this post was submitted on 27 Jun 2025
90 points (98.9% liked)

Ask Lemmy

32822 readers
1396 users here now

A Fediverse community for open-ended, thought provoking questions


Rules: (interactive)


1) Be nice and; have funDoxxing, trolling, sealioning, racism, and toxicity are not welcomed in AskLemmy. Remember what your mother said: if you can't say something nice, don't say anything at all. In addition, the site-wide Lemmy.world terms of service also apply here. Please familiarize yourself with them


2) All posts must end with a '?'This is sort of like Jeopardy. Please phrase all post titles in the form of a proper question ending with ?


3) No spamPlease do not flood the community with nonsense. Actual suspected spammers will be banned on site. No astroturfing.


4) NSFW is okay, within reasonJust remember to tag posts with either a content warning or a [NSFW] tag. Overtly sexual posts are not allowed, please direct them to either !asklemmyafterdark@lemmy.world or !asklemmynsfw@lemmynsfw.com. NSFW comments should be restricted to posts tagged [NSFW].


5) This is not a support community.
It is not a place for 'how do I?', type questions. If you have any questions regarding the site itself or would like to report a community, please direct them to Lemmy.world Support or email info@lemmy.world. For other questions check our partnered communities list, or use the search function.


6) No US Politics.
Please don't post about current US Politics. If you need to do this, try !politicaldiscussion@lemmy.world or !askusa@discuss.online


Reminder: The terms of service apply here too.

Partnered Communities:

Tech Support

No Stupid Questions

You Should Know

Reddit

Jokes

Ask Ouija


Logo design credit goes to: tubbadu


founded 2 years ago
MODERATORS
 

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 !

all 48 comments
sorted by: hot top controversial new old
[–] CanadaPlus@lemmy.sdf.org 2 points 15 minutes ago* (last edited 6 minutes ago)

I was also wondering if plants could also help inside, any ideas ?

They shouldn't. Plants can raise humidity, but they have no power to break the the laws of thermodynamics. Once heat is in your house you can only really move it out of your house; there is no destroying it in place. Note this does not apply to plants just on the outside of your home, like on a roof.

Watch your use of appliances carefully. Even a fridge generates heat - it might be better to place it outdoors or semi-outdoors if you're going to be really hardcore about your approach.

A better insulated house will keep heat out as well as cold, so all usual tips on building or renovating your envelope apply.

[–] Ofiuco@piefed.ca 3 points 1 hour ago (1 children)

Sorry about the content in spanish, but some years ago there were news about someone placing agave or some succulents/cacti in people's roofs, since some species "absorb" the heat, something along those lines.
Here https://youtu.be/BOjYB7qaESE

Also this plant seems to help refreshing the room in general
https://wikipedia.org/wiki/Dracaena_trifasciata

I haven't tested them yet since I am just growing my little garden on the roof of my house, but hope something of that helps.

[–] dumples@midwest.social 3 points 1 hour ago

Pretty much anything on a roof will cool you down. The soil which will contain water is slower to heat while the plants will be be absorbing solar energy and "perspiring" to cool you down.

Locations under large trees can be locally up to 10 degrees colder in the summer and 10 degrees warmer in the winter.

[–] dumples@midwest.social 2 points 1 hour ago

Curtains are a god send. Make sure you have them to isolate things coming into and out of your house. So have a curtain to isolate your entry way. That way the heat stays there. Same things at the stairs so you can keep the cool in the baseline while you stay there

Also to note that depending on your house and the outside temp its not worthwhile to open the windows at night. But generally it is better. Make sure you have a fan in the window blowing the hot air out as well. Its best if its upstairs to draw the cool air in.

[–] RodgeGrabTheCat@sh.itjust.works 3 points 1 hour ago (1 children)

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.

[–] CanadaPlus@lemmy.sdf.org 2 points 12 minutes ago* (last edited 5 minutes ago)

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 is)

[–] JubilantJaguar@lemmy.world 31 points 6 hours ago (2 children)

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.

[–] starlinguk@lemmy.world 3 points 2 hours ago* (last edited 2 hours ago)

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.

[–] th3dogcow@lemmy.world 16 points 5 hours ago (1 children)

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.

[–] JubilantJaguar@lemmy.world -3 points 4 hours ago (2 children)

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.

[–] starlinguk@lemmy.world 2 points 2 hours ago

My office in Southern Germany doesn't have AC, even though it should. It's the hottest part of Germany.

[–] th3dogcow@lemmy.world 3 points 4 hours ago* (last edited 4 hours ago) (1 children)

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.

[–] JubilantJaguar@lemmy.world 0 points 4 hours ago (1 children)

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.

[–] th3dogcow@lemmy.world 3 points 4 hours ago

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.

[–] bluGill@fedia.io 18 points 6 hours ago (1 children)

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.

[–] starlinguk@lemmy.world 0 points 2 hours ago* (last edited 2 hours ago) (1 children)

People in hot climates do not sit outside. They also do not open their windows. Because they're not insane.

[–] CanadaPlus@lemmy.sdf.org 1 points 9 minutes ago

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.

[–] LogicalDrivel@sopuli.xyz 3 points 4 hours ago

I put foil insulation on some of my bigger windows in the summer. Especially southern facing windows (in northern hemisphere). That mixed with tons of fans and the occasional cold towel when needed helps tremendously.

[–] d00phy@lemmy.world 12 points 6 hours ago (3 children)

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.

[–] HEXN3T@lemmy.blahaj.zone 3 points 1 hour ago

My parents' house has one, and every house needs this.

[–] jubilationtcornpone@sh.itjust.works 4 points 4 hours ago (1 children)

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.

[–] trailee@sh.itjust.works 3 points 3 hours ago

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.

[–] bluGill@fedia.io 6 points 6 hours ago

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.

[–] cloudless@piefed.social 52 points 10 hours ago (2 children)
[–] GaMEChld@lemmy.world 12 points 9 hours ago

ᕕ( ᐛ )ᕗ

[–] Boxscape@lemmy.sdf.org 5 points 8 hours ago
[–] susi7802@sopuli.xyz 49 points 10 hours ago

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.

[–] trd@feddit.nu 7 points 7 hours ago

Drink alot of water, then try to pee in the air and catch it with your mouth, all the sudden the heat is the least of your problems.

[–] Quilotoa@lemmy.ca 3 points 5 hours ago (1 children)

As a northern Canadian, I kinda chuckle at the need for an air conditioner. Of course, my punishment in winter.

[–] CanadaPlus@lemmy.sdf.org 1 points 7 minutes ago* (last edited 5 minutes ago)

They're becoming more common in the populated areas of Canada, although it's still a minority that has it where I live as well.

Climate change is really obvious at this point, and the smoke is awful...

[–] GaMEChld@lemmy.world 22 points 9 hours ago (1 children)

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.

[–] Elaine@lemm.ee 4 points 4 hours ago

Thanks, I went down a rabbit hole reading about wet bulb temperature.

[–] napkin2020@sh.itjust.works 13 points 8 hours ago (1 children)

Related

Apparently window awnings make a considerable difference.

[–] Cenzorrll@lemmy.world 1 points 26 minutes ago

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.

[–] Goldholz@lemmy.blahaj.zone 5 points 7 hours ago (1 children)
[–] starlinguk@lemmy.world 2 points 2 hours ago

At night. Not when it's 40C out.

[–] psx_crab@lemmy.zip 18 points 9 hours ago (1 children)

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.

[–] JayGray91@piefed.social 10 points 8 hours ago (1 children)

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...

[–] psx_crab@lemmy.zip 5 points 6 hours ago

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.

[–] karpintero@lemmy.world 10 points 9 hours ago* (last edited 9 hours ago)

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):

  1. Replacing the insulation in the roof/attic. You could also add radiant barriers, but insulation is probably a better bang for your buck.
  2. Insulating the exterior walls (drill and fill). Our walls used to be hot to the touch in the summer before this.
  3. Double pane windows
  4. Seal any air gaps or holes. Expanding foam is pretty good at this.

From what others have told me:

  1. Installing a whole house attic fan to evacuate hot air at the end of the day. My neighbor did this and swears by it.
  2. Painting your house a lighter color. Can't say how effective but makes sense intuitively.

Stuff that only sort of worked:

  1. Swamp coolers. Works ok in a pinch, but your house will feel humid like the tropics. Would personally skip.
  2. 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.
[–] schmorpel@slrpnk.net 11 points 10 hours ago

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.

[–] untorquer@lemmy.world 7 points 9 hours ago

Using a reflective surface such as aluminum foil on the windows (shiny facing outside) will help. I've used contact spray adhesive on cardboard cut to size of window before. You can also get the bubble-wrap aluminum insulation.

Cut temps in my old studio from food-safe poultry temp to near ambient on the 100+F/40+C days.

[–] Hoohoo@fedia.io 5 points 9 hours ago

Blackout curtains on the sunny side reduce a lot of daytime heat.

[–] acryline@framapiaf.org 5 points 10 hours ago

@salcie
On m'a parlé des films solaires adhésifs anti chaleur pour les vitres. Mais, je ne pourrais pas conseiller de marque.

[–] fistac0rpse@fedia.io 3 points 9 hours ago

move to Alaska?

[–] BurgerBaron@piefed.ca 3 points 9 hours ago

Didn't say if you own the home or not, but if so:

Mind it's only hot for 2-4 months out of the year for me, so I have a winterized attic fan. Just means I'm not losing heat in the winter and paid a little more to buy it. You can just get a regular attic fan if it's never or rarely cold where you live.

You leave windows open, but now there's negative pressure from pushing air out the attic where a lot of the heat is trapped and sucking in air from outside even if there's no breeze. I leave the attic access hole open when it's running. The rare day I still use a Window A/C to sleep.

[–] nivenkos@lemmy.world 0 points 7 hours ago

Just get AC, it works so well for de-humidifying too.

But otherwise blackout curtains can help a bit but also radiate heat themselves.