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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 2 days ago

> 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 2 days ago

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 1 day ago

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.

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.

gib444 2 days ago

(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

> 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 2 days ago

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

> 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 2 days ago

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 1 day ago

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

gib444 1 day ago

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

I hope you didn't get heatstroke ! XD

yossarian88 2 days ago

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!

tarsinge 2 days ago

One way insulation does not exist. If your house is insulated to keep the heat inside, it is also very good at keeping the heat outside / cold inside.

Also tangentially many Europeans seem to be confusing insulation with inertia, saying their house is correctly insulated against the heat when in fact it’s just a stone building that is taking more time to heat up. At the extreme you have European churches buildings that are very badly insulated but stay cold most of summer because of all the stone mass.

One thing Europeans have yet to realize is that good insulation only works when the nights are cold enough to evacuate the heat before it reaches the inside, and that during a strong heatwave there is no adaptation possible, AC is needed.

> many Europeans seem to be confusing insulation with inertia

That is true. I heard that many times...

> during a strong heatwave there is no adaptation possible, AC is needed.

At some point, yes, obviously. But in many cases I see people installing an AC without actually trying anything else. And then it is an energy orgy: AC set to 16C with sunlight hitting straight to the middle of the room...

cucumber3732842 2 days ago

>So we've been stupid "solar oven" buildings for 50 years while climate scientists were warning against extreme weather events and, now that said extreme event arrives, the best we find is to rush to aircon.

>Seems pretty short-sighted to me.

The same industries that got rich over those 50yr selling BS we didn't need because the government mandated it are gonna get rich over the next 50 installing smart ventilation and heat pump A/Cs and whatnot when the next pile of mandates to undo the ills of the prior ones gets written into the building code.

Seems pretty long sighted to me.

bamboozled 2 days ago

I feel every comment section related to weather and climate seems to have the same winging about buildings. Cold? Europe has amazing buildings, hot? Europe has been building ovens... it's interesting psychology.

Edit: We cannot blame people for buildings things that worked when we had a stable climate but are no long suitable for all these extremes. We needed to fix the emissions issue 30-50 year ago to avoid this. We knew it and we collectively ignored it. I get your point, we could've "planned ahead" but if you build something that wasn't suitable / cost effective for the time it was built, you'd be out of business.

50 years ago no one was going to pay extra for a building that might be important in 100 years because we didn't stop burning fossil fuels in time.

> you'd be out of business.

Correct. And we'd be "out of business" too as a country if we decided alone to fix emissions. Other economies would have passed ours because burning oil is so damn useful.

Thing is, I don't feel we are changing much in this respect. Now the best idea we come up with is burning more fuel for aircon...

queenkjuul 2 days ago

> Now the best idea we come up with is burning more fuel for aircon...

I mean really what else is there? We can't undo the warming, we can't rebuild every building in Europe (even if we could, would it work? Winter will still happen too). We can install solar panels and air conditioners, though.

We can install adjustable shades and ceiling fans. Cheap and efficient. It practically pays for itself in saved energy bills if we decide to add an aircon anyway. Plus the saved energy saves carbon emissions too.

We can update building regulations so that new building are better.

We can plant trees. It brings shade in summer but lets sun through in winter.

We can stop taking the plane.

I mean, there really are tons of things to do!

stavros 2 days ago

The one thing I want is for everyone to tick the box on their power company's website that says "only give me electricity from renewables".

If everyone does this, hopefully the problem will be fixed quickly, plus you can enjoy all the guilt-free AC you want!

throw-the-towel 2 days ago

It's 38 degrees this Wednesday again, and you're talking ceiling fans. This is just ridiculously out of touch.

For the record, I live on a rooftop and it will indeed be 38C this Wednesday at home (Grenoble, France, not a fresh place). No AC, fans, shutters, some shadow and, admittedly, some sweat.

I know I will need an AC one of those years but for now this is fine for home working.

3eb7988a1663 2 days ago

I live in SoCal and am continually shaking my head at the architecture. So my floor-to-ceiling glass buildings in a climate known for sunny weather. So much extra air-conditioning will be spent to cool those buildings compared to if they had been built more reflective.

euroderf 2 days ago

I'd try hanging long sheets of aluminum foil in too-large windows. I imagine someone in academia has studied this.

That works. A lot of people do that in their home when they have no other choice (renting the place, typically).

It'd be better to block the sun before it hits the window though, so that the window itself does not get hot and heat the inside.

Edit: people generally use emergency blankets, fyi. You can stick them to the glass with water.

Timon3 1 day ago

I've read a few times now that applying reflective foil to the inside using water can lead to broken windows - though I can't remember any linking to statistics or studies, so it could also be false or very rare.

I didn't know! Google agrees with you so it must be true.

rrrrrrrrrrrryan 2 days ago

Also windows that go down to the floor has been considered bad architecture for decades.

Wall-to-wall windows are great.

Floor-to-ceiling windows are stunning when you walk into an empty place that you're thinking about buying or renting, but when you're actually living there, windows that go down to the floor create a few feet of dead space. You can't really put any furniture there without feeling guilty about blocking the view you're paying for, and it's uncomfortable to walk up to the edge and look down - it makes you feel uneasy like you're standing on a cliff with your toes at the edge. It's much better for the window to end around waist high.

They're psychologically fine if both the floor and the ceiling extend beyond the window (e.g. it's on the ground floor, and the roof overhangs), but when they're used on every floor in a high rise apartment building, killing limited square footage and driving up energy bills, it's absolute madness.

Danox 2 days ago

Obviously, Mediterranean, Spanish or Adobe type buildings would have been better, and not the northern European style of architecture.

amluto 1 day ago

I stayed in an otherwise lovely flat in northwestern Europe in the summer in an area where the minor heat wave at the time gave daytime temperatures in the mid to high seventies (F) and lows in the sixties. No usable A/C.

If there had been screened windows that opened wide and faced in different directions, it would have been very comfortable by just leaving some windows open for cross-ventilation. Instead it had unscreened high-end “European” windows that could either crack open a bit at the top or could open wide, swinging inward and banging into obstacles (like the bed or anyone’s head who was trying to sleep!). And bugs would come in while the windows were open.

I found this to be rather disappointing.

tokai 2 days ago

Don't worry it will even out when the Gulf Stream chokes out /s

cassepipe 2 days ago

...or not ? As el Nino would say: Porque no los dos ?