A Do-It-Yourself Air Conditioner with Evaporative Cooling 5 Gallon Bucket

image42-300x225The people over at Gray Wolf Survival have this amazing little air conditioning project that is a perfect addition to any household that doesn’t have flowing air wafting through. It was created by [Figjam] for a trip to Burning Man, where all kinds of crazy ideas are bred in the hot dry heat of The Playa sun.

The design uses no ice, which is the cooling agent typical found in other DIY air conditioners. Those generally cut holes in the top of a cooler, put a fan on top to blow the air down across the ice. This is similar, but acts more like an evaporative cooler (not really a traditional air conditioner but it does the job).

397648283-300x225It uses a LOT less energy than an air conditioner unit so there won’t be a need to increase the power capabilities of a simple system to work it, and it can reduce the temperature by up to 30 degrees as well as alleviate the dryness associated with living through a Burn. It runs off 12V DC so it can either use the solar panel or connect to a battery. It has a 12V power plug for this, and draws as little power as absolutely possible. Plus, it has the ability to easily connect to a larger water source so it won’t have to be continually refilled. These considerations make it very portable and perhaps backpackable as well.

[Figjam] took a 5 gallon bucket, wrapped the inside with two layers of swamp cooler matting, made a loop of hose above it connected to a submersible pump and ran a fan out the top with piping. Connecting it to a shelter is done with a vent hose.


  1. the gambler says:

    so a mini swamp cooler. nice compact design but if you are doing this please remember that these coolers even though they do work well are just magnets for mold.

    • T says:

      And magnets for a lot of other stuff you don’t want: http://en.wikipedia.org/wiki/Evaporative_cooler#Disadvantages

    • lel says:

      It seems like the push for hackaday to poop out more content more regularly has really had a negative effect on the quality of what’s being found to be a worthwhile post. This is a mostly copy and paste article of something that’s already been on hackaday before.

      The writing is terrible and the content is mediocre at best. “Perhaps backpackable as well”???? I guess you must have a big backpack bro.

      • inhenhe says:

        I don’t want to say it, but I do agree. The writing is very poor in this particular article and again in the one on making lockpicks. Various mistakes and subject matter ignorance that can be corrected simply by googling is quite prevalent. It is rather surprising considering each post is just a hand full of sentences. When dedicated college students can bang out a 3000 word paper hours before it is due and still get reasonable grades then why can’t professional writers make flawless 300 word posts?

        • inhenhe says:

          I appreciate my critical post not being blocked or deleted by the way. It is just so frustrating to see people getting paid to write and not be superior to people writing for free.

        • Job says:

          Read almost every post on the first page right now and you will find mistakes that could have easily been corrected. I find it difficult to believe that paid writers don’t have 30 seconds to proof-read a story.

        • eas says:

          I don’t think you understand writing very well.

          First, 3,000 word papers banged out by undergrads in a the hours before it is due aren’t particularly nice reads, and if the paper does actually get a decent grade, then they probably spent a good bit more time learning about the subject in class, and in their reading.

          Second, writing good short pieces is generally considered harder than longer pieces. Mark Twain once apologized to a correspondent by writing, “I didn’t have time to write a short letter, so I wrote a long one instead.”

          Don’t get me wrong, I’ve been rubbed the wrong way by plenty of posts. As a reader, I think I’d prefer fewer higher quality posts. Of course, I’m not paying for this, I’m not sure I’ve ever even clicked on an ad here. So the incentives for better quality aren’t really in place. Instead its the race-to-the bottom that so many advertiser-funded sites seem to be locked in.

      • Greenaum says:

        Has the amount of content gone up then? I thought it seemed to. When you look at a post, after a day or so it’s disappeared a few pages back.

        Yep also standards seem to have fallen a bit. I remember we had a dude who made his own ski-lift, and all sorts of impressive stuff a few years ago. Recently we’ve seen stuff like “man connects Arduino to lights”, and then it turns out it didn’t matter that it used a whole devkit, cos he was scrapping the whole thing the next day anyway.

        Not all articles are that bad, though the one I mention (more or less) was only a week or so ago.

    • Anon says:

      You can use ceramics and then chuck it in the fire every evening, all the organics stuck in the ceramic element will eventually turn into Carbon and CO2.

  2. MS3FGX says:

    So besides being largely a copy & paste job, this post doesn’t even link to the correct source. Gray Wolf Survival is just talking about the cooler FIGJAM did, which is here:


  3. garym53 says:

    Useless in a humid environment…

    • medix says:

      No, actually these work quite well in humid environments. They’re in use all over Delhi, Agra, etc.. and do a pretty good job even during monsoon season. Maybe not as efficient as real ‘AC’ but it was definitely better than nothing at all..

      • garym53 says:

        Sorry, not true, these units rely on evaporation which is severely curtailed in a humid environment – I have experienced them before in humid Sydney, all they do in a humid environment is work as a fan *and* make the atmosphere even more humid thereby lessening the ability of the body to cool itself via sweat. of course a fan is better than nothing at all, but you would be better off with just a fan.

        • medix says:

          Meh.. go to Agra and lemme know how that works out when it’s the only option available.

          I never said it was efficient..

          • Sven says:

            They may work somewhat in humid conditions, but saying that they work “quite well” is not true.
            The fact that it’s the only option in some poor areas doesn’t make them work any better either.

          • garym53 says:

            I wouldn’t go there to save my life, but you can’t go above 100% humidity and once you go there this unit is zero efficient (in fact less than that because the motor pumps out heat) – and I doubt it gets hotter there than in the west of Sydney (> 45C).

          • Chad says:

            To all of you who claim that these are working well in humid environments, please supply data. Without a clear definition of what “works well” means and some sort of measurements to back it up, you really don’t have any authority with which to speak. Anecdotal comments are of very little value. If you don’t understand the basics of psychometrics, this is probably all magic to you.

          • medix says:

            Holy crap, chill out. I wanted to point out that, yes, these DO work, though *results may vary. I am well aware that environments with high humidity will render these things useless. Since no one else has provided any factual data on efficiency, then an experience based ‘recommendation’ will have to do.

          • fartface says:

            They do not work at all in humid environments. 100% humidity can not be increased, and once you are above 80% humidity, it feels worse adding more humidity.

            Yes I know this as a fact, where I live it’s 85% now and considered low humidity today. A home depot bucket cant violate physics.

          • inhenhe says:

            You could have just accepted that what you said was wrong. Just have some humility and learn from others. You posted that they work in humid environments, citing one of the most extreme environments, then contradict yourself later.

            “No, actually these work quite well in humid environments. They’re in use all over Delhi, Agra, etc.. and do a pretty good job even during monsoon season.”
            and later
            “I am well aware that environments with high humidity will render these things useless.”
            apparently not

            Swamp coolers can only cool if the dewpoint is lower than ambient temperature and then whatever that point is becomes their maximum of cooling ability.

            For me today that would mean it could, if it was big enough, change the temperature in a small space from 87 degrees to 84 degrees. Not useful. In arid climates they are fine, elsewhere not so much.

      • m1ndtr1p says:

        No, they’re quite useless in humid environments… Summers here on the East Coast of Canada generally mean 95%+ humidity most of the time, I’ve built several swamp coolers before, and other than circulating the air around you, they make absolutely no difference, you’re better off with a regular fan if you don’t have access to an AC unit…

    • Justin says:

      One could replace the water with methyl alcohol to provide cooling. There would be issues with air alcohol saturation and of course it would cost a lot more to operate.

    • macegr says:

      Which is absolutely a non-issue on the playa, where the humidity might not rise above 20% during the summer. Right now it’s 17% and get sub-10%.

      • garym53 says:

        Yes they work fine in dry conditions like,for instance, the Australian outback where you will often see one dangling on the front of 4 wheel drive, alas, 90% of the population of Australia live along the humid coastal areas. I had one for years and if the humidity dropped to about 60% I would put some water into it -otherwise I just used it as a fan. I know from experience they not only do not work in humid conditions but can actually make the situation worse – the best evaporative cooler under those circumstances is built into your skin (obviously some people have better systems than others – you know who they are they always have those dark areas on their shirts just around the arm pit). I was just pointing out what I see as a significant limitation of these systems, Give me something that can pull a vacuum any day.

  4. Sven says:

    Wouldn’t it be possible to build an evaporative cooler with a heat exchanger so the moist air is circulated outside and dryer inside air is circulated indoors?

    • garym53 says:

      One would think so I but I am not aware of any evaporative cooler that wasn’t a “spot” cooler – I would assume from that that their efficacy, in general, is so low that any kind of secondary transfer is non-viable.

    • Thinkerer says:

      I’ve wondered this myself, and from what I can tell by the time you build the heat exchanger, dual fans etc. etc. for the modest amount of cooling that is possible the cost gets close to a compressor-driven A/C unit that will be a lot more effective and doesn’t have to be refilled and cleaned all the time. Add to this that cheap A/C units from China are very affordable and car A/C units are now well integrated (they used to be terrible add-ons that would cause the car engine to overheat much of the time) and this seems like a very limited market. I also have a hunch that people who use these in very dry climates like the humidity increase too, but I could be wrong.

      • Sven says:

        That’s pretty much what i figured… That a compressor cooler would be close to the same efficiency as a heat exchanger i mean, otherways we would have seen thousands of these things for at least pre-cooling in hot dry environments.

    • Thinkerer says:

      Addendum: We’re talking small units here – large scale evaporative cooling is everywhere; on top of large buildings and in large industrial plants and in power generation, but these are cooling the water that is then run through another exchanger to pick up heat from a process or the building A/C condenser or the post-turbine side of the power plant.

    • Maxzillian says:

      Yes, I believe they’re referred to as indirect evaporative coolers. I’ve also tried dabbling with a benchtop setup that uses calcium chloride solution to draw moisture from the air before the evaporative cooler to improve performance, but it was only good for reducing humidity by less than 5% (in a 40% environment) and also heated the air a few degrees in the process.

      Calcium chloride has a great affinity for moisture, but once you put it in solution to make it easier to handle/process, it only works down to around 20-30% humidity.

  5. Lars Haulin says:

    For those wondering: The article uses Fahrenheit, and a temperature difference of 30 degrees Fahrenheit is a difference of 17 degrees Celsius/Kelvin.

  6. T says:

    Could you blow the cold output air against a (glass) plate so the warm input air condensates against it reusing the water? Or does condensation create too much heat?

  7. Craig says:

    Uggh… “It uses a LOT less energy than an air conditioner unit…” It doesn’t If you include the energy required to make the ice. You might save if you’re just trying to cool a room instead of a whole house, but that’s not fair comparison. I saw this “new” invention all over the media a month or two ago. You’d think the air conditioner people were suppressing the technology.

  8. Interstellar555 says:

    Can anyone recommend an alternative for the swamp cooler pads/matting? I was planning on building a small swamp cooler during the last heatwave in the UK but cooler matting (straw or synthetic) seems to be incredibly hard to come by over here.

    I tried using some old cotton material, which worked reasonably well, Just wondering if someone might have found something better.

  9. Jorj Bauer says:

    If you use a wicking filter (as commonly used in humidifiers), then you don’t need the pump.

    Source: that’s what I did at Burning Man. Still needed electricity for the fan, of course.

  10. James says:

    When i was 14 or so the A/C broke and there was no money to fix it until the next year. I got so sick of the heat I built a swamp cooler for my room. It was a 10 gallon fish tank with about 2 in. of water in the bottom. I attached a clip on fan to one wall of the fish tank and hung a couple of paper towels over a stick in the middle so the ends hung in the water. It cut the edge off the heat. Now i just live where it doesn’t get hot so I don’t have to worry about such things.

  11. Josh says:

    HOW THIS WORKS: Wiki tl;dr
    Water absorbs energy changing from liquid to vapor. The cooling results from the energy absorbed by the water when it is forcefully evaporated. Therefore, forcefully condensing the high humidity air after it exits will *release* energy back into the air at the same rate. There is no trick with which you can keep the cool air, and loose the humidity.
    This is a constant enthalpy process that moves the energy from sensible (temperature) heat to latent heat (essentially humidity). Temperature change is directly related to humidity change on the psychrometric chart.

  12. DaveO says:

    I live in Brisbane Australia – hot and humid in the summer. We had a portable evaporative cooler and I can confirm it was almost completely useless. It felt slightly cooler immediately in front of it but a fan was better. I suspect that it raised the humidity in the room so in high humidity could actually make you feel warmer.

  13. Rusty says:

    Cool idea when you are in a pinch and it’s top of the season for AC Repair Services. It’s an quick inexpensive solution.

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