Picture of How to Build a Soda Can Heater
Soda Can Solar Space heater

This is a basic "how to" on creating your own soda can space heater. Several videos can be found on the net, but none of them really provide a step by step guide. I put this entire unit together with about 10 total hours of actual labor. If you have a source of cans, lumber, and a old double paned window (preferably), you can assembly one of these yourself. 

Required Materials
• 1 window, 46.5 " L x 23 " W (recycled/freecycle, double paned)
           o The selection of the window will dictate the number of cans required for the array. 
• For this size window, the number of soda/beer cans required is 72.
• 4 x (1 x 6) boards (not pine or poplar).
• Board Insulation
• Great stuff foam insulation
• 2 x 2.5 inch vents (bottom intake vents) 
• 1 x 3 inch vent (top)
• 3 x 4" squares of screen material
• Metal Duct Tape (for can assembly and final sealing) 
• 1/4" plyboard (for the back of the box) in this case the measurement is 2'x4'
• Black spray enamel (about 2 cans is sufficient for a 72 can array and painting the box. )
• 3 v computer fan. 
• 3 v solar cell (s).
• screws
• brad nails

 Required Tools
• Screw Gun
• Tin Snips
• Brad Nail Gun
• 2 and 5/8 inch hole bore drill bit.
• Hand saw or Circular saw
• Jig Saw
• Clamps     
• Square
• Tape measure
• Pencil    

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jmwells9 months ago
I built one similar to yours. In front of, and on top of the insulation I put a piece of wonderboard. It lengthens the cool down period, and seems to store enough on most nights to not have a full cold start in the morning. Thermal mass is wonderful.
falling_stone (author)  jmwells9 months ago

this is a crazy good idea.

Works for me.
Costarus made it!9 months ago

I built a similar device... In 2009, I used sealant that would connect banks. The volume of received about 40 liters. Water is heated to +85 degrees Celsius. The heater worked all summer. But in autumn it dropped from the roof of the hurricane. I did not recover. Invented more efficient heater. (sorry, machine translation)

eegryglak13 days ago

I am mentoring a sophmore student who wants to build a solar heater for her sophomore personal project using your instructions. We may need your help along the way since I teach Chemistry and have limited understanding of electricity and electrical panels. First question: I was looking into the 3v solar panels on Amazon there are several 3v panels but they have different mA. Which mA are best or required for this project?

falling_stone (author)  eegryglakyesterday

Hey Eegryglak, this is a great project, make sure your student has a good undestanding of powertools (i'm sure she probably does) but there is some minor working with this project. Safety glasses! Also, with your student make sure her cans are SODA cans.
Ok, so in my project, I selected the 3v fan because that was how much juice I could get out of the modest solar panels I had available. They both kick out just about 2.5W .

Lets make this part of her assignment:


Volt: electrical potential

Amp: Ampere; the current;

So, lets do questions:

What is the voltage output her solar panel? ___________

How many solar panels will she have? ______________

How much current can her array produce?

Lets do an example! Let's say you had this solar panel: (3.5w 6v USB Mini Solar Panel)

And lets say you have a Fan to run, so how many amps can your solar panel put out?

You'll calculate though the relation: Watts = Amps x Volts

You get 0.583 Amps or 583 milliamps. This is the least output that your solar cell needs to run your fan.

Biofoodlady3 months ago

Why bother even putting the frame outside. Just use a real window as the frame, then you have an instant radiator too. I am going to try this in my art studio - sod the natural light, I want to be warm in winter! Do you reckon I should use wood for the back panel or a metal panel?

I'm wondering if you ended up doing this the way you proposed here in your comment. I had the same idea to make smaller panels that would be sealed against my double pane windows using weather stripping so I wouldn't have to attach anything to the house. I'd be really interested to see your design/photos and hear about the results. I'm also wondering, more generally, if anyone has an idea of what the ratio of size to output is. Obviously more surface area, more air/convection/heat output but at what point is the panel too small to even make a difference. The design I'm mulling would use some wooden trays that are 24"x13"x4", enough to fit some insulation and the cans, but I have concerns about efficacy at that size. I'd really just like to use this as a supplement to the house's heating during the day.

I saw a lady at the county fair making a solar shed with plastic water bottles. The sun goes right through but the plastic retains the heat so you can still have light in your window. I've also see plans to fill them with water. I want to do this in one of my sunny windows too.

falling_stone (author)  Wepwopper2 months ago

if you're going to use water, make sure you include an algecide. Otherwise, you'll end up with green growing in your bottles :D

I'm re-thinking the water angle. It gets took cold up here. Maybe a water tower inside a sunny window would work to retain some heat after sundown.

ntinumirov9 months ago
sorry i do not understand.... why do you need to heat soda cans?? do you need to heat water? take plastic pipes.. black one.... black rubber hose...

I've been thinking the same thing. I've seen guys use that corrugated plastic board for this. I've also thought of using metal pipes or reversed metal panels painted black.

falling_stone (author)  Wepwopper2 months ago

both would work. though if you're going ot use water, you may want to include an algecide

falling_stone (author)  ntinumirov9 months ago

it's a language difference, the soda cans make the heater (so: Soda Can heater).
Like Paper Airplane. Or an Airplane Made out of Paper.

It's used to heat air in a room with a sunshiny window.

jvangurp2 months ago

Why not use pine or polar? I'm going to fine tune a model and then buy a microcontroller from these folks to run the production models attached to the house:

falling_stone (author)  jvangurp2 months ago

good luck!

Sun_web8 months ago

Living in the sunny and warm state of Florida, I am thinking of trying this as a reverse process. Instead of hanging in the sun to collect latent heat, I am considering burying it and running the air through to cool the air down... Any thoughts/suggestions?

Wepwopper Sun_web2 months ago

Then the solar panel and fan would be set up to turn on when it is hot to draw the cool air up. ;)

falling_stone (author)  Sun_web7 months ago
A heat exchanger, you need a cool place to vent the heat into in order to get the efficiency. This one vents the heat to where the people are. Many places actually do what you're describing, but they have to go a bit deeper than this unit size in order to get to the cooler temperatures available in caves/deep underground. I know in the summer where I am, I can get cooler air in my basement, which we can pump into the main living space. If you had a tube of sufficient length, you could run it underground, cool the air, and get it back on a return loop and it concievably would work. If you are interested in using the sun to help cool you off, you might consider looking into a solar panel and a battery bank that supports an air conditioner
vincent75208 months ago

BTW your wine cellar is way too hot : it should be within 46 and 53 at the most !!!…

Don't do upon your wine what you wouldn't accept being done upon you ;)

falling_stone (author)  vincent75207 months ago
That's true! I moved and now have a home that has the appropriate temperatures for my wine. At the time of this instructable I was in a humble townhome with a small crawlspace that I jokingly referred to as the winecellar :D
thuber69 months ago
where are you going to place this at?
falling_stone (author)  thuber69 months ago

So, this one is an older build, and kinda heavy. I used to put it in front of the sliding glass door (the non-moving panel) and it would make heat all morning. Now this old guy's getting fitted for putting into a chicken coop I'm planning. But the other day I had my furnace replaced and I pulled this old guy out and it made heat for me in the afternoon while I waited for the repairs to be finished.

craftclarity9 months ago

I clicked on this because I was curious as to why one might want to heat soda cans, only to find what is actually a really cool project! I wonder if "Soda Can Space Heater" might get more attention...Nice work! I might try and build one for my house.

simi-kilr1 year ago
Nice set up. where do you get the solar panel from?
falling_stone (author)  simi-kilr1 year ago
RadioShack I think.
jakdedert2 years ago
Is there a reason to restrict airflow through the tube (by not cutting out the entire bottom of the can), or what it just easier?
Hi I think "Mladen_solar" (another user who did more or less the same project) explains about the holes quiet well. He recommend to make the holes irregular to cause more turbulence in each can. This cause more of the air to touch the warm surfaces going through the cans, resulting in more transfer of energy. I can't prove with numbers, but it seems to make sense to me.
(It's possible you need to follow his link to find the reasoning for the holes)
It comes down to air residence time within the column for sure.
falling_stone (author)  jakdedert2 years ago
I think there is a good reason to restrict/control the air flow in and out of the unit (and again this is thinking, I haven't actually proved this to myself yet).

If you increase the residence time of the air in the unit (by restricting the air flow), you give the air more time to heat up. If the air runs too quickly through the unit, you won't get as much heat from the unit as you might.

But if you restrict the airflow too much, you run the risk of the unit overheating. The unit can get very hot in direct sunlight. Depending on your situation, you could modulate this with a stronger fan (or even an intake fan) to really control your residence time.

I'd be interested to see if you could build a smaller version that could heat the air up more or a larger unit that could heat the air up a little less and see if that could be used to deliver the right temperature of air.
jmicari3 years ago
looks like a thermaltake fan, can you tell me which models, newegg doesnt have enough info, and when they do it seems they are all 12v. Thanks
falling_stone (author)  jmicari3 years ago
It's actually a computer fan, that requires about 3.4 volts to run. I've since added another small solar panel so it will fire up more easily on a cloudy day.
Radio Shack:


Just run on down to your local computer supply store and tool around. I'm sure you'll find one. Good luck!
lukeyj153 years ago
With your baffle idea, you could use heat sinks to heat the inside of the box. Have a box like you have, but use black heat sinks instead of aluminum cans.
falling_stone (author)  lukeyj153 years ago
i like this idea as well. So, you'd essentially put air chambers around the heat sinks?
Yeah. I was thinking that you could make tubes like this out of metal
| | |
| | |
| | |
| | |
| | |
| | |
| | |

In a U shape, connecting the Us with another upside down U

Attach them together with heatsinks attached to the insides of the tubes.
falling_stone (author)  lukeyj153 years ago
Alternatively, you could use heat sinks inside the can tubes, there is a surprising amount of room on the inside. You could take your suggestion and use wire to suspend the heat sinks inside of the tubes.

When I build my next one I may have to steal your idea ^_^
It's not stealing if I put my idea into the public domain.
The formatting in that didn't work, but you get the idea.
Dr.Bill4 years ago
I had an idea like this when I lived up state NY.

I had No idea it produced this much heat.
Have you experimented with a higher volume of cool air to determine what temp the unit will drop to.

You can control the speed of a nice squrril cage fan with a light dimmer to experiment with air flow (CFM) to heat output ratio. This might turn out to be a saleable product.
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