8 ms·

How to Sleep Comfortably on a Hot Night

50 points by 321abc 17y ago

ojbyrne 17y ago
Air conditioning is a wonderful thing. And, often, cheaper and more environmentally friendly than the things described here.
- dmoho 17y ago
  Here are most of the suggestions from the link: - Have fan with a pan of ice in front if it pointed towards you - Keep a damp hand towel on your forehead - Put an ice pack under your neck - make a rice sock, put it in the freezer and then inside of your pillow - sleep nude - sleep in a 'spread eagle' position - take a cool shower, wet your face, run your wrists under the cold tap Please correct me if I'm mistaken - How does an air conditioner use less energy than a fan turned on for the same amount of time? I did a quick search and most of the hits say that air conditioners use more power. (Here is one of the links that came up: http://www.todaysgreenconstruction.com/2008/07/battle-green-fan-vs-air-conditioner.html http://www.todaysgreenconstruction.com/2008/07/battle-green-...).
  - calambrac 17y ago
    You had to expend the energy to freeze the water. You probably did that with a freezer, which runs using a compressor just like an air conditioner, except that it has to get a lot colder. I think you're still right that it comes out cheaper, though, because you'd be spending most of the freezer's energy output anyways.
    - jacquesm 17y ago
      The freezes compressor will run longer if you stuff it with things that are not yet at the temperature of the rest of the stuff in the freezer. This is also why it is a good idea to de-ice your freezer every now and then, keeping all that ice at a low temperature against the leakage through the walls of the freezer costs energy.
      - Elepsis 17y ago
        I'm not so sure this logic makes sense -- in fact I think it might be entirely backwards. I've always been under the impression that though you pay a penalty for freezing things the first time you put them in, thereafter a full refrigerator (and freezer) is actually much more efficient because it's more difficult to keep air cold than it is to keep any variety of items that are more dense. If we're talking about leakage, too, air obviously exits the freezer much more often than its contents do.
        swombat 17y ago
        Air has a very low heat capacity. It doesn't take much energy to cool a cubic metre of air quickly (see air con, for example). On the other hand, cooling a cubic metre of water and other watery solids takes a load more energy. In terms of keeping it cool, that probably depends on how good your freezer's insulation is. If it's really good, it probably doesn't take too much energy to keep things cool (air or otherwise). If it's not so good, you'll incur a constant "your freezer sucks" tax. In the case being discussed, we're talking about freezing stuff every day, and letting it thaw in/near your bed during the night. So the cost would definitely be there.
        calambrac 17y ago
        No doubt there's still an additional cost, I just don't think it would be high enough to make it more expensive than running an air conditioner, given that you're going to be running the freezer regardless (depending, of course, on how much we're talking about. I'm picturing a window unit vs. a window fan with a baking pan's worth of ice). Any ideas on how to be more rigorous about thinking this through or running an experiment?
        swombat 17y ago
        You could take a certain quantity of ice, figure out how long it takes to melt under a fan in hot weather, then calculate the energy required to get that quantity of water into ice (heat capacity equations), and you'd have a rough figure for energy spent per unit time. Then compare that with the energy consumption of an air-con unit.
  - phreanix 17y ago
    Let me get this straight, you're asking how an air conditioner uses less power than a regular fan? While I can't cite any wattage/amps/etc. figures, an air conditioner runs several things besides a fan motor, most notably its compressor. The more advanced ones also have other electrically driven parts, like a thermostat. As for real world stats, when I lived in the Philippines, I can say for a fact that running a fan vs an airconditioner makes at least a 60-70% difference in my electric bills.
mannicken 17y ago
When it was 40C+ here in Seattle a couple of weeks ago, I simply went outside and slept there in a nice cool 30C+ weather. If you have computers and electricity, by 10-11pm it will be significantly cooler outside so if you have a deck or roof or backyard, try sleeping there.
brianto2010 17y ago
Better idea... http://lifehacker.com/5335024/how-to-build-a-diy-dorm+legal-ac http://lifehacker.com/5335024/how-to-build-a-diy-dorm+legal-...
- windsurfer 17y ago
  I highly, highly doubt that would actually work. You would be much better off taking advantage of evaporating water somehow, such as putting a light damp cloth in front of a fan or something else. The problems with that design are highlighted in the comments, but it mostly comes from really not having enough surface area.
  - brianto2010 17y ago
    Care to explain? I am not good at science/physics.
jrockway 17y ago
I think most of these suggestions just give you something to do while you make yourself sleepy.
edw519 17y ago
Many of these ideas are variations of an evaporative or swamp cooler. They work great west of the Rockies because of the lower humidity. They don't work very well at all east of the Rockies. Try a fan with some ice in August in Miami. You won't be hot. You'll be hot and wet. Better to just turn on your ac.
hooande 17y ago
Any YC founders who spent the summer in Boston know that this information is very valuable. Bookmark this one in case YC moves back out there and you have to borrow an air conditioner from Jessica.
bootload 17y ago
"... How to Sleep Comfortably on a Hot Night ..." hotest it got here in Melb last year was 46C and multiple days above 43C with extreme fire weather ~ http://www.flickr.com/photos/bootload/sets/72157614397725714/ http://www.flickr.com/photos/bootload/sets/72157614397725714... Couple of measures you take: - open windows - multiple 4Ltr freezer blocks work well - stay at the pool till late - sleep on concrete or tiles - use fans - wet towels & buckets of water for feet are pretty good That and eat lots of icy poles (don't laugh) and drink water.
- nomoresecrets 17y ago
  I think anyone who reads HN who needs to be told to open windows in order to keep cool should maybe hand in their hacker badge.
  - bootload 17y ago
    "... I think anyone who reads HN who needs to be told to open windows in order to keep cool should maybe hand in their hacker badge. ..." It really depends. On the really hot days having a window open increases the interior temperature if the previous days have been cooler. On successively hot days leaving the window open decreases the interior temp but only if there is a wind. I don't know what latitude where you come from since you don't have any identifying information but being smart has nothing to do with understanding how to keep cool. It comes from local knowledge. If you come from the continental Europe or the UK I'd guarantee you'd miss half these hacks due to the heat.
cromulent 17y ago
When I lived in Melbourne and the house was over 30C, I would take a soaking wet towel and use it as a blanket on my bare skin. It sounds bad and the first minute is a bit creepy (until it warms up to your body temperature) but I would fall into a deep sleep in 10 minutes. It worked for me.
arithmetic 17y ago
Think of the winter that will be here very soon, and the time when you'll have to turn on the heater constantly. A few days of sun (especially in a city like Seattle where sighting the sun is a rare occurrence), is not that hard to deal with. Open out the windows, switch on the fan if you have one, take a cold shower and you'll fall asleep.
mleonhard 17y ago
Get a waterbed. Sleep on it with only a sheet between your body and the cold waterbed bladder. Keep the waterbed covered with a blanket during the day.
mhb 17y ago
If only Starbucks were open all night...
mr_luc 17y ago
No clothes + fan. No matter how hot, you'll start needing a sheet to keep the surface of your skin warm. It works for me in an AC-less shack on the equator!

50 points by 321abc 17y ago

Air conditioning is a wonderful thing. And, often, cheaper and more environmentally friendly than the things described here.

dmoho 17y ago
Here are most of the suggestions from the link: - Have fan with a pan of ice in front if it pointed towards you - Keep a damp hand towel on your forehead - Put an ice pack under your neck - make a rice sock, put it in the freezer and then inside of your pillow - sleep nude - sleep in a 'spread eagle' position - take a cool shower, wet your face, run your wrists under the cold tap Please correct me if I'm mistaken - How does an air conditioner use less energy than a fan turned on for the same amount of time? I did a quick search and most of the hits say that air conditioners use more power. (Here is one of the links that came up: http://www.todaysgreenconstruction.com/2008/07/battle-green-fan-vs-air-conditioner.html http://www.todaysgreenconstruction.com/2008/07/battle-green-...).
- calambrac 17y ago
  You had to expend the energy to freeze the water. You probably did that with a freezer, which runs using a compressor just like an air conditioner, except that it has to get a lot colder. I think you're still right that it comes out cheaper, though, because you'd be spending most of the freezer's energy output anyways.
  - jacquesm 17y ago
    The freezes compressor will run longer if you stuff it with things that are not yet at the temperature of the rest of the stuff in the freezer. This is also why it is a good idea to de-ice your freezer every now and then, keeping all that ice at a low temperature against the leakage through the walls of the freezer costs energy.
    - Elepsis 17y ago
      I'm not so sure this logic makes sense -- in fact I think it might be entirely backwards. I've always been under the impression that though you pay a penalty for freezing things the first time you put them in, thereafter a full refrigerator (and freezer) is actually much more efficient because it's more difficult to keep air cold than it is to keep any variety of items that are more dense. If we're talking about leakage, too, air obviously exits the freezer much more often than its contents do.
      - swombat 17y ago
        Air has a very low heat capacity. It doesn't take much energy to cool a cubic metre of air quickly (see air con, for example). On the other hand, cooling a cubic metre of water and other watery solids takes a load more energy. In terms of keeping it cool, that probably depends on how good your freezer's insulation is. If it's really good, it probably doesn't take too much energy to keep things cool (air or otherwise). If it's not so good, you'll incur a constant "your freezer sucks" tax. In the case being discussed, we're talking about freezing stuff every day, and letting it thaw in/near your bed during the night. So the cost would definitely be there.
        calambrac 17y ago
        No doubt there's still an additional cost, I just don't think it would be high enough to make it more expensive than running an air conditioner, given that you're going to be running the freezer regardless (depending, of course, on how much we're talking about. I'm picturing a window unit vs. a window fan with a baking pan's worth of ice). Any ideas on how to be more rigorous about thinking this through or running an experiment?
        swombat 17y ago
        You could take a certain quantity of ice, figure out how long it takes to melt under a fan in hot weather, then calculate the energy required to get that quantity of water into ice (heat capacity equations), and you'd have a rough figure for energy spent per unit time. Then compare that with the energy consumption of an air-con unit.
- phreanix 17y ago
  Let me get this straight, you're asking how an air conditioner uses less power than a regular fan? While I can't cite any wattage/amps/etc. figures, an air conditioner runs several things besides a fan motor, most notably its compressor. The more advanced ones also have other electrically driven parts, like a thermostat. As for real world stats, when I lived in the Philippines, I can say for a fact that running a fan vs an airconditioner makes at least a 60-70% difference in my electric bills.

mannicken 17y ago

When it was 40C+ here in Seattle a couple of weeks ago, I simply went outside and slept there in a nice cool 30C+ weather. If you have computers and electricity, by 10-11pm it will be significantly cooler outside so if you have a deck or roof or backyard, try sleeping there.

brianto2010 17y ago

Better idea... http://lifehacker.com/5335024/how-to-build-a-diy-dorm+legal-ac http://lifehacker.com/5335024/how-to-build-a-diy-dorm+legal-...

windsurfer 17y ago
I highly, highly doubt that would actually work. You would be much better off taking advantage of evaporating water somehow, such as putting a light damp cloth in front of a fan or something else. The problems with that design are highlighted in the comments, but it mostly comes from really not having enough surface area.
- brianto2010 17y ago
  Care to explain? I am not good at science/physics.

jrockway 17y ago

I think most of these suggestions just give you something to do while you make yourself sleepy.

edw519 17y ago

Many of these ideas are variations of an evaporative or swamp cooler. They work great west of the Rockies because of the lower humidity. They don't work very well at all east of the Rockies. Try a fan with some ice in August in Miami. You won't be hot. You'll be hot and wet. Better to just turn on your ac.

hooande 17y ago

Any YC founders who spent the summer in Boston know that this information is very valuable. Bookmark this one in case YC moves back out there and you have to borrow an air conditioner from Jessica.

bootload 17y ago

"... How to Sleep Comfortably on a Hot Night ..." hotest it got here in Melb last year was 46C and multiple days above 43C with extreme fire weather ~ http://www.flickr.com/photos/bootload/sets/72157614397725714/ http://www.flickr.com/photos/bootload/sets/72157614397725714... Couple of measures you take: - open windows - multiple 4Ltr freezer blocks work well - stay at the pool till late - sleep on concrete or tiles - use fans - wet towels & buckets of water for feet are pretty good That and eat lots of icy poles (don't laugh) and drink water.

nomoresecrets 17y ago
I think anyone who reads HN who needs to be told to open windows in order to keep cool should maybe hand in their hacker badge.
- bootload 17y ago
  "... I think anyone who reads HN who needs to be told to open windows in order to keep cool should maybe hand in their hacker badge. ..." It really depends. On the really hot days having a window open increases the interior temperature if the previous days have been cooler. On successively hot days leaving the window open decreases the interior temp but only if there is a wind. I don't know what latitude where you come from since you don't have any identifying information but being smart has nothing to do with understanding how to keep cool. It comes from local knowledge. If you come from the continental Europe or the UK I'd guarantee you'd miss half these hacks due to the heat.

cromulent 17y ago

When I lived in Melbourne and the house was over 30C, I would take a soaking wet towel and use it as a blanket on my bare skin. It sounds bad and the first minute is a bit creepy (until it warms up to your body temperature) but I would fall into a deep sleep in 10 minutes. It worked for me.

arithmetic 17y ago

Think of the winter that will be here very soon, and the time when you'll have to turn on the heater constantly. A few days of sun (especially in a city like Seattle where sighting the sun is a rare occurrence), is not that hard to deal with. Open out the windows, switch on the fan if you have one, take a cold shower and you'll fall asleep.

mleonhard 17y ago

Get a waterbed. Sleep on it with only a sheet between your body and the cold waterbed bladder. Keep the waterbed covered with a blanket during the day.

mhb 17y ago

If only Starbucks were open all night...

mr_luc 17y ago

No clothes + fan. No matter how hot, you'll start needing a sheet to keep the surface of your skin warm. It works for me in an AC-less shack on the equator!