How do you plan to cool down your apartment this summer?

First line of defense: blocking out sunlight in all windows during the day

Second line of defense: highly active drafting, creating a cross-breeze when the outdoor temperature is lower than the indoor temperature

Third line of defense: Fan, reduces perceived temperature significantly

Fourth line of defense: Acclimatization, warm showers before bed (supposedly helps)

Fifth line of defense, in case everything else fails - basically a heatwave: portable AC

Obligatory Technology Connections video on awnings https://youtu.be/uhbDfi7Ee7k
- I wish I could have some installed, but alas, I live in an apartment building on a high floor, and I don't get to make the call.

Basically keeping all the windows open through the night and closing them in the morning. I also sleep upstairs directly below the roof during the colder months, but move to the ground floor in summer, where it gets much less hot.

Things will creep in at night, I mean spiders not Nosferatu. Although maybe Nosferatu. You don't often hear a monster work the word enmity into a sentence.
- Funny you'd say that, as we actually get what we call "Nosferatu spiders" in Germany quite often in our house. I don't really mind them though, the occasional mosquito is much more annoying. We have nets on some of the windows though.
- I didn't mean for Pyotr to be my roommate but it just kind of happened. He's pretty chill though. My place used to be pretty messy but he cleans it while I sleep. He's totally silent too so I don't even wake up! Really the only downside is the anemia but I'm taking iron supplements now and that might help a bit.
Yep plus blackout blinds throughout the day, they massively help.
- And/or blackout curtains as well. They pull double duty as an insulating layer, not just blocking light.

Fan.

+1
We use that too. It's less impactful than using a clim and it's still enough for us.

If you have a roof, you can put a sprinkler on it and spray water with a tap timer. Just enough to wet it, so that the water can evaporate and cool the roof.

If you have windows facing the sun, get blockout curtains and close them before the sun hits them.

If your front door has a window, get an expanding shower rail and hang a blockout curtain.

If you have internal doors, keep them closed.

Wear clothes made from natural fibres.

Drink extra water.

Move slower.

Eat cold meals, like salads, rather than cooked meals that heat up your home.

Install a ceiling fan and keep the air moving.

When the sun is off a window, open it to encourage ventilation.

Keep air moving at night.

Put a thin cover on your bed.

Have cold showers.

Source: I live in a hot climate.

The A/C

I lived in an apartment without an ac and I also wasn’t allowed to install a window ac.

I ended up buying a portable ac which got the job done well enough. They’re not perfect but they’re miles better than open windows with box fans.

We open the windows when the temperature dips, especially at night. If the wind is low or dead, we will use a fan to push the hot air out of one window so cool air gets pulled in though the rest of them.

We have a portable AC in the main room and a window AC in the bedroom for when it gets too hot during the day, or doesn’t dip at night.

If you live in a dry climate, a swamp cooler could work.

It really just depends on your climate, geography, and infrastructure.

Where is I was raised, it would be consistently 90-100 Fahrenheit throughout the summer. And one week that was always up to 110.

I had no ac, but a constant broken swamp cooler. So basically no real ac.

In the mornings and night when it did become cool, you would open all the windows and doors for the air and wind to blow through, and then about 9am you would close the windows and blinds and deal with the heat.

Sleeping through the worst parts of the heat is not a bad idea.

How's the humidity where you live? If you live in a dry climate, a swamp cooler might be a good option.

If you live in a humid climate, window units or portable AC's are better than nothing. A long time ago, the only AC I had was a window unit in my bedroom. It was miserable overall but at least I had someplace I could go to stay cool and sleep comfortably at night.

Not strictly cooling the apartment, but I keep a large supply of ice cold water ready to drink whenever I start to get too warm—if you can effectively cool yourself throughout the day, it raises the maximum comfortable temperature of the apartment as a whole, and it’s usually easier to cool a single body than a large volume of air.

Fans. Fans everywhere. Sometimes ice packs. I invested in a portable ac last summer and that helped for my bedroom. I pretty much made that home base for the hottest parts of the day.

Thankfully I live near the ocean so I'll be in there a bunch.

AC mainly. I have a ceiling fan as well.

Last year we swore we were going to by an AC. We didn't.

This house was built in 1880, it ain't happening. During the hottest part of the day I'll be at the pool or the library.

I'm in an area that cools down at night so i use that as much as possible:

Once daytime temps drop below indoor temps (usually late evening) i open all windows and arrange a couple fans and run them on low all night. My goal is to move all of the hot air out of the apartment and replace it with cool outdoor air.

In the morning, ideally just before sunrise, i draw most/all curtains, shutter blinds, close windows, and turn off all excess lights. During the day i keep everything closed and the air still, and use as few lights as i can manage.

I can generally maintain about 15 degrees (f) cooler indoors with this technique. I currently live on the third floor which is working against me; this was much more effective (20-25 degrees) when i lived on the ground floor.

If i leave the windows open it or worse forget to draw the blinds it gets much warmer indoors than outside. I think my building must have pretty mediocre insulation and my windows are all single-pane.

I live in Ireland. I'll probably have my heating on during the colder nights, and I'll check the roof for leaks once per week or so.

I am curious, why do you need to check for leaks so often?
- We often gave high winds and rain. Last month, a wind storm damaged loads of roofs in my neighbouhood, and some people only noticed after the leaks started.
  In addition, construction in Ireland is notoriously bad, and one of the first things we did was to fly over a family member who has decades of roofing experience, and he fixed potential leaks. Just as well, as we have neighbours who already had to change some of their timber supports that started rotting. We are still pretty paranoid about the roof quality, though.

Open the windows at night. It's more efficient if you have blinds and can close them to prevent the sun to heat the windows during day

Uhh, I live in the southern hemisphere and I mostly ate popsicles (not all the time, they are very sugary) and kept my ceiling fan on. I would also recommend colder and more frequent showers and drinking cold water.

Also, I guess you could try getting a fan and putting a bag of ice behind it, I do not know if that would work but someone I know did that during summer.

On an unrelated note, I probably won't need to do absolutely anything for winter here since it doesn't get very cold.

I'm saving and planning to pay a $900 electricity bill in August.

Window units are a thing, and I recommend you get one.

I'm on the top floor of a poorly-insulated midrise, and summers are absolutely miserable. I have a window AC in the bedroom, otherwise it's all ceiling fans and ice packs. I bought a few "pillow insert cooling pads" (basically a Chillow) and just put them on my neck or in my shirt during the day. Frozen water bottles also help.

I run the AC if it's really hot but that only cools down the downstairs. Upstairs where I sleep I just basically have a fan running all summer pointed at the bed.

Air conditioner

Fan across a crappy solar panel setup made from scrap. Power is way too expensive over here.