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 !
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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
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.
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
This works really well. I also open the downstairs windows. The hot air going up and out creates a draft effect, sucking in cold air from the downstairs windows.
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.
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.
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.
I gain weight this winter. I have such a trouble cooling down the part of my body that gain the weight. It is hard…
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.
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.
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.
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.
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)
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.
