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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jmwells1 year 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.

Hi, Thanks for the idea! Are you still getting optimal results from the backer board addition? Noticing any problems with it or any suggestions on ways to improve? Thanks!

falling_stone (author)  jmwells1 year ago

this is a crazy good idea.

Works for me.
Costarus made it!1 year 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)

smurray2 made it!1 month ago

I built a slightly larger one for a big barn. I also added a small solar PV panel connected directly to a 4" PC fan mounted over the inlet duct, this means that on very sunny days the fan pushes the air through the system faster and so indoors doesn't get too hot, the sunnier the day, the faster the the fan spins and so the heat from the panel is not as intense inside.

dan30082 months ago

mmm, I'm intrigued to try this :) My greenhouse gets rather cold during the winter, and it would be nice to try and keep it above 0c for the sake of my plants in there :)

falling_stone (author)  dan30081 month ago
that's great! if you're going to use this unit design outside, you'll want to polyurethane it so it's weather proof. As it is, this was designed as an inside unit. I'll be taking this very same one and uing it to heat my chicken coop this coming fall and winter.
jevans704 months ago
Hey, this is great I built one using this guide. But.... you actually get hotter air without the pc fans. Noticeably hotter. I'm thinking as the air moves slower it has more time to heat. It naturally rises as it warms as we all know so it so pulls in more air as the hot air leaves at the top.
falling_stone (author)  jevans703 months ago

without the fan, you will run the risk of fire. I'm SURE it gets hotter without the fan. I'm just afraid to set it up and leave it unattended. :D

Just wondering, this may sound WOEFULLY ignorant and I apologise but I'm not particularly sciencey- but how good is this in winter? I am only thinking because both metal and glass get very cold from the air temperature? I am looking to convert an old van into a motorhome that is as self-sufficient as possible- I live in the UK and it gets to around -5 in winter. :)

falling_stone (author)  amber.guenigault5 months ago
This is a good question, the box itself is insulated with foam insulating panels. The heat is captured black paint on the metal cans from incident solar radiation. The heated air will pass through the cans and out the outlet bringing in cool air which will reside in the unit until it's hot enough to come out the top. You can see the relative temperature differences in the attached picture. It was 60F that day, and we were able to get the unit to produce hot air up to about 150F in direct sunlight.
paulpaul6 months ago
Money and Time saver. When you've cut off the closed end of the cans & you're ready to assemble, place the can, open end down, in a pan with couple of inches of boiling water. The Aluminium will expand enough to slide it onto the next can, and when it cools will clamp (air) tight.
falling_stone (author)  paulpaul5 months ago
That's a great suggestion!
Zachmil13997 months ago

What are the item numbers for the materials listed?

My teacher said I need specific item numbers.

falling_stone (author)  Zachmil13997 months ago
You can define what you need specific to your design. The point of this project is making something you need to your specs.

There are links throughout the comment section and within the document that provide direction to where I obtained the items, like the Fan.

Radio Shack:


Much of the items I had lying around, except for the window, which I got from the Salvation Army Home Store.

good luck!
ntense998 months ago

How is this one working out for you? I built mine to fit on the inside of my windows. Here is what mine look like if u r interested. They work really well!

falling_stone (author)  ntense998 months ago
So, this one is retired right now, It's destined for the chicken coop as a an addition to the heating system. The barrel stove has made the need for this old guy obsolete. But I still have a use for him. :D
ntinumirov1 year 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 recently seen this built with regular fruit/bean cans (holes drilled in the bottoms) or coiled dryer pipe. I have the cans but still need to get the solar panel.

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)  Wepwopper11 months ago

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

falling_stone (author)  ntinumirov1 year 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.

eegryglak9 months 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)  eegryglak9 months ago

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:

Watt: http://en.wikipedia.org/wiki/Watt#Examples

Volt: electrical potential http://en.wikipedia.org/wiki/Volt#Water_flow_analo...

Amp: Ampere; the current; http://en.wikipedia.org/wiki/Ampere

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: http://www.amazon.com/dp/B00HQY7GDC?psc=1 (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.

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)  Wepwopper11 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.

jvangurp11 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: http://www.greenhillenvirotechnologies.com/products/about-the-okapi-systems

falling_stone (author)  jvangurp11 months ago

good luck!

Sun_web1 year 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_web11 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_web1 year 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

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)  vincent75201 year 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
thuber61 year ago
where are you going to place this at?
falling_stone (author)  thuber61 year 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.

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.

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