[sdeframond]

Insulation is actually helpul against heat too!

But since modern buildings usually have huge windows, we're letting in about 1kw of heat from sunlight per square meter of window. That's 6kw for a 3x2m bay window, or about the equivalent of 6 electric heaters at full power.

Block that heat ouside of your house with all kind of shade you can get: trees, blinds, adjustable shades, rolling shutters...

Also, close every openings during the day, vent at night.

[OptionOfT]

> Insulation is actually helpul against heat too!

Yes, until you reach that tipping point where once warmed up, you can't cool down anymore.

[scarecrowbob]

I don't know your situation but surely you've tried ventilating at night and then closing up the house at a specific time in the day?

I only ask because when I moved from the US south to the high desert in NM (about 2KM) I had to learn how to time that transition.

Very few folks here run A/Cs, we generally have homes designed to stay warm and during the summer usually fans go on about bed time and off in the morning, and that's enough to keep things cool because of insulation.

It was not obvious to me how that worked and I spent one very sweaty summer before I got the timing correct.

Of course, if the nights are hot (which sometimes happens) then that doesn't work so well.

[whatevaa]

Ventilating at night doesn't work at all when nights are hot. And now it happens oftenly, not sometimes. That is a bigger problem than hot days.

Also, all the activity you do inside your insulated home also increases temperature. Human body itself is a small space heater. At some point, you gotta get that energy out somehow, and if nights are hot, there is no way to do that except via a heat pump.

[sdeframond]

It may not be enough but it does work.

When it is 40C max by day and 22C min by night, for example, the outside is still cooler than the inside at night. So ventilating will have a real impact.

With this you might reach 25-26C inside in the morning and 29C by the end of the afternoon. It is hot but generally OK with fans, depending on humidity.

Then you can turn the AC on during daytime on top of that, which makes more sense than relying only on it.

[scarecrowbob]

I mean, fortunately for me it's dry enough that I can run a small swamp cooler for the couple of weeks a year where those are the temps in my place. But yeah, you're correct that this is what it looks like where I am at, temperature-wise.

Though I have no A/C, per se... I have thought about it. I'm 100% off grid, but the only time I would like that is when the sun is so far up that the batteries have all already charged.

[gib444]

(UK here)

This is all the usual advice, which works for a few days, but during a period of over a week of high temperatures, there's nothing you can do.

The sun will eventually heat up every part of the house and turn it into a radiator.

Even when night time temperatures drop to 17c, I have my have windows open at 10pm with a decent cross-wind, my bedroom temperature may drop from 26c to 24c after 2-3 hours, but if I close the windows, it jumps to 25c in ~30 minutes...

The streets probably don't help either - no trees, just asphalt, front yards with paving slabs etc

[sdeframond]

> Even when night time temperatures drop to 17c

That's pretty nice actually!

I am in a brand new rooftop apartment, so pretty exposed to heat. I can keep 28-29C indoors when it's 38C outdoors. That's hot but workable with a ceiling fan.

At night we open all windows and have a ceiling fan above the bed. We've got about 24C indoor in the morning, with nightime outdoor temperature at about 21C.

Obviously I keep physical activity to early morning and late night.

[gib444]

17c outside just to be clear, highlighting that that it doesn't serve much purpose in cooling inside the house

We also have high humidity which makes 25c to 30c at night very uncomfortable for us Brits.

People often forget about humidity when telling people they don't need AC

And you have to remember we're a country of people used to max summer heat mostly being around 20-22c and many people will sleep with the window partly open in the depths of winter

[sdeframond]

> People often forget about humidity when telling people they don't need AC

True that it is not so humid here in the French alps.

But to be clear: do get an AC if you need to. Please dont rely only on your AC though. Turning on the AC (eg just pressing a button, really) is so easy we tend to forget about the rest... and end up burning even more fuel.

[arethuza]

Scotland here - have heard people from London talking about moving here for the weather.. which isn't something I ever expected to hear!

Was 10C this morning when I went out to walk my dog, in a t-shirt and shorts!

[ndsipa_pomu]

I'm surprised you need to put clothes on your dog

[gib444]

> Was 10C this morning when I went out to walk my dog

I hope you didn't get heatstroke ! XD

[yossarian88]

That's a bit high. 1kw is pretty much the peak per M2 when the sun is directly overhead and normal to the surface. Coming through a window obliquely it will both be less at the source and trig reduces it too, along with what's rejected by the window too. But I agree with the general point!