because they’re full of chemicals that aren’t particularly good for your car’s paintwork or the environment. Pre-made ones are handy if you’re in a hurry but you can also make up your own by mixing one part water to two parts rubbing alcohol or white vinegar.

Don’t use hot water

It really shouldn’t need repeated but don’t ever feel tempted to just chuck a load of hot water over your car windows. The sudden shock change in temperature could crack or shatter the glass, especially if there’s an existing scratch or chip. Even if that doesn’t happen, if the temperature is particularly low the extra water could just freeze again, creating even more work for you.

How to stop a car windscreen from icing up

Prevention is better than cure, so better than any of these solutions is to prevent your car’s windows from frosting up in the first place. The best way is to keep your car well sheltered from the weather. A garage is obviously the best option but even a carport or other external shelter will offer some protection from the worst of the weather. and mean that, even if you still have to de-ice your car, it should be a little easier.

If that’s not an option, use a windscreen cover. You can buy purpose-made ones that will sit snugly over your windscreen or you can make one. A large towel, blanket or even sheet of cardboard will do, soaked in salt water and held in place by the windscreen wipers. Newspaper shouldn’t be used as it’s too thin and will simply stick to the glass.

You can also spray your windscreen with the de-icing water/alcohol solution in the evening, which should help prevent ice from forming on the glass.