AIBU to keep the windows open?

[Lochroy]

It seems to be the new 'thing' that we should keep the windows on the sunny side of the house shut to prevent the external warmer air from entering the house.

I understand the logic.

However, with the windows shut, and even with blinds down, the glass act as like a green house and the inside ends up hotter than outside. So surely that's worse???

Plus there's a smidge of a breeze.

I'm not actually that bothered by the heat, I'm just trying to get my head around the argument.

You are meant to shut the curtains as well to avoid the green house impact you mention. The idea is the air is hotter outside than inside so you want to keep that air out.

I keep them all closed on the sunny side, pull blinds down and open everything on the shaded side and then swap over as the days goes on.

Your windows, your choice, knock yourself out

The science of temperature differences between inside and outside the house isn't a new thing, I'm sure I've read explanations on the eleventy billion other threads about this 😁

I don't think it makes much difference. I am sitting in the house with the front window and the back patio doors open and there is a lovely breeze blowing through from the front to the back.
I do shut the bedroom curtains all day though as the sun shining through that window makes it like a greenhouse in there at night.

Use of blinds/shutters/windows/curtains makes a significant difference.

If you choose to leave windows/doors open and get a breeze through your house you may feel good ATM but that’s because the air movement produces some degree of wind chill…

However you will be introducing outside air at external ambient temperature into the house. Ultimately your house will heat up more rapidly towards ambient temp more rapidly than somebody who has kept the windows closed and blinds/curtains/shutter closed.

So... if the air is hotter outside, closing the windows will keep it out

But the temperature of your body and the temperature on a thermometer are not the same thing, bodies cool by sweating so if opening the windows creates a breeze or reduces humidity indoors you may well feel cooler with them open

I covered mine with tin foil on the outside (esp those with no blinds) and this has helped enormously and also means I can have them a bit open for a breeze without incurring much solar gain. I recommend it. Spray the glass with water and the foil sticks by itself.

It’s 28 in my house right now, so the temptation to open the windows is strong. But it’s 34 outside so opening them is only going to make it worse! Do you have a room thermometer so you can figure out if it’s actually hotter inside or just feels hotter due to lack of breeze? If it’s the latter you’re better off keeping the windows closed and using a fan.

It definitely works for me - I’ve got all my windows and curtains shut and I’m sitting here in t shirt and shorts feeling slightly chilly if anything. Outside it’s 33 degrees. I’m hoping to keep the house as cool as possible for as long as possible over the next day and a half.

I always keep windows open, and curtains closed till the sun goes round to the other side of the house. Always worked well for me.

I think having windows open on a shady side of house brings in cool air. Curtains/blinds closed to block all sunlight of course. Only a crack open for windows on sunny side to create a cross breeze. Managing to keep house 10C cooler than outside this way. It’s 35C outside and 25C inside.

In my house its hot with the windows open and hot with them shut. Personally I prefer windows and doors open with curtains shut.

No denying that a breeze can feel beneficial but there’s no magic ever lasting pool of cool air outside buildings….if the ambient air temperature is 35 Celsius, which it may well be soon in some parts of the UK, then that is or very soon will be the temperature of the air that is flowing in through windows….

Ultimately it’s a trade off between having a breeze now and maybe a house that hotter then it needs be overnight.

Here's my thread from yesterday

www.mumsnet.com/talk/_chat/4591794-does-keeping-the-actual-windows-shut-help?page=3&reply=118605174

I am experimenting today and all windows and blinds are closes

currently 34c outside, 27.6c inside

closed*

The thermometer in a shady bit of my south facing garden is registering 42 degrees. I popped out to hang up the mattress topper I'd washed, before lunch, and the heat was painful. With the doors, windows and curtains shut, the kitchen is a much more bearable 27 and I'd like it to stay that way.

This is the first time I've tried the windows and blinds closed thing due to having a curious cat with apparently mild suicidal tendencies when seeing an open upstairs window 🤦‍♀️

So far I actually can notice a big improvement, definitely seems to be keeping the house cooler.

I woke before 6 this morning when it was a lovely 17 degrees. I opened all the windows in the house for a couple of hours then shut them once it felt like the temperature outside was getting to be the same as inside. That also seems to have helped so far

No it won’t because the air flowing through my house is coming from the shady side which is not 35C.

My house gets a breeze + is cooler overall. The proof is in all the people on this thread with windows closed are reporting 34C outside and 27.5C inside…compared to my 35C outside and 25C inside. Obviously, their closing all the windows is making their home a few degrees warmer not cooler.

Just gone outside and measured shady side of house outside it is 27C and sunny side outside is 42C. Shade makes a huge difference in air temperature- it’s not “magic” but a function of blocking sunlight. Indoors still 25C.

Still a good 2C+ cooler than those with windows closed and similar temps outside.

Definitely closed for us. I closed all the south facing windows, blinds and curtains at 9 this morning and put fans on. I left all north facing windows open and at 11.30 my kitchen - dining area was 27 degrees so I’ve closed all of them now and my kitchen - dining area is now 25.5 degrees. The only windows open now are the loft extensions windows to let the heat out and that how we are going to stay until it gets cooler outside than in.

FWIW we’re non Uk, somewhere hot in summer (certainly is ATM) and local practice and custom is windows and shutters open overnight once outside temp is below the temperature in the house, and fingers crossed that happens…

In the AM , everything gets closed up before it gets hotter outside than in.…

Regardless of building insulation quality you can usually maintain a decent differential (maybe 10 -15 degrees cooler inside) for a day or two.

If the heatwave lasts for multiple days or even weeks you start to lose the differential as the building gradually absorbs daytime heat.

It's not a 'new thing' OP, it's what warmer countries have always done. It's just that the UK is warming, so needs to do what other countries do.

I keep my south facing ( this very hot) back patio door open but with all the blinds on that side of the house down. I also open my front door which is on the north shady side of the house. This creates a through breeze

I also have fans on. The front ( north facing) rooms in my house are fine and not at all too hot.

I don't have an internal thermometer but I went out in the garden to hang up washing just now and the south facing room is definitely cooler inside than out though hotter than the front room. I felt the difference as I moved the blind aside to come back through the open door

The house will get hotter as the afternoon goes on though . Eventually the front room will feel hot too

Have had all mine closed and covered since about 8.30 this morning. So far, so good. House is not too bad. Outside is absolutely baking, although not sure of actual temp.

If you have a window open, if the temp outside is warmer than inside your house, you will be moving your house warmer, it’s scientific fact!

I have all windows and curtains closed from around 9ish. My sitting room is 22 at the moment and 32 outside.