Well here at least it is good to have windows open as long as the sun is shielded. Living room with double doors to both front terrasse and rear veranda all open wide but as it is east/west facing very little sun gets in except in the evenings when I have shutters half closed.
The south facing kitchen would get very hot but with veranda windows open and a curtain between it and the kitchen it is relatively cool, especially with all interior doors open.
As I said before, very rarely use the a/c.
My nephew has a Grade 2 listed cottage in Cornwall. The listing is on account of its curved front window with small panes of glass. It was originally from a ship.
The secret in my stone house is to keep the windows and Velux tightly closed when itâs summer. It stays beautifully cool. If you open the windows and let the warmth in it will stay warm.
Old stone built houses can be snug but need to be properly insulated. Digging out the ground floor to add layers of rubble base, pozzolane, and lime mortar really transforms the place, then put the tiles back over the top. Chaux-chanvre / hempcrete to 10cm on the walls also helps insulate, and the lime will help to regulate moisture in the air as well preventing condensation.
We have all windows open at night, once the temp has dropped sufficiently. Mozzie netting keeps out all the buzzers and the whole house refreshes itself, in preparation for the next day. 
I disagree with insulating the stone walls. The house remains warmer in the winter when the stone is exposed as it retains the heat. When I come downstairs in the morning the rooms are always warm. By insulating the walls you heat only the air which then cools down very quickly once the heat source is removed.
I think the important word there is âinâ, in our case we let the air âmove throughâ the house with all doors and windows open but with sun excluded. But other constructions may be different.
Thats why every house down here has the shutters closed during the day but the windows are open inside - its the sun shining in that makes it so hot. I revert to vampire existance from June onwards or even before, coming out to play when the sun goes down.
But I said just that. You chose to quote me out of context after I started my post with, â The secret in my stone houseâŚâ. From what I can gather our houses could not be much more different so what works for you might well not work for me. If I let warm air in during the summer the house warms up and stays warm. The way to keep it cool is to keep the windows shut.
I did not misquote you, I ended with my understanding of your point, thus,
If my doors and windows are open the heat will pass through the house warming it up. I donât see that there is any difference to me letting the heat in and you letting it pass through. The point is if I let warmth in it stays in. If I want the house to stay cool I keep the warm air out. Luckily I donât suffer from the same heat levels as Shiba and she probably has much bigger windows than me so I donât need to keep the shutters closed, in mid summer the windows are not in direct sunlight.
Ah⌠for me, with windows (on all levels) facing all 4 points of the compass, I do also close shutters when the sun is actually hitting windows⌠thus the northern aspect rarely has itâs shutters closed, even if I need to keep those windows closed because the âair tempâ is toooo high (40câs). quite often the northern aspect helps the house to gulp some cooler air during the day⌠just depends on the direction of any wind⌠so I leave those windows open for a while.
Itâs a bit of a game and needs me to be on the alert⌠but thatâs no problem.
I live in Normandy, when and if the sun comes out and its warm, everything (with fly screens) is opened up.
Yes,my living area has a 3m wide sliding patio window that the sun comes through from before midday to sundown. I had a solid granite house with metre thick walls previously but we insulated it with plasterboard on railing with insulation behind as I did not want the stonework showing plus it also hid the electric cables and water pipes which look so ugly if just left showing and it got very warm in winter from the woodburner. Stonework does keep in the heat but a lot of it takes hard work to get it to stop shedding muck from the construction and Iâve seen folks actually paint stonework in Brittany with varnish to stop this, which is not a good move - the traditional build there was to use cow dung in the walls to fill the gaps in the stonework so not very pretty.
Thereâs a perishing wind from the north⌠brrrrr⌠windows and shutters closed.
But the south-facing âfrench windowsâ have been open for a couple of hours, while the sun came out to play⌠phewâŚ
My house only has south facing windows. 
What colour are the shutters, dark ones in a warm climate will be getting hot, whereas white mediterean style reflect some of the heat? Being in the Centre we can have what we want in our case a brown sort of colour.
gosh, never been in that situation wherever weâve lived⌠always had windows on a few (if not all) sides⌠now Iâm wondering if your house is actually a troglodyte dwelling 
Breton longères are like that, windows only on one long side, usually west or south facing because of the winds. Mine only had windows facing the sunset and to put more in was too difficult without a lot of stone removal and hard work on metre thick walls.
