Introduction: How to Build a Soda Can Heater

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    



Step 1: Cans and Manifold

Picture of Cans and Manifold

Step 1

Consume beverages. Yes, you have to drink all the beers/sodas to make this heater, though alternatively, you could collect them. Whatever the method, it is important that the cans are in fairly good condition, free from dents, cracks, or tears.

After you’ve collected the requisite amount of cans, you should sand the surfaces of the cans, both to remove the paint with sandpaper and to roughen the surface so as to make the paint adhere more easily to the can.

The cans are needed to assemble the metal heating tubes. The cans will be assembled end to end, so punch a hole into the bottom. Use the punched hole to make a series of cuts with the tin snips to create a  baffle between each can.  Also, cut or break the pop tops off the cans to make stacking better.

Step 2

Once the cans are sanded, the array must be planned. Place cans side by side along the bottom board, leaving a small space between each can. Draw the outline of the cans on the bottom board to make the first manifold. Provide enough space from each edge to make sure the board will not break when drilling the can-sized holes. Use the 2 5/8 inch hole drill bit. Use metal tape to shore up the borders between the can holes as the drill will likely create thin walls between each can hole. 

While you are drilling, you can drill the holes for the vents. The top of the box will house the single 3" vent. The 2 smaller vents go in the bottom of the box. You can set a square of screen material over the holes before you press the vents in, which will help to keep insects out of the heater when it is finished.

Step 2: Can Towers and Box Construction

Picture of Can Towers and Box Construction

Step 3.

Once the bottom manifold is correct, use it as a template for the top manifold and create the box necessary to hold the window. Be sure to match the pattern left to right so that the can tubes line up and run straight within the window box.

Using the 1 x 6 boards, create the frame from the box for the window. Measure the boards to ensure that the window will fit snuggly within the frame. Once framed, screw the plyboard to the back of the box. Spraypaint the interior of the box with the black enamel paint, and cut in the insulation board necessary to fit the box. Be sure to leave enough space at the top of the box to create an air chamber into which the manifold will vent. The cans can now be assembled into tubes. 

Step 4.

Each can tube should be the same number in height. For this window example, each of the eight can tubes will be 9 cans in height. Use the metal duct tape to assemble the cans into 9 can tube towers. Paint the can assemblies with black enamel paint. Make sure that the cans do not go all the way to the top or the bottom, a small chamber should exist on the top and bottom of the manifold to collect and exhaust the air.

Step 3: Final Assembly and Testing

Picture of Final Assembly and Testing

Step 5

With the can tubes put together, you can now progress to final assembly. Carefully fit the painted, taped can tubes through the bottom manifold into the top manifold. Special caution should be taken in this step as rough handling will break the tape seals in the can tubes. Final assembly should have both the top and bottom boards holes drilled and vents installed. 

Ensure to test the assembly for effective heating before finishing the insulation and sealing the system. 

Step 4: Sealing, Insulation, and Clamping

Picture of Sealing, Insulation, and Clamping

Step 6

After testing the final assembly, you can now finish the box.

Install the top vent and bottom vents into the pre-drilled holes.

Seal the insulation and cracks with the Great Stuff foam insulation. Be sparing with this insulation as over application will cause too much expansion and could damage your cans. Put beads of the great stuff foam insulation on the face of the boards, to act as a glue for the window.  Then use two sets of clamps to set the window into place. Using the metal duct tape, seal the window into place, and seal any cracks or edges around the outside of the box.

Step 5: Solar Powered Fan

Picture of Solar Powered Fan

Step 7

Create a solar vent fan that will assist in drawing hot air out of the solar heating assembly. Cut the computer board fitting from the computer fan, and splice with the solar cell (like wire colors). Use black electrical tape to finish the splicing. Place the solar fan just above the top vent, with some spacers that will allow the fan to spin freely.

Ensure to affix the solar cell to the front of the unit so that when the sun hits it the fan will engage.

The more direct sunlight the unit gets, the more efficiently it will operate, and the more free heat you can pump into your space be it your home, your green house or your man-cave. 

Good luck!!

Step 6: Further Refinements

Picture of Further Refinements

after a few years of sporadic service, it was the time to use this unit outdoors for a more permanent purpose. a coat of weatherproof paint and some ducting coupled with the old computer fan housed within a waterproof unit and all of it typed into my chicken coop. the unit is made to face south to take advantage of the winter sunlight. I taken some great stuff foam insulation and made sure that it was nice and tight inside. during the day the chicks will get a nice push roughly 35 degrees centigrade air to keep them a little more comfortable in the winter.


jmwells (author)2014-02-07

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.

cwallace0025 (author)jmwells2015-03-22

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)jmwells2014-02-10

this is a crazy good idea.

jmwells (author)falling_stone2014-02-10

Works for me.

Costarus made it! (author)2014-02-09

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)

jvangurp (author)2014-09-08

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)jvangurp2014-09-08

good luck!

I also need to know why not Pine or Poplar? Is it too weak or expands and contracts too much?

jevans70 (author)2015-04-28

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)jevans702015-05-04

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

Hi, couldn't you use a thermostat to turn the fan on when the temperature got above a certain temperature? This would keep it from overheating and causing a fire.

Kbquoi (author)2015-12-27

here's the fan.

Kbquoi (author)2015-12-27

Here's the fan.

PatQ2 made it! (author)2015-12-15

well I tought of retrofiting a framed doule glass window into a heater too, my particular challenge: the unit has to go on the roof to get sunlight exposure, so I needed to suck the heat back down then move it another 10 feet on the side and down to a window.... still working on it though. I am using one of the pop can pipe to travel the heat back down from the top.

falling_stone (author)PatQ22015-12-21

you can get a 4" ducting fan for this application. You will want to insulate your travel line to ensure you keep the heat you've gathered until you get it to where you want it to go.

Kbquoi (author)falling_stone2015-12-27

Thanks,I went 3" all the way to the connection in the window where I enlarged to 4" so I could use a rectangular heat trap fan. I also insulated the docking, 10' of which is made out of an old 3" pvc gutter down spout.

excuse my video in French.

Kbquoi (author)2015-12-26

French video.

I went 3" ducking, insulated, all the way from the pannel to the connection in the window, where I enlarged to 4" so i could use a rectangular heating trap fan.

Left-field Designs made it! (author)2015-07-22

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.

looks great!!!!!!

amber.guenigault (author)2015-02-26

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. :)

Come to Montana summer 2016 for the Missoula College Energy Practicum.

that sounds like fun.

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.

emazza00 (author)2015-10-21

How Can I measure how much heat it generates?

falling_stone (author)emazza002015-10-26

Measure the temperature of the incoming air.
Measure the temperature of the air that is coming out of the top.
Depending on how much sunligt you'll get and what kind of fan you'll rig to it will have an inpact on the output.
I recommend using something like this to get your temperatures.Once you know your temperature difference you can use a physics equation to determine the actual heat transferred.

emazza00 (author)2015-09-16

I have a question on how to make this at home, I want to build this however, I want it to be smaller. How do I know what size fan to get, and where to I get the fan, I want my version to by 32 by 23 I believe.?

falling_stone (author)emazza002015-09-21

At home you will need tin snips, a small saw, and black paint.
You can get the fan you need and the solar panels online or at RadioShack.

swanie9 (author)2015-08-31

Could this be altered to mount on the outside of a window, removing the fan and just letting heat free flow into a house through an open window?

falling_stone (author)swanie92015-09-09

Certainly could, but you want to be real careful about how much heat it will build up, you might want to consider which materials you use. The fan helps to cool the unit as much as it pushes heat into the area you desire. Also, I was reading that they work better if you have a greater temperature gradient from the cold air to the warm air.

dan3008 (author)2015-06-30

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)dan30082015-07-07

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.

paulpaul (author)2015-03-01

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)paulpaul2015-03-03

That's a great suggestion!

Zachmil1399 (author)2015-01-09

What are the item numbers for the materials listed?

My teacher said I need specific item numbers.

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!

ntense99 (author)2014-12-28

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)ntense992014-12-29

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

ntinumirov (author)2014-02-10

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...

Wepwopper (author)ntinumirov2014-11-29

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.

Wepwopper (author)ntinumirov2014-09-03

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)Wepwopper2014-09-08

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

falling_stone (author)ntinumirov2014-02-10

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.

eegryglak (author)2014-11-12

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)eegryglak2014-11-23

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.

Biofoodlady (author)2014-08-16

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?

dtfathedza (author)Biofoodlady2014-10-27

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.

Wepwopper (author)Biofoodlady2014-09-03

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)Wepwopper2014-09-08

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

Wepwopper (author)falling_stone2014-09-08

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.

Sun_web (author)2014-03-28

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?

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Bio: Building things to pass the time and sharing the good ones with others.
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