Which is cooler windows open or closed.

If it's hotter outside keep them closed. If cooler outside open them.

Yup. As a PP pointed out, it's not rocket science!

It’s amazing that there are people on the thread arguing about this when all that is required to figure it out is the most basic knowledge of physics which everyone is taught at school. It’s blindingly obvious.

Noo, it doesn’t make any difference to the air temperature. A through draft of air warmer than the air already inside your house will obviously increase the temperature in your house. This is why fans exist; so tgat you can have the movement of thw internal air without bringing hot air into your house by opening windows during the daytime when it’s hotter outside than inside!

at 6 a.m. you can open all the windows and hope a breeze springs up. Only close them once the air temperature outside rises to the indoor temperature, then close and pull curtains, etc. As soon as the sun goes down, get ready to open windows again. It's relentless at the mo.

I follow the sun

When I get in from. work in the mornings, the sun is reaching the front of the house, so I draw the blinds, pull the curtains that side of the house, and open the windows the other side

Late afternoon when the sun is in the rear, I close those windows, pull the curtains and open the front

I keep all internal doors open as well to let air flow

We haven't had the temps you guys down south have had, but high 20's when we are used to mid teens, its been hot for us as well

As someone who has lived in Australia, close the windows and shut the curtains as pretty much everyone is saying. Open them in the evening once it's cooler outside than inside your house, and we leave them open all night but our bedrooms are not on the ground floor. Has been bearable for sleeping in our house this week.

Curtains and windows closed during the day

Window open, fan going, lights off and curtains open at night

Unless you're on the ground floor, of course

The wind today was around 30c, so far higher than the internal temperature indoors! The breeze doesn't cool a thing when the temps are so high. It just dries you out more.

It doesn't though. See previous post. If it's a warm breeze it will heat up the room even if you feel cooler when the breeze hits you. Windows closed and fan on will actually keep you cooler.

Depends if there is a breeze too, we get a through draft going which really helps

electronic thermometers take the guess work out of this. Outside, back and front, and in a couple of rooms. As pps say, when it’s cooler outside than in open the windows. And vice versa. It’s not rocket science.

A breeze does not equal cool air. Even warmer air moving over your skin can feel cooling but all it’s doing is heating up the room, and you’ll feel it as soon as the air stops moving.

How can people find this so hard to understand?!

@LancashireButterPie what on earth are you going on about greenhouses for?! They are literally made of glass - unlike houses which have insulated roofs and walls!

If the air outside is cooler than the air inside, open the windows. If it's warmer outside, keep the windows closed. (Same principle as in winter when it's colder outside than in - you keep the heat in and the cold out.) If it feels stuffy with windows closed, use a fan.

It also helps massively to use blackout blinds and curtains. We keep the blinds and curtains closed on the sunny side of the house (and if we'll be out all day and unable to keep closing and opening, we just close everything before we go).

If the temperature cools down in the evening, overnight and in the early morning, you can easily keep your house at a reasonable temperature by following these common sense methods. The problem is when the outside temperature doesn't cool down enough overnight and you can't cool the house before the next boiling hot day.

What extra tasks require someone at home?

You open it all up early before work (I was up at 5am yesterday to do this and walk the dog) then close it up before you leave the house.

Open it all in the evening when it cools down then close what you need to for security at bedtime.

Rinse and repeat.

if the sun is beaming then all closed, if the sun disappears then try opening

It's great all the posters are around to open and close windows when necessary.
I'm in a flat and work full time.
When I leave the sun is fully on one side and by the time I get back it's on the other, It's not got below 30 for a few days even overnight!

Open all the windows when it's cool (early morning and late evening) and then shut them once the outside starts to heat up. It's definitely cooler inside my house than outside, because from about 9am we've shut the hot air out by shutting the windows. At 6am you were definitely right, by 10am he was...

If outside is cooler than inside and you have a nice cooling breeze then windows open. When it’s close to outside becomes warmer than inside, windows closed.

I dont think it makes much difference, my curtains are closed and window open but there's a nice breeze so its helping me cool down

depends on the house but I would say open for mine as when I go outside it’s cooler than in my house

It certainly doesn't make the difference I hoped it would. I'm wearing myself out trying to keep this red brick hellhole cool....Foil on the windows, shutting windows, blinds and curtains as soon as it starts getting warm outside after leaving everything open overnight.

It's still absolutely bloody baking upstairs by 3pm no matter what I do.

The house needs painting white that's for sure.

All of our windows are open with the blinds closed. Fans put in strategic places to move the air. It’s lovely and cool in my house.

I feel the cold. Not that 25° indoors is cold but i was comfortable under the duvet, certainly not hot.
dh can’t sleep under the duvet when it gets above about 20, he runs very hot.

We open windows on shaded side then when sun moves around we shut them and open the other side up. Keep curtains closed and reopen once cooler at night

Same. Seems bizarre to need a duvet at 25 degrees though.