Cheap-o Homemade Air Conditioning (Dog Not Included)




*This is my first instructable;sorry if it seems over simplified and shoddy. None the less, the project itself is very simple and can easily be modified in a number of ways to fit one's needs and or materials.*

The problem:

The air conditioning in my apartment is horrid, and I can't expect my slum lord to fix it. I'm rarely home so the idea of running the a/c all day to have it slightly less hot than it is outside when I get home is not worth it. Not to mention I don't have the financial means to pay exorbitant utility bills. I would just sweat it out, but heat + electronics & instruments don't mix.

Possible solution!?

Homemade A/C for about $15 (give or take depending what you have laying around and how far you want to take this project).

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Step 1: Materials & Basic Idea


Styrofoam cooler

Ice packs

x2 Fans (one medium size fan would work as well- it all depends on your cooler size and how many fans you want to fit into it)

Knife or some cutting tool- if you want to get fancy and feel high tech go ahead and break out that hand held rotary tool.

Over arching idea:

A Styrofoam cooler with ice packs in it. Holes are cut into the top to place fans. The fans will draw in the cool air and shoot it up.  Basic idea that cool air falls and will hopefully make the room a little more tolerable.

Step 2: Start by Cutting It Out

I'm not too good with keeping it witty. This title is probably the best you'll get and if you're still reading and didn't ADD click one of the side ad's about whiting you're teeth with LED's... I'll keep it short and sweet; in other words put a lid on it and get on with this wall of text.

What we're doing here is cutting holes in the lid to fit the fans in. I found it easiest to keep the lid on while cutting that way all the Styrofoam bits fell into the bottom of the cooler and was easier for clean up.

If you feel a need to put those math skills to work I'm sure you can calculate the circumference and throw in some diameter action. Then figure out the right micro watts to set your laser to so not to set anything on fire while cutting with it.

I just simply set the fan on the lid and did small pokes with a knife to make an outline for the fan shape. While cutting, I tried to cut at roughly a 45 degree angle so the fan didn't just fall into the hole. Think about it as carving a pumpkin and when you are making cuts to take the top off.

Remember you can always make the hole a little bigger with additional cuts.

Step 3: Assemble!

Get your hard hat, safety goggles, gloves ect. and make sure to review proper lifting techniques.

Take your fan and insert it into the hole(s) made.

Step 4: Ice Ice Baby

Fill up the cooler with ice packs~!

Uh oh no ice packs? No problem, fill up some plastic bottles and toss them in the freezer.

Step 5: Chill Out

Close the lid, plug in the fan(s) and kick back with a glass of lemonade.

Step 6: Potential Upgrades

As stated in the beginning this is a very simple illustration of an idea that can be taken further. Over all, it works pretty well for a small room. Although, not enough that I think I'll be wearing a sweater in my room anytime this summer.

Some items that could potentially make it better:

Possibly using a coolant + water mixture in 2L bottles and freezing? (~70% H2O & 30% coolant)? Not sure if that would work as desired- I'm assuming coolant would have a higher heat capacity than water and therefore stay colder longer? Careful with coolant around pets!

Make some sort of copper piping lattice to freeze and put into the cooler? Hmm... I do have access to liquid nitrogen...

The fans I used were some what weak and took a bit to get air circulating in my room before I noticed a difference- I've been thinking about replacing my fans with stronger ones

To make the fan installation more permanent feel free to throw in some hot glue. Personally, I like the idea of being able to take my fans out if I want to.

Using a plastic cooler- I have a few Styrofoam coolers myself that I am trying to put to work instead of having them sit in a land fill though. But a plastic version might be more durable and tighter seal around fans.

Add some LED's that always seems to make stuff cooler *ba dum tish*

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11 Discussions


4 years ago on Introduction

now you just have to move the fridge out of the house for this to work..


6 years ago on Step 6

Coolant actually has a lower specific heat than water does; thats why you must not use it full strength in an automobile. Its purpose is not to cool better, its purpose is to prevent freezing and boiling, corrosion prevention, and pump lubrication. Nothing beneficial for this project.

Open up some vents to allow cross-circulation, your fans are probably fine if they aren't starving for air.

Using salt will lower the freezing point; but not the temperature. Water(ice) will attain the temperature of the freezer even though it has frozen - its not helpful to keep it in liquid form. It doesn't simply stay at 32 degrees just because it turned to ice.

Freeze the ice during cool periods; otherwise your freezer is simply returning the heat to your house as it re-freezes the ice. Factor in in-efficiencies, and you'll actually be making your house warmer.

Consider a programmable thermostat - you can have the A/C turn on an hour or so before you get home; thus be more comfortable but not have to leave it running all day. You might even present it to your landlord as a cheaper solution to fixing the system and get him to pay for it!


6 years ago on Step 6

Very nifty idea. I like your writing style!


8 years ago on Introduction

Very clever idea. I have thought of this for my metal shed-shop to supplement my swamp cooler, but never put anything together, and i have some small equipment fans around.

BTW when i take soft drinks to a the Amateur Radio club i belong to, i take four two-quart bottles of water that have been in the freezer and they fit into the bottom of the cooler. Then i put the 32 cans of drinks on top of that. Lot less messy and expensive than bags of ice cubes. I suppose You could also use a stack of frozen water bottles in this idea. Perhaps salt water might be even cooler.


8 years ago on Step 5 one fan blowing in and one blowing out? I mean where is the hot air coming in to the cooler?


8 years ago on Introduction

you're joking, Right?
Ice yields 977 btus/lb.
you would need to melt 5 lbs/hour to make much difference at all!


8 years ago on Step 6

Great, simple Instructable !

Here are a few ideas to try:

1.) Try plastic bottles set upright along the bottom of the Styrofoam cooler. That will give you more cooling capacity.

You will have to experiment with the number of bottle since water will collect in the bottom of your cooler.

Also, keep the bottles a little apart for more cooling surface area.

2.) Maybe put table salt in the bottles to lower their freezing point.

3.) Make the holes for the fans a bit bigger for better airflow.

4.) Try reversing one fan to blow into the cooler for better air circulation.

5.) Maybe cut slots on two sides of the cooler and reverse both fans to blow into the cooler.


8 years ago on Step 6

If you use Salt Water it will cool lower than regular water. That is how home made ice cream works.


8 years ago on Introduction

we simply place the fan just above and to the side of the cooler. works great. though your apparatus insures the ice packs stay frozen longer


9 years ago on Step 6

try using teething rings or the liquid from them. it takes awhile to freeze but stay cold for awhile when they arent in a babies mouth


9 years ago on Introduction

I can't tell from the photos but I assume one fan is blowing in and the other is blowing out? So why two fans? If they are both blowing in the same direction how does the air get in or out?