You are forbidden to build a cooling system and no big investment is allowed. Your room is about 27-30 celcius and it takes hours until the room temperature is about 25-26 celcius again, making tiresome sleep. This question is related to Apartment on the top floor gets very hot - cheap, eco friendly ways to keep the place cool? and lifehacks here, summary. The apartment has three floors where the top floor is very hot with sleeping areas. I welcome all kind of alternatives and serious DIY solutions.

What are alternative ways to cool your body in hot room?

  • 2
    This seems more like it belongs on LifeHacks Stack Exchange.
    – Doresoom
    May 9 '16 at 13:02
  • 1
    There is a very similar Lifehacks question: lifehacks.stackexchange.com/questions/11092/…
    – Chenmunka
    May 9 '16 at 14:45
  • @Chenmunka +1 for the finding, yes to some extent -- solutions such as ceiling fan, window tint and blackout light-blocking curtain liners I think belong to Home Improvement. I see threads complementary, not substitutes. It is more accessible to summarise things here, I will add a reference from the thread from home hacks to here so easier to find one another.
    – hhh
    May 9 '16 at 15:46
  • What's the humidity like in your area? May 9 '16 at 22:11
  • @Harper The humidity from day to night has been from 20% to 90% while outside temperature from 2C (36F) to 24C (75F). Currently, there are forest fire warnings in place. The apartments are surrounded by forests so little wind blowing outside. Picture here and more details.
    – hhh
    May 10 '16 at 9:24

Install a ceiling fan (you don't need or want a skylight, as per the other question's answer).

It doesn't matter if it has a reverse switch, it will stir up all the air either way. IMO they don't spin slow enough to use in the winter anyway. If you don't like it blowing directly on you, then do run it in reverse.

Humans cool themselves by evaporating sweat; help it evaporate.

You could just use box fans or oscillating fans, and if that's what you have been doing, and you've never lived somewhere with a ceiling fan in the bedroom, you've no idea what you're missing.


There are lots of variations on the 5 gallon bucket air conditioner. Uses ice made in your freezer and inexpensive fans. Google "5 gallon bucket air conditioner". One example
The basic idea is to load the bucket with ice you've made in the freezer and a fan forces air over the ice - blowing out cold air. If you have a long unattended duration, perhaps a larger bucket would help.

enter image description here

  • 1
    +1 perfect idea, now I need to just freeze a lot of small pieces of ice and get a container. For lasting the night, 5m x 5m x 2m = 50m^3 room of air at 28C to 22C requires abot 8kJ. 1 kg of water 4.19 kJ/kg.C so 6C=8kJ/(4.18kJ/kg.C)*m=2*C*m/kg so 3=m/kg i.e. I need 3 kg of ice at a time pont to cool down the room. So I need many pieces of ice for night. I like this model because it only destroys the lid, I have a big fan so probably no need for the lid to just cool down the room.
    – hhh
    May 9 '16 at 10:15
  • 2
    Remember that this will make your fridge work harder, and pump out the amount of heat taken out of the ice, plus some extra for inefficiencies. I hope your fridge is far away. May 10 '16 at 10:39
  • 1
    Big problem with this. Your fridge is working harder and it's filling the room with more heat than the ice removes. So it's a net lose unless you make the ice at times of the day you want to heat the house. May 10 '16 at 21:41

It sounds like outside air is perfectly cool once the sun goes down. So you're dealing with solar gain, that's when the sun shines on an enclosed structure and makes it hot. That's how babies and dogs die if left in hot cars in the summer. At dusk the building is no longer heating up, but it has some thermal mass, so the heat is sticking around.

The time to act is dusk, when the sun is no longer adding heat faster than you can remove it. It sounds like outside air is perfectly cool, so I would use fans on exterior windows to pull in/pull out as much air as possible to cool down the house.

If humidity is low, you may also be able to use evaporative cooling ("swamp cooler" type gadgets) to cool the air.

You can also reduce solar gain in the first place by painting the roof white, and if possible, west/south facing walls. You want the highest reflectivity white the store carries.


I list options besides cold shower.

Alternatives ways

  1. blackout light-blocking curtain liners and it alternatives such as rescue folio

  2. window tint requires adhesing them to the window

  3. satin/silk clothes, satin/silk bed linens (they do not attract dirt and positive charges)

  4. if your body is heating up due to allergies, inexpensive negative ioniser can for example alleviate asthmatic symptoms

  • 1
    A cold shower will lower your core temperature and increase your metabolism; not sure if that's the right way to go (especially before bed time, unless you're a fast sleeper).
    – Mazura
    May 8 '16 at 21:05

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