Hi there, time to share ways to keep your home cool during hot times
So ok, usual ways I use:
- open everything during night
- close everything during day
- external sheets on windows without shutters
- some curtains to prevent heat from going upstairs
I was also wondering if plants could also help inside, any ideas ?
Share your advices !
You must log in or register to comment.
Having lots of trees around the house will keep it cool but cause lots of other problems. Solar panels and AC is the way to go.
Only fans.
ᕕ( ᐛ )ᕗ
Only fans.
Most importantly: Make sure no direct sunlight enters the house. Insulate your roof. Plants in the house can have a modest cooling effect. Close doors to rooms that get hot faster. Lower floors (especially cellars) are cooler, with a small ventilator this cooler air can be transported upwards. At night, use small ventilators to “pump” cool night air through all the floors.
Lose weight. I’m totally serious. Thin people have much higher natural tolerance for heat.
It’s no coincidence that so many developed countries have become addicted to AC. The fact is that most people there are now overweight and in many (USA most obviously) over 40% are literally obese. Conversely, AC is much less common in places like France and Japan, and it’s not just because they’re too cheap.
If you want to stay cool in a heatwave, it helps not to be wearing a blubber overcoat that you can’t remove.
Conversely, AC is much less common in places like France and Japan, and it’s not just because they’re too cheap.
This is completely wrong. Like 95% of all households in Japan have ACs. Even on the countryside. I was living in Japan for a year and the only time I visited a house without an AC was on an island with 1000 inhabitants.
in places like France and Japan
This is completely wrong.
You talk exclusively about Japan, so even if your anecdata is representative, then my point is not “completely” wrong. Let’s begin by using language correctly.
If youre making a point and part of it is a lie, it is completely wrong.
Lets begin by growing a pair of balls and owning up to your mistakes instead of hiding behind condescension.
Conversely, AC is much less common in places like France and Japan, and it’s not just because they’re too cheap.
I assure you that practically every household in Japan has an air conditioner these days. Maybe not some decades ago but things have changed, including the climate. And companies are legally required to keep offices at no higher than 28°C, too.
Offices in all countries have AC, the question is about homes. I doubt “practically every household” in Hokkaido has AC. Here in northern Europe, very few do.
Every home I have visited in Japan over the past two decades has had A/C units. You may be right that in regions where it is very cold an A/C unit may not be necessary. However, as heat pumps are one of if not the most energy efficient ways to not only cool but also heat a home, I wouldn’t be surprised to find them even in colder regions.
Add on the fact that houses in Japan are generally considered a depreciating asset, so until recently demolitions and new construction were favored over renovations, I stand by my first statement.
Additionally, every place I have ever rented has come with at least one A/C unit, and additional holes are predrilled in other rooms so that split systems can be installed.
Fair enough. Most of Japan is hotter in summer than northern Europe. Here it has been 35C for much of the last week and domestic AC penetration remains extremely low. There are also quite few fat people, and the two things are probably at least a little bit connected.
I don’t disagree that people who are overweight will feel hotter. The rainy season makes it feel hotter than just the temperature here, too. Buildings here are probably more poorly insulated, too.
My office in Southern Germany doesn’t have AC, even though it should. It’s the hottest part of Germany.
Give it a couple of years and a few more heatwaves! This is the insidious problem with heatwaves, as I see it. Tolerance for heat and cold is in large part cultural - go to Portugal in winter to see how tolerant people can be of cold indoor temperatures. But with every new 3-day heatwave, Europeans are going to rush out to buy AC units to escape the immediate misery. Next thing we know the continent will be like the US, where it’s just unacceptable for indoor temperature to be outside the 19-23C range. And mass AC is just a climate disaster. That’s my worry.
This may explain why I’m wearing a hoodie in the office in late June while most everybody else is comfortable or still hot.
But, I also do lots of outdoors stuff and acclimate to heat up to a point.
AC is much less common in places like France
It’s everywhere around me (in France) because it’s becoming too hot, whether people are fat or not.
How is losing weight going to help right now? They can hardly lose enough weight in time for the next heatwave.
Or maybe they’re in the menopause.
Or maybe it’s 50C out.
Or maybe they’re on one of the plethora of medications that causes heat intolerance.
Or maybe they’re elderly.
AC is horrifically expensive (energy bills) and terrible for the environment, by the way. People aren’t cheap, they can’t afford it.
I found it good advice. We don’t know every detail about OP life. Of course, some example won’t apply but that’s fine.
I gain weight this winter. I have such a trouble cooling down the part of my body that gain the weight. It is hard…
I mostly agree since it’s healthy either way, but back when I was half my weight when I studied in a 4 seasons country, coming back to the year round hot and humid home country still makes me immediately sweat the moment I step out of the plane. Constantly felt like I always have a blanket on me. Anecdotal for sure, but I just want to say my piece.
Not disagreeing but none of my kids are at all fat and one is so hot-natured, it’s not always just insulation. One of their cousins, too, she was just never cold and always hot.
I did always joke with my ex that I was built spare because I am from the hot part of the world, and he was padded because he was from Michigan.
Interesting anecdotes! There’s actually a bit of truth in the last one, I believe. Bodily fat is more evenly distributed in Inuits and even Europeans than it is in, say, west Africans.
If you live in a humid area, AC will become more and more valuable. Wet bulb temperature. At some point your sweat will no longer evaporate and you’ll die. Climate change cometh.
Thanks, I went down a rabbit hole reading about wet bulb temperature.
Yeah, this recent heat is expected to cause deaths. Not only because of the heat itself, but because of the humidity. Humans can tolerate extremely high +100°F temps when it’s dry… But when you start cranking up the humidity, that tolerable temperature quickly begins to drop. At 100% humidity, that tolerable temperature is only in the mid 80’s. Above that point, even the best fans won’t help cool you. Because fans only work by evaporating sweat, and in high humidity that sweat doesn’t evaporate.
Look at old hot climates.
notice the afternoon siesta. Sleep in the shade in the hot of the day and work (play) later into the night.
notice large covered porches around the house. Spend more time outside in the breeze and shade.
notice the large windows and doors. When you are inside get plenty of ventilation-
notice the ceiling fan (often slave pulled). Be glad we now have electric fans.
notice the folding hand fans. Portable fans exist, though most of the time the hand fan is better - get one.
People in hot climates do not sit outside. They also do not open their windows. Because they’re not insane.
In hot and dry climates, a breeze in a shady place works well, actually. In humid places it’s harder.
That actually has results counterintuitive to temperate people when it comes to clothing. Arabs don’t just cover up for modesty.
Huh? I sit outside, with a fan on, in up to 35/95F in the shade. And it’s humid here. Outside hot does not feel as bad as inside hot, and you do learn to be still and cool enough. It is not weather to go running, but sitting, in the shade, with a fan? No problem.
they do open windows. They also close them. When they do that depends on the situation.
livewise they sit outside at times. They also sit insides.
There are many different hot climates with different situations. You cannot make a blanket statement. And you cannot look at what they do today when ac is common to figrue it out (where at is common)
Apparently window awnings make a considerable difference.
I have a large room with clear story windows and the entire south wall is windows, in the desert. The roof extends out far enough to block the sun in the summer, but not in winter. In winter during the day it’s 90F when it’s below freezing outside. The amount of heat trapped from the sun coming in through windows is no joke.
I was searching to see if someone had posted this already because that was exactly what I wanted to contribute. Excellent work!
As someone from the equator with hot and humid air, this thing is common, it allow hot air in the attic to escape so the hot attic won’t radiate into your house, while sucking fresh air into your house. Plant surrounding your home exterior also will help with the cooling as well, especially when it stop light from hitting your wall. I usually just open everything during day, but open everything during night will also help circulate the hot air heated by the heat-trapping concrete wall. As of now i can’t open during night because my cat will escape, so i just use ac for half hour or so.
as someone from a similar place, mosquitoes make opening windows at night a health hazard, unless you install netting.
I should be getting to do that…
Yeah the mozzy mesh is a life saver, for both mosquitoes and flying termite/ant swarm after rain, but do keep in mind that meshes will restrict some air flow. Still, it’s better than nothing, and combine with that rooftop onion you might get better result.
I never knew what that rooftop onion does. But now that I know, that’s another thing to fix.
Pretty good (but long) answer with historic solutions here : https://solar.lowtechmagazine.com/2025/06/dressing-and-undressing-the-home/
My short answer : do not let the sunshine in (stores, awnings, shutters), let it flow let it go (air), I like big walls and I cannot lie
Came here to point to this.
Also, if outside noise is preventing one from keeping the windows open over night, get custom-fitted silicone earplugs.
Something I haven’t seen mentioned is an attic fan. They’re mounted on the ceiling of your highest floor. These used to be common before AC became so widespread. Basically, you open your windows, and the fan sucks air in through the windows, through the house and up into the attic, where an exhaust fan can push it out.
They were mostly had such poor insulation as to be not worth having because of the losses in winter. There is a good reason most people hove tore them out when they get ac.
My parents’ house has one, and every house needs this.
Second this but wanted to add that a remotely mounted fan (one that’s connected to the intake vent through a duct rather than being mounted directly in the ceiling) significantly improves the experience because it cuts down on the noise and minimizes heat losses in winter.
We have a gable mounted attic fan that draws air through the house. 5000 cfm makes for a nice breeze.
Gable-mounted still incurs direct vibration into the structure. I have a QuietCool whole house fan that is suspended in midair from the gables, to reduce that vibration and noise, while being ducted from a framed opening in the hallway ceiling.
Whole house fans are pretty great during the right season, but you need to be aware of the humidity level outside or you can make things worse even if seems cooler at the moment. I also have central AC that gets run either when it’s too humid or too hot at night. But overall I’m very happy with the whole house fan and only having moderate insulation - the house resists heat incursion during the day and then we can quickly cool things down in the evening without using too much electricity.
When its hot, avoid cooking indoors if you can. Especially iff you dont have proper exhaust in your kitchen. Buy some food that require less heat or none. Sandwiches, Fruits, Salads, etc.
Keep your home cool and yourself too.
Wet curtains, and if that’s not enough a wet towel on the head (not your home, I know, but something to remember when your brain threatens to overheat and you’ve got no energy left to pursue another solution.
Just keep in mind this only works if the humidity where you live is on the lower side. If you deal with high humidity where you live you won’t experience nearly as much cooling from those wet curtains or the old wet towel over a box fan trick.
The towel on your head still works though because it’s on a much smaller scale unless you’re dealing with near 100% relative humidity. Double that with a fan of some type and you’re in business.
Thanks for adding that info - something I’m less aware of, luckily I live in a dry climate where water helps.
No problem! Excessive humidity just sucks in general for us since our main cooling system (sweating) relies on the sweat being able to evaporate. Higher humidity means the air is already full of moisture, so evaporation slows way down and is significantly less effective.
Air flow was key. Tried to get a good cross breeze from one end of the house to the other (unless the breeze is also hot). At night, we’d use a box fan in the window or door to get all the hot air out. If you can block your exterior walls/windows from getting direct sunlight, that should help. Curtains work (or you could also just place objects or plants in front to block the sunlight). Alternatively, you could install one of those large roll up sun shades for a more permanent solution. Did that for a few windows that get a lot of sun and made a big difference.
From personal experience, the following made a difference (but some will have a lot higher cost):
- Replacing the insulation in the roof/attic. You could also add radiant barriers, but insulation is probably a better bang for your buck.
- Insulating the exterior walls (drill and fill). Our walls used to be hot to the touch in the summer before this.
- Double pane windows
- Seal any air gaps or holes. Expanding foam is pretty good at this.
From what others have told me:
- Installing a whole house attic fan to evacuate hot air at the end of the day. My neighbor did this and swears by it.
- Painting your house a lighter color. Can’t say how effective but makes sense intuitively.
Stuff that only sort of worked:
- Swamp coolers. Works ok in a pinch, but your house will feel humid like the tropics. Would personally skip.
- Portable AC. The exhaust hose gets hot so it’s not as efficient as an external AC or window unit. But it could help if you’re directly in front of the cold air vent.
Painting your house a lighter color. Can’t say how effective but makes sense intuitively.
Probably makes a big difference. I just measured my patio, grass and driveway temps today with an infrared themometer. Grass was 109, patio was 123, and the blacktop was a whopping 148. My wife has been talking about using a cream or neutral gray finish on the driveway, and a 20 degree difference is definitely worth it.
Yep, it’s a low-tech decision that’ll pay dividends. Same reason I’d opt for a white or lighter colored car if it’s going to be parked outside.
Should’ve also mentioned roofing shingles as well. See a lot of houses with dark roofs just soaking up sunlight.
Years ago I was watching Doomsday Preppers and one fella dug a long trench, 100 foot if I’m not mistaken.
In the trench he laid a large PVC pipe and filled in the trench. At the far end of the pipe there was an air inlet. He ran the pipe into his basement and up inside a wall with an inline fan. Cool air, as well as fresh air.
Didn’t do anything for the humidity, I suspect.
He claimed it worked, I can not confirm.
It does make since as it’s about 4c/39f four feet/1.2m underground.
So DIY ground source heating/cooling, basically.
I suspect that’s not long and deep enough, but if it is, it will produce air at the local year-round average temperature, at all times. (Whatever that happens to be)
Thats basically how earthships are cooled. You can also run the pipe through an evaporative cooler to cool the air even more.
You can also run the pipe through an evaporative cooler to cool the air even more.
At some point there, you’ve just reinvented AC.
Only if you use a better working fluid and add compression and expansion steps, but a long pipe in a ditch filled with water isn’t what I would call AC quite yet.
Aren’t there AC systems that just evapourate water from municipal supplies to the atmosphere?
I mean, yes, I’d agree that blowing air over a standing water body isn’t AC, but we’re getting close.
You’re thinking of a swamp cooler. In some places they work great, in other places they’re next to useless.
Air conditioners are called that because they “condition” the air by not just cooling but also by reducing the humidity.
Ah, okay. So not technically an AC unit then.
As another person stated, that’s an evaporative cooler or “swamp” cooler.
AC works by “moving” heat energy from one place to another by way of the refrigeration cycle. This helps you feel comfortable by both cooling the air and also as a byproduct it removes humidity from it. If you want a nice long video on how that works just search “technology connections air conditioning” on YouTube and enjoy. Very informative.
I think on a purely technical note, Air Conditioning goes beyond just cooling the air and involves reduction of humidity. Personally, I wouldn’t consider it AC because you’d have to keep refilling the evaporator resivor, instead of just powering the device, but that is a nitpicky item that isn’t technically a requirement.
Probably not exactly the answer you’re looking for.
If you have access to sun and are tech savvy, hop on Facebook market place or equivalent. You can probably get very cheap used solar panels that still have plenty of output. Rig up a AC unit in one room and cool just it.
