Introduction: Homemade Air Conditioner

Picture of Homemade Air Conditioner

Before I get started, I have to give props to Geoff Milburn, at whose plan it was I copied. I'm not smart enough to think up something like this on my own. That being said, one of the places I work has no AC, but I'm allowed to have fans, so this seemed like a good project for me. It's not perfect yet, but it does cool the air better than just a fan.

Step 1: Attach Copper Tubing to the Fan

Picture of Attach Copper Tubing to the Fan

I took the grate off of my fan, so I could put the heat exchanger on the inside, hopefully making it look better. I'm using copper tubing as the heat exchanger, although you could use something else, as copper is not cheap, and not easy to work with. As you can see in the second photo, it's very easy to kink the tubing, in which case, you stop the flow of water. I grabbed a hole saw to use as a die to wrap the tubing around, and the teeth held nicely against the grate of the fan. As I was going along, I used zip ties to hold the tubing to the grate. Of course, because this will be inside the fan, make sure to clip off the loose ends. Also, make sure that you have both ends of the copper tubing sticking out of the fan, so you can hook up the tubes to the pump.

Step 2: Attaching the Tubing to the Pump

Picture of Attaching the Tubing to the Pump

Now, the cheapie pump I bought would only fit 1/2" ID tubing, and they didn't have anything that would downsize it to 1/4" for me, so I just rigged it up. As you can see in the first and second photos, 1/4" tubing fits quite nicely around the copper tubing. In the third photo, you can see how I just inserted the 1/4" into 3/8", into 1/2" tubing, which would then fit onto the pump. This of course leaked, which necessitated the use of hose clamps, photo 4. I feel that this greatly reduces the effeciency of my pump, but now I have a reason to buy a bigger, stronger, more manly pump! Either that, or buy bigger copper tubing, which is not as exciting.

Step 3: Submerging the Pump and Testing It Out

Picture of Submerging the Pump and Testing It Out

I bought a foam cooler to hold my coolant(ice water), as I have easy (free) access to both water and ice. Once I had it all hooked up, with one tube going from the pump into the heat exchanger, and another from the heat exchanger back to the cooler, I submerged the pump and plugged it in. At this point you'll be able to tell whether or not you have leaks real quick. If you do, just shut it off and tighten things up. If you've got a hole in your copper tubing from over-zealous bending, you might have a tricky problem to solve. I didn't have that problem, so I couldn't begin to tell you how to solve it. (I am partial to JB Weld for all things broken though) I've noticed that towards the end of the copper tubing, I'm not getting any condensation, which means by the end, the water has lost it's cooling effect. When I get a bigger pump, the water will flow much faster, and hopefully won't warm up as much. Well, that's about it, any suggestions would be welcome!


drakonscaleon (author)2016-07-09

You can't just throw tubing in there like that and call it a day. It's not efficient, and does about as much cold air as a seltzer bottle. You have to wind it in a coil for the coolant to actually have any effect, whatsoever.

smokefire0 (author)2016-06-24

a nifty modification qould be to use 2 coolers one inside the other with water in the smaller one surrounded by dry ice in the larger one it would super cool the water with less waste and if you wanted to get fancy wrap some of the copper tubeing around the smaller cooling to have direct contact with the dry ice causeing a greater surface area for cooling. also add alil salt to lower the waters cooling temp

BarbaraG76 (author)2016-06-05

What a cool article ha get it? Cool! Seriously am gonna make this! Not looking forward the the $$ copper tubing but the rest is great!

untar1 (author)2016-06-01

Could someone provide any efficiency specs(what temperature can this cooler maintain)?

billw129 (author)2012-06-29

I have the solution to all of the rust and saltwater problems. Just get a pump that does not need to be submerged. Get one that has an intake and output nipple on it for hooking up to tubing then run from your output to a plastic tube that goes to the coil of copper then from the copper output put a plastic tube that goes in to the cooler and forms another coil. then back in to your pump. Fill the system with antifreeze. Now your copper tubing is isolated from the salt water and you actually get some rust prevention from the anti freeze. Oh and BTW fill the cooler with ice, rock salt, and salt water this will super cool it. It will probably form Ice on the coil rather then condensation.

CraigR12 (author)billw1292015-07-23

Great idea, plus removing the submersible pump will help prevent the water from warming up from the pump running. The pump generates heat too and will cause the water to warm up faster!

shaidyn made it! (author)2015-07-03

I just finished making this and it's working like a charm. I don't have ice water in it yet, just cold water, and it's already blowing nice cool air. I love the instructions, but the list of parts is a bit slim, so I'll add what I used:

20 inch box fan.
A 1/6 horse power submersible utility pump.

20ft 3/4" copper tubing.

A 40 quart styrofoam ice cooler.

A washing machine connector hose.

2 hose clamps.

a whole lot of zap straps.

Tools required were:
A glue gun (probably not necessary, but I glued the ends of the washing machine hose to the ends of the copper tube before applying the hose clamps).

Clippers to cut the ends off the zap straps.

A knife for cutting holes into the ice cooler (I cut holes on the top to feed the hoses into, so I can keep the water colder for longer).


Rotating pipe cutter (to cut the copper tube to size; I used about 190 feet).

Total money spent: $175, but the fan and pump are very useful on their own.

Total time spent: About 90 minutes for construction.

NiqN (author)2015-07-01

Isn't it better to use an old car radiator instead with the in built fan rotating towards you?

pictsidhe. (author)2015-05-28

For the people wanting to cool their cars.

Make sure you have a white car, they don't get half as hot! A paint job is probably worthwhile if you are a PI and don't want to trade your car. Instead of colling your car, freeze some ice cushions to sit on, A few layers of fleece or a folded towel and it can be adjusted for the cooling you need.

arpit.bhatnagar.7 (author)2015-02-19

I made a homemade AC using 20 W motor,ice box,copper windings and all other but the effect is not coming as i expected ,i.e,the cooling effect is not MUCH as we expected from so much hard work...

PLEASE help me out of this (to increase the cooling effect) .

I covered the ice box with aluminium foil.

NalinK (author)arpit.bhatnagar.72015-05-07

Your work looks neat man. Here are some points...You should add coils behind the fan as well and increase the flow of water by installing a better pump. Insulating the pipes between the ice box and the fan can prevent the temperature to increase while in transfer. Also, try to shorten the distance as far as possible. Keep the fan speed low, so that the air may have sufficient time to stay in contact with the coil and become cool in the process.


PIman (author)2007-06-11

I am a PI and want to make a rig to cool my van(130 F). I need suggestions (& spelling tips).

STC here: You want to cool a van, huh... OK, do this -- Get a car or truck heater core from a junk yard, any kind.. Now get a bilge pump (pump for draining water out of a boat). Ice chest & hose to fit. Put the pump in ice chest with hose connected to out put of pump. Run hose to heater core & output of heater core back to ice chest. Now connect a small fan in front of heater core so the fan is pulling air through the heater core, not pushing it. As you know: You can do more work with a vacuum than with pressure. Place crushed ice in chest with one gallon of water. Now as the fan & pump are 12 volt just fix a plug so they can be plugged into the lighter socket. WALA COLD AIR................ If you put the heater core & the fan in a small box it will work much better. I used this setup some time back in my little motorhome when we were camping in the boonies. Had us looking for the covers... Nother though, If you had a solar panel that put out enough current, you could run this thing all day from it and keep that van cool all day, just add some ice as required. will work to keep a tent cool too.. many uses. STC we gone

hey hae u done this project ????
and if yes then does it cools as ac or not

hshah-1 (author)Swapnil242khadke2011-03-12

yes it cools the as a ac i have tried atleast makes 5-10 degree difference

hey can u plz tel me exctly how u made it...because i made and it is not giving much temperature difference from the fan

divyang6478 (author)hshah-12012-05-15

I am living in India and here there is so much hot climate, i have made so much thing from instructables Please tell me what, if i use a radiator of car and fan and make the same as above shown, so it will work or not?? your reply is important for me.

PhilS. (author)divyang64782015-02-03

If you can supply enough cold water, why not.....

PhilS. (author)Swapnil242khadke2015-02-03

I just said I did it in a motor home. And yep it cooled like a a/c unit. Had us looking for covers before morning...

brianroesch (author)PIman2007-07-25

I'm interested in cooling down my car too for Private Investigating. I'll just perhaps get a portable a/c unit and small gas powered generator. (silent generator).

PIman (author)brianroesch2007-07-26

How would you not die from the fumes? My small fan makes a loud noise. I have rigged s cooler with a fan that blows in?downward from the top an fore air over ice blocks and then out vent. Melts in the hot van, but i works for a short time. Any info on ac units would be great.

brianroesch (author)PIman2007-07-26

Pop the trunk a little and drag an extension cord around to the inside through the window into you a/c unit. Swamp coolers are cheaper than the a/c units. If you have a van you can mount the generator to the roof and cover it with a plastic box to protect it from the rain. The charging power pack inverters are not good because the watts are not enough. Gas powered generators are the best.

PIman (author)brianroesch2007-07-27

Swamp coolers work well in dry areas mine is humid(very). In the PI biz the box on the roof would be noted and then expose me. I like the concept though. Where are you a PI?

brianroesch (author)PIman2007-07-27

I'm not a PI yet----just training to be one down in Broward county Florida. Still deciding due to wear-and-tare on the car. I may just stick with my night job.
I'm currently working as an intern to get my CC license and in about two years my C and hopefully go on to my Agency license if all goes well. It's fun work, but very HOT!

bo88y (author)brianroesch2010-07-26

Until you find your more permanent cooling solution, it can help to keep a plastic jug of water in the car to sprinkle generously on the roof when it gets heated up by the sun. First you'll get some evaporative cooling, and then some conductive cooling. When the roof's too hot to touch, even water that's warm (from sitting in the car) can take a lot of the heat out of the metal in the roof and keep it from radiating into the interior. When my AC broke, I'd do this before opening all the windows, and it would make the car much cooler to get into on hot days. If you're sitting on hot days, it may well be worth it to close up your windows to wet down the roof once in a while.

brianroesch (author)PIman2007-07-28

A CC license is an intern license. Anyway, I hope you find a device to help cool you off. Running the car while parked all day is not good, especially when the companies only reimburse milage. A friend of mine suggested cutting three holes in the top of a large cooler filled with ice. Next, place three battery charged fans (one in each cut-out). One fan blowing down into the cooler and two blowing up.

maxpower49 (author)brianroesch2007-07-26

i'm working on a mini air conditioner that uses a 12 volt boat pump, a mini fan, and a inverter for cars and stuff.

PIman (author)maxpower492007-07-27

Let us know how it works out.

maxpower49 (author)PIman2007-07-27

i'll post it soon

eskimojo (author)PIman2010-07-10

(part 2) So we wanted to tap into that potential for quick cooling while mobile and compact(ish). Luckily professional sports already did the foot work. They made a jersey that has tubing attached to it and then the tubing has cooled water run through it. This was our jerry-rigged version plan. 1 Jersey(of no sentimental value) as much clear tubing as needed(the kind you can get at a pet store) a cheapo electric-water pump(12v) or fuel pump(we work at an auto parts store). some wiring + accoutrements. small 12v battery water(as use would be limited) Cold source(ice packs, ice blocks/cubes, frozen water bottles) a water-tight container. sew the tubing to the jersey, concentrate on the upper back, shoulder, neck area, in zig-zag pattern, coil tubing around cold source, clamp all connections, attach pump to power source and you have yourself a quick and dirty cooling jersey! you can wear it and it will bring your core body temperature down.

eskimojo (author)PIman2010-07-10

Why try and cool the whole van when you can just gool personell(sp?)? My friend is fabricating a Big Daddy suit(from Bioshock 2) and we have heard horror stories about the heat generated in large suits so we had a brain storming session. Basically your blood along with being the life-essense in your body(providing nutrients and sugar to your body's components and removing toxins, exchanging oxygen/CO2, etc) is essentially the cooling/warming system of your body.

PhilS. (author)2015-02-03

I made one something like this several years ago for cooling our motor home. we were dry camping, i/e no 120v power, 12v only... Used a boat bilge pump, tubing, heater core from a car heater, 48qt. cooler, 4 x20lb bags ice, started with one gal. water, 12v dash type fan. made a cardboard box for heater core and fan ,let fan pull air through heater core as you get better air flow, you can pull air better than pushing it. Had 34 deg. air out. Was hunting for more cover before morning, dang it was cold in there.. If your car/truck a/c goes out, look what you can do now, make your own... lol & yep == hot water works to....

Happy Trails


NickInventor37 (author)2015-01-27

If I pump hot water in, will it heat a small room?

Mason Wright (author)2014-07-26

Try adding salt to the ice/water combo it should make the water drop to 32 degrees

John Culbertson made it! (author)2014-05-15

Just assembled one of these, and it works great. Here is my list of materials used:

-120 GPH Fountain pump

-2 gallon water cooler from Lowes

-Honeywell 8" Fan

-1/4" OD copper pipe

-1/4" ID Vinyl tubing

Favorite part about this project is how fast it goes together I first read this post about 4 hours ago and now I am sitting at my desk with nice cool air blowing on me.

Great instrucable, thanks for posting.

Alamarus (author)John Culbertson2014-06-02

Hey I am trying the same thing you have but I am not getting very positive results:

130 GPH Fountain Pump

22Qt. Styrofoam Cool from Wal-mart

12" Honeywell Fan

1/4" OD copper pipe (10 ft.) I plan to get more tomorrow (details why below)

1/4" ID Plastic tubing.

I have put everything from Ice to frozen water bottles to frozen cooler packs and only once have I seen condensation on the copper tubbing. It was originally in a 5 gallon Homedepot bucket but the ice seem to melt and the temperature rose very fast so I switched it to the Styrofoam cooler.

I am thinking of adding more copper tubing to the back as some people on here have done so it will allow the air to suck in cold but I am not sure if this will help. Any advise is appreciated. I live in Colorado and live right next to the furnace with alot of electronics in my room. It gets very warm in here.

Any advise is appreciated.

John Culbertson (author)Alamarus2014-06-02

Adding additional copper tubing will make the biggest difference, and you also really need to load down the ice bath; I use a combination of water, ice cubes and frozen water bottles and try to completely fill my little 2 gallon cooler with as much ice as possible.

I have used this more since my post above and realized with a devise like this you really need to manage expectations, this will not appreciably cool down even a small room with this. I have mainly used it blasting right at my face while I was working at my desk and positioned by an open window aiming at my bed before I go to sleep when it gets over 100F, for these applications it works pretty well for about an hour or two with my little 2 gallon cooler.

Hope this helps.

Alamarus (author)John Culbertson2014-06-03

Well I added 20 ft. (30ft. total) more copper tubbing to it. around the front and the rest around the back. I have also put a trashbag in the cooler to keep from leaks. Unfortunately after all that, there is still no difference my room gets very warm regardless unless I have the window open (which has no screen and bugs are getting in all the time which is undesirable) and the door is open but there is no privacy.

I am left very disappointed because this idea DOES work for others so why not for me? what am I doing wrong? I would be pleased if this even cooled the room two degrees but nothing.

I am wondering if these ideas will help.

1. Decrease the amount of water in the cooler.

The cooler is a 22 Qt. Cooler that is halfway filled. more than enough to submerge the 130GPH pump. If I dropped the water level to just submerged level (with or without cold packs or ice) would that mean that since there is less water to cool it will stay cooler longer as there is less to cool?

2. Increase the fan size.

this is a 12" Honeywell but alot of people I see are using much bigger box fans. Would this increase airflow around the room and cooling it? My understanding is that in a closed environment like I am making is to cycle to air through the fan that will cool the air and cool the room.

3. Build a intake and outake for the air on the fan

The way I figure it is that if I build a intake around the back of the fan it will direct the air directly through the back coils where the water intake is at its coolest. And a outake to help control the fans direction. maybe funnel it down so the fans air is more centralized and condensed?

4. Use Saltwater Filled water Bottles. Use Salt Water

Since I drink alot of bottled waters I am wondering if refilling them with Water with salt will keep the cooler colder longer. I never took chemistry but my undestanding is that salt lowers waters freezing point and therefore will keep a cold source longer?

5. Use larger Copper Tubing more copper tubbing?

More Cooling surface area?

Though its not the hottest of the season I really want this to work at this point just to see it work and have the satisfaction of having it work. Yeah its bad enough my room never goes below 80 (and I hate warm) but I have invested alot in to this so any advise is apreciated

ehensel1 (author)Alamarus2014-06-02

My first thoughts about the condensation go directly to the ambient humidity in the air. CO is generally less humid, and being that the room is right next to a furnace, you could just have less humidity in the air. To test this theory, grab a glass of ice water, and just let it sit for a little while in the room. If there's no condensation on the glass, it stands to reason that you're not going to see much, if at all on the copper coil. This does not mean you're not getting heat transfer. Your build looks very solid, and should be working just fine. Let me know if this helps, or if you make any tweaks that do.

Steffenmatt (author)2014-05-27

I also had try this it's working quiet well.

John Culbertson (author)2014-05-16

If you really want to supe this up you could do the following:

1. Switch from an ice bath to a Ethylene Glycol, Ethanol, and dry ice slurry

2. This would require a different pump; a homemade peristaltic pump should do the trick.

3. Then just swap out the basic Vinyl tubing for some tygon tubing that can go down to -100F

I am very tempted to build this for field use in the Mojave desert this summer.

Note: this is very dangerous on nearly every level. The Ethylene Glycol (AKA anti-freeze) is poisonous and sweet, so keep away from pets. The Ethanol is of course flammable, and of course you would be pumping this through a system with at least two brushed DC motors, so leaks could lead to fires quickly. Hmmm... maybe this isn't such a good idea after all.

ehensel1 (author)2014-05-16

That's awesome! You even took the time to bend the copper all nice, into a circular shape. With the fan constantly blowing, you shouldn't have condensation problems, unless it's really humid out, but if you do, let me know if you come up with solutions!

John Culbertson (author)ehensel12014-05-16

Bending the copper tubing was actually really easy because it already came in a coil about the size of the fan.

So far I have had no problems with condensation and don't expect any, it is to dry here is SoCal.

hilldomain (author)2013-07-10

wouldn't adding a block of ice in front of the fan do the same job?

bryan3141 (author)hilldomain2014-01-08

the cool air this produces should also be at least slightly drier (see the discussion of condensation in other comments) than the surrounding air rather than slightly damper as it would be if you used ice directly.

hilldomain (author)2013-07-10

is there a risk of a short or electricution with the fan motor and condensation issue?

club81 (author)2011-03-19

Doesnt your ac make alot of condensation???

monamontgomery (author)club812011-09-02

I am trying to figure out a way to keep the condensation from becoming a lake in my living room. Maybe I'll find a way to drink it.

put a tray under the fan with a hole in it and stick the whole thing back on top of the cooler to drain into?

robcull (author)monamontgomery2013-04-24

An easy quick fix for condensation making a mess is to direct it with a piece of string. A water droplet will run down a string (like sewing thread) as long as it's at a steep enough angle; almost like a wick. If the condensation is beading up and dripping off of a particular point on the tubing, tie a piece of thread there and run it down to a bucket/pan for collection. Then, at least, it won't be pooling up on your floor.

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