Teacher hacks: how to defrost your car quickly

On winter mornings, driving to school can be needlessly complicated by poor attempts at car defrosting, says Gemma Corby

Gemma Corby

Teacher tips: How to defrost your car windscreen in the morning

You’re running late for work, having snatched a few extra moments of shut-eye, but you reckon you’ve made up for lost time by forgoing mascara and breakfast.

But wait, what’s this fresh obstacle between you and your pre-briefing cuppa?

A frozen solid car. Great.

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Don’t worry, Cinderella will go to the ball (or to her Year 9 registration). Here are five tips to get you mobile:

Defrosting your car


Hot air is your friend

Unlike Jennifer Aniston in the ‘90s, I am going to start with the science bit. Warm air holds more moisture than cold air.

So, when temperatures plummet overnight, the moisture that was being held is released, resulting in tiny water droplets fogging up your windscreen.

Your first step should be to get in the car, start the engine and crank the heat up. (Note: do not leave your keys in the ignition unattended – apparently car thefts increase on frosty mornings).

Cold air is also your friend

This sounds contradictory, but let me explain; cold air is dry, so it has a greater capacity to absorb water as it warms.

Open your windows (as long as it isn’t freezing cold or raining outside) and switch the heating on. Make sure you turn off the inside air recirculation; you want to replace the humid air inside your car with cold, dry air from outside.

Zapping ice

If you have some de-icer in your car, it’s a gold star to you. This is probably the easiest way to banish the ice.

But what if you are caught short? It might be tempting to reach for the kettle, but hot water can cause glass to crack. Also, if it is a particularly cold day, then it could refreeze. Instead, try using two parts surgical spirit, to one-part water.

 If you are using a scraper, make sure you are gentle, so as not to scratch the glass. If you find your car to be a scraper-free zone, then use a credit card (or something less valuable like a store points card). Use the long edge, as it is less likely to bend.

Prevention is better than cure

Back in medieval times, people would prevent their cars from frosting over by rubbing a raw onion over their windscreen the night before (OK, perhaps only part of that statement is accurate). But, perhaps surprisingly, it is said to be an effective method. Cut an onion lengthwise and apply the night before. The oils in the onion are said to prevent frost from forming.

Other approaches include spraying your windscreen the night before with a solution that is three parts vinegar to one part water, or using a windscreen cover. If you do not have a proper cover you could use any carpet remnants, or an old tablecloth or shower curtain.

Avoid using newspaper as this is too thin and will freeze to your windscreen, meaning you may have to drive to work with Boris Johnson’s frozen face staring at you.

You can fill a sock with cat litter (or use dehumidifying crystals) and place it on the dashboard, near the windscreen, to absorb any excess moisture. 

Finally, do not forget your wipers. Do not leave them in auto as they will be straining to move and stick to your windscreen, which could damage the mechanism. Gently pull them loose from the icy grip of your car’s windscreen.

Gemma Corby is a freelance writer and former special educational needs and disability coordinator

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Gemma Corby

Gemma Corby is a freelance writer and former special educational needs and disability coordinator

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