Ask Lemmy

If you can afford it, buy a single window AC unit, install it in your bedroom, and then live in there all summer. That's what my parents did when I was little and we lived in a house with no AC. If you can't afford that, a box fan in the window once the sun goes down, then shut it off in the early morning and close/black out the window/draw shades as soon as the sun is up to try and keep the cooler air in that one room for as long as possible.

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.

Passive or Active Ventilation. The idea is to encourage air to pass through the home, which helps with removing heat from inside. Passive Ventilation would be opening windows, using wind catchers, etc. This depends on the design of your home, among other things that you probably don't really have control over. Active ventilation is the same idea, but you use strategically placed fans to induce good airflow. For example, if you have two windows that are opposite to each other, you can place a fan at one window to intake air, and a fan at the other window as exhaust.

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

If your roof is not shaded by trees, a light colored roof makes a huge difference. This can be accomplished a number of ways. Replacing your roofing material with a lighter color is ideal but expensive. Coating it with something like Henry Tropi-cool is durable but the product is also a little pricey. The absolute budget way to do this on an asphalt shingled roof is with a slurry of masonry lime. I've experimented with all of these methods and the results are dramatic. In my case the coating paid for itself within one season and made the house noticeably more comfortable.

Open upstairs windows after 8-9 PM to let cool air in, blackout blinds work really well too

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.

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.

Surprised this hasn't been mentioned yet, but awnings. Glass is a superb thermal conductor. Not even the best curtain in the world would prevent air getting hot through the window if the sun is hitting it directly. An awning is meant to shade the window glass, preventing heating way more than a curtain alone.

Also, if the home has several levels, open the upper floor windows more than the lower ones. Hot air expands and raises. If it has somewhere to escape it will keep the house cool and the windows will draw in wind. Wind moves faster at higher altitudes. That's why attic fans are so effective.

My method is "live in Alaska."

Live somewhere it doesn't get hot.

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.

Only fans.

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.

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.

Close on the sunny side during the day. If the air on the shadow side is cooler, less humid or same as inside, open that side. If your home is more humid or hot than the sunny side, close it just enough to prevent sun ray for entering.

If the heat is not also damp, put wet clothes next to windows or fan for natural refreshment. You can also spray water on your curtain.

Wear natural fiber, coton or lint. Loose clothes, that does cover you body. This way, the evaporation of sweat cools you down. You will also smell much less than if you are wearing synthetic fibers.

Wash your feet, your face, your forarm with water regularly. Do not use cold water, room-temperature or fresh is better but go all the way to the articulation (ankle, elbow), wash inside and outside and let the water dry on you.

Drink small amount of water regularly. Once again not cold.

Keet your heat cover when you expose yourself to the sun. When you get home change out of your clothes that were heated by the sun.

Do not over exercice.

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.

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.

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.

Related

Apparently window awnings make a considerable difference.

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.

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.

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.

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.

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.

Not really a thing you can just do, but thick walls. I live in an old house with double layered exterior brick walls. It has such a massive impact that sometimes I wear a vest inside, while it's heatstroke temperatures outside.