Spencer’s Homemade Air Conditioner

Spencer from Ohio made this incredible build using some good old american muscle. This closed circuit version of the homemade air conditioner uses a radiator for efficient heat transfer, and looks awesome in the process.


A spare radiator from a 1976 Triumph Spitfire ensures great heat transfer between the water and the air. A wooden frame supports the radiator and attached fans.


Not just one, but two fans circulate air through the radiator and the room.


Two water fountain pumps are used to circulate the water between the cooler and the radiator.


Here we can see the warm water returning to the cooler. How does the whole thing perform? In Spencer’s words, very well.

Homemade Air Conditioning Plans and Pictures
Original Design
Geoff’s Homemade Air Conditioner
Heat Exchanger Improvements
Water Supply Improvements
Technical Notes
Other Designs
Pete’s Homemade Air Conditioner
Anonymous’ Homemade Air Conditioner
Spencer’s Homemade Air Conditioner
Final Design
The Black Beauty

27 thoughts on “Spencer’s Homemade Air Conditioner

  1. Dear Sir .We are lucky to get your design about ice airconditioner in the web,because we are going to use yr idea for our seaside camping site in Galang island, a small island near Singapore but don’t hv electricity. We hope yr idea will be very useful, because
    our island is hot, but the the scenery is very beautiful,Thank You

    Sincerely Yours

    Arianti from small Island Indonesia

  2. Hi.
    I don’t sure i understand.
    Is there anything that makes the water cold? or that is a thing i should care of by putting ice in it?


    Yoni, from Jerusalem

    • Hi Yoni – the water should be cold (or else it isn’t going to cool much), but how you cool it it up to you. Using ice or a cold water feed appear to be the two primary choices.

  3. I was wondering about this….

    If a old fridge or freezer can be found / salvaged, do you think it would be possible to utilise the cooler on these to run a DIY air con?

    I was thinking if a small fridge can be burthcered a fan could be incorporated into the frame and the door removed.

    Any thoughts on this? 😀

    • It’s possible, but if done in the manner you describe, would actually lead to the room heating up due to inefficiencies of the fridge!

      A fridge does not magically make cold, it pumps heat away from it’s interior insulated chamber – so the heat must go somewhere. That’s why the back of your fridge is always nice and toasty.

      You could possibly modify it heavily so that the heat could be pumped outside via a window (like an air conditioner) but unless you’re familiar with working with pressurized gases it will likely be rather dangerous.

      • I think the idea of using the back grille off a fridge is brilliant. It’s already a frame of thin tubes, engineered (well..) for heat transfer. You may have to rinse out whatever poison was running through it originally, but set that thing up with a couple of box fans and you’re good..

  4. Sir,

    Is there anything that can be used insted of water. If we fill co
    per tube with Nitrogen Gas or any other gas which tubes cold permently.
    pls advice.


    • Hi indika – Running a loop of liquid nitrogen might be possible but would be rather impractical in my opinion. Pumping will be near impossible with retail parts, and the liquid nitrogen will quickly boil off unless you create some sort of pressurized loop – at which point you’ve almost made a real air conditioner!

      You might be able to pour a small amount into a gravity fed tube that the fan then blows over, but it would be more of a “one shot deal” if you will and more useful for a demo rather than practical use.

  5. dear, me impressed ur invitation . is it possible cool air through radiator with icy water in thermocol box please reply me ! matter is very urgent because kolkata ( india ) is very fucking hot dear .
    with regards partho

  6. I am building this system, can any give me a idea that if we manage to pump the liquid water at a higher rate say 5 lts per minute, will it change the cooling.

    regards, Jeetu

    • Hi Jeetu – Flow rate is not a significant contributor to the cooling rate of the system above a certain low threshold. It is better to focus your energy on the efficiency of the heat exchanger itself.

  7. Hi Geoff, thanks for your reply, you mean to say the larger and better quality the radiator and fans, it would contribute to the efficency of the system.

    Thanks once again. Jeetu

  8. Hi Geoff, I am an engineering student. I want to make project of home made air conditioner, i need some more knowledge about it & suggest me some more idea for project

    • Hi Aman,

      First I’d suggest reviewing the concept of a heat exchanger and then identify how this homemade air conditioner could be classified as a heat exchanger. If you’re looking to build one yourself, I’d suggest working off the Black Beauty design, as a radiator will drastically increase performance. I would not recommened the copper coil approach as copper has become just as expensive as a true radiator in the past years, and does not perform nearly as well.

  9. Hi Geoff,
    I am glad you are still replying to these threads. I am currently building my system and I am using a water fountain pump like the guy who made this design. However I am having trouble creating an air tight seal between the vinyl tube and the pump. How did the guy Spencer create an air tight seal as I cannot seem to find the correct adapter between my water pump and this. The only two problems I can thing of are:
    1. The pump cannot handle the pressure of pumping water through 30 feet of tubes.
    2. I am unable to form an air tight seal between the pump and the tube.
    Any advice would be helpful as it is quite hot this summer.

    • Hi George,

      First, check for any leaks by rubbing dish soap around your seals – poor seals will bubble up. Secondly, it seems to be that your pump may be undersized. There is no way around this other than reducing tubing length or (more realistically) buying a more powerful pump rated for a higher flowrate for a given resistance.

  10. Why doesn’t anybody,including here,use one of those thermo-electric coolers? They’re cheap,cheap to run,& you wouldn’t need to keep refilling with cold items or water and ice. Its those coolers that plug into cigarette lighters or you can plug into home outlet.They look identical to a non-electric cooler.I’m going to have to make one to show what I mean maybe.Radiators a great idea,but I was thinking of a heater core from a car, which pretty much is a mini radiator,it would make a nice desktop one.Get one of those thermo-electric coolers that hold a 6 pack exactly,use heater core,& you have a relatively small unit that doesn’t need to be “recharged” for lack of a better word!

  11. Dale,

    The problem you would run into with the thermo-electric coolers is the exact same you run into by placing a freezer / colder refrigerator in the room. In order to cool the inside of the cooler, the heat must be transfered somewhere (same principle as a regular freezer). The cooler simply moves the heat to the surroundings, thus, the freezer would be heating up your room at the same time the water is cooling your room. Thus, you would end up heating up the space because, since 100% machine efficiency is impossible, there would be more heat production when the heat from the cooler, fan, and pump were combined as opposed to heat absorbed by the water.

    A very good idea, but remember, the heat must go somewhere, which leads to either running the water our of the room or manually emptying the water, thus completely removing the absorbed heat.

  12. Ok, nice designs guys, but i need to ask a question…is this really more efficient than just buying an air con for less than a $150 from the store? It really depends on the cost of electricity.
    If you need to freeze water to make ice, it takes energy, your fridge or freezer. you use this frozen water to cool the basin or tub of water that you then cycle. over time the water warms, the ice melts and your project has eventually be come the same temp as the air, which is now becoming hotter again. Also, the fan you have used is using electricity, as is the water pump you are using. Your electricity costs between these 3 devices I can imagine is now using more than a small 3000-5000 btu air con. In the end…are you really saving anything? I dont think so.
    Use wind power and geo thermal cooling, no electricity needed.
    The ground water is always cooler than the air, if you are using it in a hot climate. You dig a small well, make a sealed circuit that has a finned or coiled exchanger at the bottom of the well and then another exchanger at the top around/close to your “cooling fan” similar to the coiled tubing around the fan.
    To turn both the fan, to force air through the cooling coils, and circulate the water from the bottom of the well to the cooling fan height…use a small wind turbine. Using the wind, and the mechanical power using a pulley or gear driven pump for the water…you know have a self contained, self circulating unit. As long as there is wind, and water in the closed loop system, you will have continuous cooling. If you have access to electricity that is fairly cheap, you can also then use a motor to circulate the water,coolant, and run your fan. At this point you can also use a glycol, be sure you dont spill and contaminate the ground water, and it will increase your cooling capacity and decrease corrosion in the system if it was just plain water.
    My full scale version will be prototyped in Brazil, where electricity is expensive! And where the air is never less than 22C at night and during the mid day it can be 35C in the shade. The ground water below 5 Meters used for cooling is 15C or less.
    I will take pictures along the way.
    Good luck with your project.

  13. What pump would you recommend for me? (and a link if possible)
    -1/2″ inner diameter vinyl tubes
    -5 ft of vinyl tubing and 20 ft of copper
    Thank you for posting these ac units!

  14. Ok, I took this design a couple steps further. Same radiator set up as pictured. Only i am using a chest freezer in my basement. I put the water anti freeze mix in a rubber made storage container, place the container in my chest freezer. The water is around 20 degrees. The radiator was placed in my forced air duct work. I turn my thermastat on fan only manual setting. Air is passed threw the cold radiator inside the duct work. This cools my house very well. The heat from the freezer is in the basement, which is much cooler anyways. Its kinda like redneck central air, lol.

  15. My parts list includes: $16 for a 132 gph aquarium pump (ebay), $10 for 25 ft. coil of 1/2 soft copper from the local metal recycler, an old industrial box fan (600 rpm), and $2.50 for 1/2″ vinyl tubing from Home Depot. 45 minutes later, I have probably the ugliest swamp cooler ever built, but it helps cool an uninsulated garage in Georgia in 100 degree heat. The radiator was my first choice, but the one I had from a Honda is pretty much scrap itself – too many leaks! Thanks to all you guys for your help.

  16. Has anyone tried adding rock salt to the ice?
    I use a brine solution when I cast net large gizzard shad for catfish bait I fill Ice chest maybe 1/3 with ice, add maybe 1 cup of rock salt. The shad will freeze while in the cooler. Rock salt drastically drops the temp of ice. I’ve also used rock salt in cooler when camping. I found that I had to keep cooler well stocked or items such as milk would freeze!!
    Any feedback about adding rock salt from an engineer or student will be appreciated

  17. WoaH! There’s comments on this page now! Really really cool this site is still up!
    @ George, if you haven’t fixed your leak problem I used just regular hose clamps, the type that uses a screw to tighten and are found in cars n stuff. Just don’t go to crazy tight or you’ll break stuff. (its been like 2 years so i hope you figure something out)

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