Can I pour cold water on my frozen windshield

Social media users have been sharing posts that advise drivers to pour hot water on the windshield of their car to defrost it faster. This claim is false.

Reuters Fact Check. REUTERS

Examples can be seen here and here .

One post here reads: “Pour hot water on your windshield & it’ll defrost faster thank me later.”

The United States was hit with a winter storm this week that left usually warmer states unprepared against the cold. The weather has shuttered COVID-19 inoculation centers and hindered vaccine supplies (here).

The American Automobile Association (AAA) and the Automobile Association (AA) both recommend against using hot water on a windshield, which can crack or shatter glass due to the sudden change in temperature ( here , here ).

Instead, the AAA recommends starting the engine, setting the heater to “defrost”, adjusting the airflow to recirculate and moving the temperature control to full heat. As the ice melts, drivers can use a plastic scraper, the windshield wipers, rubber squeegee or a soft brush to remove the ice off the glass (here).

Glass companies around the country also advise against using hot or warm water on windshields in cold temperatures ( here , here and here ).

VERDICT

False. Pouring hot water over a car’s windshield during low temperatures can damage it, causing it to crack or shatter from the sudden temperature change.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work  here  .         

Rather than scrape and get cold hands and bits of ice everywhere, I use lukewarm water and just pour it over the windscreen and windows: this clears it very quickly of course.

So I wondered: is there any actual "harm" to the glass in doing this (I've been doing this for quite a few years without a single incident), but is it possible that the jump from ice cold to lukewarm could stress the glass?? It's obviously all safety and toughened glass, but anyway...

Cold water, straight from the tap will do it and be less likely to crack things.

Ive always done with no problems from cars ranging form a 1960s Merc 190SL to a brand new Fiesta. Maybe ive been lucky?

Fine as long as its not boiling hot

Thanks - I've also (doh!) just checked on t'internet as well and yes, tepid water or tap water should be fine... just not boiling water [which I've done in the past

Phew - I'm glad I'm alright with the pouring water trick: I'd hate to have to get and scrape

Once saw a windscreen literally pop out of the frame when hot water was applied, it was an old Hillman though. The guy got the shock of his life.

heated windscreens are great

Get hold of some methanol and whack that in your washer bottle. Instant defrost.

When I was at uni we were talking about nicking methanol for our cars and someone used acetone instead. Cue opaque windscreen.

Water out of the cold tap, not hot

I normally pour the water on the roof just above the screen to allow the temperature to adjust before coming into contact with the glass. Always works and haven't cracked a screen yet.

Having said that, clear the garage out. You know it's full of rubbish and the joy of driving frost free in the morning is worth it

Only someone with absolutely no grasp of thermodynamics would pour boiling water onto a frozen windscreen, surely?

Tepid water is fine though - I regularly use that, although on really cold mornings there is the danger of it instantly re-freezing, in which case scraping is preferable.

JonRB said:

Woman across the road from me did this years ago.

She comes out of the house with a steaming pan, this is going to end in tears I think.

Sure enough, shattered windscreen...

I just use a can of de-icer. 5 seconds of spray on the windscreen and then use the wipers.

Plotloss said:

It was just a small stonechip as well, which clearly altered the thermodynamics of the windscreen (thanks Jon).

Bloke from RAC Windscreens almost died laughing when I told him what had happened.

I have it on good authority that urinating on your screen is highly effective

Always use tap water and it works fine. Looking at the Horizon programme this shouldn't be such a problem in the future

If you have a small dink in the metal work. Wait for a really hard frost and then pour boiling water onto the affected metalwork. Helps if it is horizontal at the time but worked for me on a bonnet dink i had on my Golf.

Re frozen windscreens get in car, start it and switch on heated front screen, seat heaters etc etc lovely

What is the fastest way to melt ice on a windshield?

Is it safe to pour water on a frozen windshield?

Can you use cold water to defrost windscreen?

Can cold water break a windshield?