Kitchen foil on windows in full sun

[WindyMillerDrinksCider]

I've put kitchen foil on the inside of double glazed windows at the front of the house to keep the heat out. It's really effective because they get full sun. However, Google says it can crack the glass because of the heat so it should be put on the outside.
Does anyone have experience of this either way - cracking or no cracking?

I have used it on a west facing bathroom window for the last couple of years but this year bought some uv blocking mirrored cling from Amazon because I was a bit tired of the crack house vibe.

I put white sheets on the outside of my back door and windows - I also put the garden table parasol on tilt outside the very south facing window as a first line barrier - it does a brilliant job. The back window doesn’t heat up half has much as it has done over previous years.

Yes, I do similar with a white sheet.

My daughter has black out blinds up in her window, I hardly ever bother to take it down off one of the windows and it's been there 5 years with no issues.

I did it today and it worked fine -- and my room is cold.

Definatly do this

It would depress me how ugly this looked in my beautiful home so I think I’d just spank a shed load on the best fan I can afford!

Our neighbour has two of those silver things for keeping windscreens cool on the outside of his patio doors. Looks a bugger but at least he can breathe. He works all day and it gets full sun it must be awful when he forgets.

https://www.heatwavetoolkit.com

That’s the best website for advice. Solar shading on the outside of windows.

you can put it on the outside. When you have it inside it traps the heat inbetween the glass pane and foil. On the outside it reflects before the window pain.
I had it on the inside last year and it left marks so this year we have done the outside of the windows and it’s made quite a difference!

How did a bedsheet stain your window?

Ah yes, anyone writing notes like this should definitely be in charge of caring for newborn babies. Of course she didn't do it! Innocent until proven guilty!! Oh wait...

Wrong thread, yiiiiikes

I've never heard if this method before!...

Cardboard? We have Honeycomb/Cellular Shades in the bedrooms and they're great at insulating, keep summers heat out and winters cold out. They're made of cardboard.

Any thing on the outside that shades will work a lot better at keeping you cool than things inside.
I use old duvet cover on the patio door and some old towels on the windows on the back of my house that faces south east. The duvet I put over the top of the door and just close the door as far as it will go, then tie the handles together. Similarly all my windows fully open, so use the tilt to allow me to put a towel over and push it as closed as it will go.
I tried wetting the towels once, that seemed to work a bit, but they dried out so fast!

I tried this on the inside and feeling the tin foil it got pretty hot.
Much much more effective on the outside of the windows.

We had something black and polystyrene in our south facing window, it caused a crack, the window was mightily hot to touch. It was only October too! (Halloween decoration)

I do this and I have the window open a tiny crack to allow any heat build up out.

It is more effective to have the blanket up and window open a crack than not to have it.

Thermal stress causes glazing in double glazed units to crack. It's especially common where you have either a South or west facing window which heats up to a high level with something reflecting heat onto it on the inside, but also east facing where you get morning sun and it's cold on the outside pane due to the temperature differential. So basically, if you have a north facing window that doesn't really get much direct sunlight you are probably fine, otherwise out it in the outside...

*put!

Yes, mine are single pane old sash windows

I think if you find yourself smearing yoghurt on your windows to block out the heat… it’s time to move.

The back of our house is south facing. We are very cool in the front so don't do anything other than keep the internal shutters closed until the evening.

That said, I am expecting units to 'blow' as this has happened every time we have had a heatwave (twice since we have lived - 11 years).

I think you are meant to put shutters/silver cover on the outside to prevent the glass from getting hot. Putting it on the inside isn't as effective and doesn't stop the glass from heating up - and then blowing. If it happens again this year then I will be thinking about getting some external shutters or blinds fitted in the future, when I replace the units.

You can smear the outside of your sun facing window panes with calcium carbonate which does a great job of reflecting UV. When you remove it after the heat wave your windows will sparkle!

This is basically greenhouse shading wash, although the yogurt might be messier / go mouldy.