How to defrost your car

Unless your car’s protected from the elements in a garage, chances are you’ve scraped a few icy windscreens in your time. Here are some tips for swift, effective de-icing, so you can start your journey frost-free.

Unless your car’s protected from the elements in a garage, chances are you’ve scraped a few icy windscreens in your time. Here are some tips for swift, effective de-icing, so you can start your journey frost-free.

Rory Reid
Car and technology expert
4
minute read
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Last Updated 2 SEPTEMBER 2022

How do I de-ice a car?

On a freezing morning, you’ll want to de-ice your car as quickly as possible so that you can get back into the warmth. But it’s vital you do it properly to ensure you:

  • Don’t damage your car
  • Have enough visibility to drive safely 
  • Comply with the law.

Here’s our step-by-step guide to making sure your car’s roadworthy on frosty mornings. 

1. Plan ahead

Check the weather report the night before. If you know it’ll be a cold morning then you know you’ll have some defrosting to do. A little forward planning could save you a lot of time.

2. Allow plenty of time

Ensure you leave enough time to do a proper job. It could take up to 10 minutes to de-ice a car properly, so it might mean leaving the house a few minutes earlier.

3. Check your wiper blades and start your engine

It’s possible that your wiper blades may have frozen to the windscreen, so make sure they’re free before you switch anything on. Consider leaving the wipers in the up position (not touching the windscreen) overnight. Once you’ve done that:

  • Switch on the engine
  • Turn on the heater and set it to blow on the windscreen.
  • Turn on the rear windscreen heater
  • Leave the engine running while the heaters begin to take effect. But do not, under any circumstances, leave your car unattended without switching off the engine and locking it – you don’t want to fall victim to an opportunistic thief. 

Some new cars – particularly electric vehicles - may allow you to switch on the heating with a smart phone app from the comfort of your home or pre-program the heating so it comes on automatically every morning.

4. Sweep the snow off your car

  • Use a soft brush to sweep any snow off your car. If you leave snow on the roof it could fall onto the windscreen as you drive, blocking your visibility. Snow from the bonnet could also blow upwards. 
  • Clear the front grille to prevent your engine overheating.
  • Make sure your lights and indicators are clear and are all working.
  • Ensure your number plate isn’t obscured. 

5. Start scraping while your vehicle warms up

Use a good-quality scraper, and a de-icer spray could help too. Never scrape ice from your car with a credit card or any other makeshift scraper, as you could risk scratching the glass or damaging the paintwork. Don’t forget to clear the wing mirrors of ice as well.

6. Make sure all windows are de-fogged or de-misted before you drive off

Visibility is a huge part of road safety in winter. So before you set off, it’s essential that your front and rear windscreens and front windows are clear and fog-free. Don’t use your hand to wipe the glass, as you’ll only create smears and smudges.  

It should help to use the air conditioning at the same time as the heater. Push the A/C button while the heater is turned up to a warm temperature. This will release warm, dry air onto the windows to reduce the amount of water vapour inside the car and prevent new ‘fog’ forming. 

Turn air recirculation off. It may sound counterintuitive to suck cold air into the car, but replacing the moist, saturated air with new, fresh air will help speed up the process.

Some people swear by putting cat litter in a sock or small cloth bag, tying it up and leaving it in the car to absorb excess moisture. The non-clumping silica type of kitty litter may work best.  

What should I not do when trying to defrost my car?

Avoid using water to defrost your car. Most drivers know to never pour boiling water from a kettle onto an icy windscreen. The sudden change in temperature could cause the windscreen to crack.

But did you know that, because glass easily expands and contracts when there’s a change in temperature, you’re better off not using water at all? Water can cool down very quickly in cold air causing your windscreen to flex and crack. There’s even more risk of this if you’ve had a windscreen repair already. 

Don’t just clear a small gap of your windscreen to peer out of

You need good all-round visibility, so clear the snow and ice from all your car windows. 

Don’t concentrate on the windows only

Rule 229 of The Highway Code requires you to remove all snow that might fall off your car into the path of other road users. 

Don’t go inside and leave your engine running with the keys in the car

Your car could be easily stolen, and you might get a fine for leaving the engine running unnecessarily on a vehicle parked on a public road. 

Planning ahead for winter mornings

Give yourself a few more warm minutes indoors with these preparations to cut down your defrosting time.

1. Prevent ice on the windscreen

Use a blanket or a windscreen cover to stop ice forming on your windscreen overnight. Put the cover in place after you get home from work, while the car’s still warm. In the morning, just lift the cover off and remove any ice that’s formed underneath.

2. Fight the fog with shaving foam

According to the RAC, shaving foam is a secret weapon against window fog. Apply a layer of foam to the inside of your windscreen and windows, using a soft sponge or rag. Then buff it away with a clean cloth. 

If you do this regularly, you could have a mist-proof barrier as well as a sparkling windscreen.  

3. Park facing the sunrise  

The sun rises in the east, so pointing your windscreen in the direction of the morning sun may give it a bit of extra warmth, which could help reduce the likelihood of a large ice build-up. 

4. Stop your car locks from freezing

Frozen car locks are a nightmare for drivers with cars that still require a key to unlock the doors. A good trick is to place a magnet that’s the right size over the lock at night to stop the cold from penetrating – a fridge magnet could work. Simply remove the magnet afterwards and pop it inside the car for next time. 
 
A squirt of WD-40 could help prevent ice-forming and free the door locks up. Don’t forget about your boot lock if you need to access that too. 
 
A de-icer spray might also help, but before you spray, check the packaging to make sure you can use it on locks as some de-icers can harm metals. 
 
Whatever you do, don’t force the lock or you could end up with a broken key and an expensive bill to remove it.  
 
If you try these methods and still can’t get into your car, you might be able to get help from your breakdown insurance

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