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De-icing a car windscreen using hot water in a bag method

93 replies

Hosoan · 03/01/2026 13:44

Has anyone used this method to de-ice a car windscreen, where you use a plastic bag of hot or warm water and move it over the windscreen to melt the ice?
If so has anyone experienced cracking of the windscreen? I know it's a risk but am not sure how much of a risk.
I am aware not to just pour water over as it can freeze on the ground making it slippery, but using a bag avoids that.
Any experiences please

OP posts:
BeardedBarley · 03/01/2026 16:33

I’ve been driving for 30 plus years. I’ve been pouring very hot water on windscreens every winter with no ill effects.

megacat · 03/01/2026 16:35

Politicians247UnderwearExtinguishingService · 03/01/2026 16:27

Whichever method you use - water in a bag or pouring from a bottle - the key is lukewarm. Never use actually hot water.

The windscreen freezes at 0°, so if you used water that's even only 15 or 20°, that should be plenty warm enough to unfreeze it. I'd go a bit warmer personally, but nothing too major.

Windscreens are made as standard worldwide, so if you lived in a very hot country, the summer rain could fall at quite a high temperature - and nobody would ever expect that to crack a windscreen.

It’s not just the hot water, it’s pouring it on frozen glass that causes the crack. A hot country wouldn’t have that problem.

Ineffable23 · 03/01/2026 16:37

babychaos · 03/01/2026 16:31

Please don’t leave your engine running while
you de-ice. An idling car can produce twice the amount of harmful omissions as a driving car. It’s also now a fine-able offence - the law changed around this relatively recently.

https://www.rac.co.uk/drive/advice/winter-driving/dont-get-fined-for-de-icing-your-car/

I don't have a driveway. Obviously I never leave my car unattended but I can't drive off until the car demists and the car won't demist until it has warmed up, so I don't know what I would be meant to do?

I just deice with a scraper.

The hot water thing really annoys me if it's not in a bag, because I have commuted on foot before and it used to be so slippery where people had done that.

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snoopymug · 03/01/2026 16:42

cinquanta · 03/01/2026 15:53

I put a fan heater on the centre armrest in my car the night before and turn it on 20 minutes before I need to leave in the morning. Clear windows inside and out, plus a warm car.

How is it powered?

somanychristmaslights · 03/01/2026 16:43

Yep, warm water from the tap in a ziplock bag. Works a treat!

vanillalattes · 03/01/2026 16:45

babychaos · 03/01/2026 16:31

Please don’t leave your engine running while
you de-ice. An idling car can produce twice the amount of harmful omissions as a driving car. It’s also now a fine-able offence - the law changed around this relatively recently.

https://www.rac.co.uk/drive/advice/winter-driving/dont-get-fined-for-de-icing-your-car/

I don't have a choice. I have an old car that fogs up inside as well as outside - the only way to clear the windscreen and make it safe to drive is to run the engine for a few minutes.

MzHz · 03/01/2026 16:46

ramonaquimby · 03/01/2026 13:47

Why can't you just use an ice scraper?

Edited

Only fools use a scraper

large bottle of water - 2L or 3l milk carton filled with warm - NOT HOT - water

pour on glass, defrosted car in one splash

and no frostbite

user1496146479 · 03/01/2026 16:50

I just place a towel on the windscreen of overnight & whip it off in the morning. Works perfectly. Fancier versions exist

YouLoseYouSnooze · 03/01/2026 16:55

cinquanta · 03/01/2026 15:53

I put a fan heater on the centre armrest in my car the night before and turn it on 20 minutes before I need to leave in the morning. Clear windows inside and out, plus a warm car.

I assume it is plugged into the cigarette lighter?
If you could get one of these operated by remote control so you could start from within the house, that would be amazing.

Muchtoomuchtodo · 03/01/2026 17:00

I’m a scraper! I like my windscreen to be dry, especially if it’s still freezing temperatures when I’m clearing it otherwise the melted ice (water) can refreeze - even the thin layer left by the wipers which is just a pita!

IfIwasabluebird · 03/01/2026 17:02

Pouring water just leaves a potentially icy puddle though. Some of my stupid neigbours do this on the car park.

vanillalattes · 03/01/2026 17:05

IfIwasabluebird · 03/01/2026 17:02

Pouring water just leaves a potentially icy puddle though. Some of my stupid neigbours do this on the car park.

I'm glad someone else said this - all the people pouring water, what happens the next day when it's frozen all over the roads?

QuietLifeNoDrama · 03/01/2026 17:06

I’d use one of those silver foil type windscreen covers. Just lift it off and drive away in seconds. No cold hands or faffing

queenofwandss · 03/01/2026 17:08

Hot water bottle? Bonus you can then use it in the car while it warms up.

Muchtoomuchtodo · 03/01/2026 17:47

QuietLifeNoDrama · 03/01/2026 17:06

I’d use one of those silver foil type windscreen covers. Just lift it off and drive away in seconds. No cold hands or faffing

What about the rest of your windows? Or do you only look forwards when driving?!

AyeKarumba · 03/01/2026 17:51

OakElmAsh · 03/01/2026 13:51

Big jug of hot water from the tap (so not boiling) has done the job perfectly for me for the last 25 years, and nary a cracked windscreen in sight. Couldn't be faffing around trying to get it into a bag and roasting my hands in the process 😂

It’s really not hard to put water in to a bag.

Notmyreality · 03/01/2026 17:54

Get a car with a heated windscreen. Game
changer.

MaloryJones · 03/01/2026 17:54

ramonaquimby · 03/01/2026 13:47

Why can't you just use an ice scraper?

Edited

Always one
She doesn't want too , obviously

Notmyreality · 03/01/2026 17:59

19lottie82 · 03/01/2026 16:19

  1. you might not have any. 🙄
  2. some people don’t like using the chemicals. 🙄
HTH
  1. Plan ahead for winter. I always have de-icer in my car and also at home. 🙄
  2. If you are that worried make or buy a natural one or make your own at home. There are multiple recipes online to put in a spray bottle. 🙄

HTH

SalmonOnFinnCrisp · 03/01/2026 18:01

BalladOfBarryAndFreda · 03/01/2026 13:48

I just use spray de-icer (trigger spray type, not the aerosol deodorant can type). Hot water poured on is fine but just don't use kettle hot / boiling or anything close to it, it needs to be warm or you run the risk of cracking.

This

I wouldnt risk hot water. at all.

Deicer and scraper in this house all the way

Allthegoodusernamesareused · 03/01/2026 18:03

I had a horrible accident a couple of winters ago slipping over on the ice caused by someone de-icing their windscreen by pouring water over it, it had run off their drive onto the pavement and frozen over. Broke my coxyx. I wish people were more aware of the consequences! Warm water in a bag seems like a much safer solution (or de-icer and a scraper).

joeninetey · 03/01/2026 18:07

QuietLifeNoDrama · 03/01/2026 17:06

I’d use one of those silver foil type windscreen covers. Just lift it off and drive away in seconds. No cold hands or faffing

Don't they get stolen ?

Isobel201 · 03/01/2026 18:13

joeninetey · 03/01/2026 18:07

Don't they get stolen ?

A cover that you can fold inside the door and lock it then it won't get stolen. I've lived on a public road for years and always had my engine on for a few minutes whilst de icing and de misting the window. Never had a policeman walking down the road at 6am in the morning and never got fined. I park on a driveway now and fortunately don't need to set off early in the mornings so I rarely have to clear my windscreen now.

EleanorReally · 03/01/2026 18:14

I have had success. Not hot water but warm in a bag and it also deices the inside

Ponderingwindow · 03/01/2026 18:26

This is crazy. Bags of water?!?

I live in a land of snow and ice for winter. Just turn on the car and use the defrost setting. Let the windows warm up for a minute. Remove snow from horizontal surface. Start scraping with the more vertical windows that likely aren’t as bad. Do the angled windshield last once the car has done the work of getting it softened.

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