There are hundreds of different DIY passive solar air collector plans floating around, but I’m focusing on a few that incorporate recycled aluminum pop, beer or juice cans as the “solar absorber“.
These DIY pop can solar panels are inspired by Cansolair – a commercially-produced product invented by a man from Newfoundland, Canada.
The Cansolair panels are well-engineered, and use materials with the most efficient thermal performance – as the hefty ($2749.00) price would suggest.
What’s Passive Solar Heating?
Passive solar air heating is considered the most cost-effective renewable energy – utilizing the energy from the sun by capturing it with an absorbing medium. There are plenty of online sites dedicated to passive solar applications, but you can get the basics via Wikipedia.
Passive solar heating intrigues me. It’s the only “free” heating source that I can think of. If it worked at night, it would be perfect.
Crowd Sourcing a Design
I intend to build one of these at some point and my research has turned up several designs and methods of construction – from very well executed to the afternoon “garage experiment”.
After spending several hours sorting through many pages of Google results, I’ve narrowed it down to a selection of results that’s representative of the designs, methods and materials DIYers are experimenting with – from good to bad.
A couple of these show up repeatedly in just about any Google search related to pop or beer can heaters (the Red Garage Project for example). I’ve included what I feel are the best designs that merit a look and some interesting ideas that you could adapt for your own purposes.
I know mine will incorporate the best ideas taken from the designs highlighted below.
Here’s what’s out there
1. Solar Panel out of Aluminum Cans (by Malden P)
This design most closely resembles the commercial product sold by Cansolair. The site has very good pictures and step by step details to build a full-size passive solar heater.
Rating: Excellent Design. Definitely worth a look
2. Beer Can Solar Heater (by bornonazero)
This is a similar (and very well executed) design originally presented as a pictures-only You Tube video. There’s also an updated video with a bit of descriptive narration added.
Rating: Definitely worth a look.
3. Greg’s Pop-Can Solar Space Heating Collector (Greg West)
This design on “Build it Solar” is excellent. The PDF download is very detailed with good pictures. It features aluminum plenums in a box made of polyiso rigid insulation and has a flat face of Twinwall polycarbonate glazing. Lot’s of good ideas in this one.
Rating: Well worth the download (3MB PDF).
4. The Ubiquitous Red Garage Project (link no longer available)
This version pops up in a lot of searches which is really frustrating because it’s not a good design and it probably turns more people off the idea than it inspires. I have no idea why so many sites linked to it or posted about it.
The design has efficiency deficiencies like no plenums – meaning the air doesn’t pass through the cans – which is kinda the point, and what produces most of the heat.
On the plus side, he built a second, larger version and I have to give him props for recycling a patio door for the glazing.
Rating: Take a pass or give it a quick scan and move on.
5. Colorado Wind Power (link no longer available)
This one is a bit crude in the approach, but it would be fast and easy to do. However, I’m not so keen on the idea of superheating Styrofoam and pumping the resulting off gasses into my home.
The best takeaway from this one is two unique methods to make the holes in the can bottoms:
• using a blow torch (which would be pretty much instant)
• using a belt sander, which takes out the full bottom cleanly.
If you needed to MacGyver one of these in an emergency, then this would get you there. If you’re going for a longer-term installation, keep looking.
Rating: Have a quick look just to say you did.
6. Brian’s Pop Can Solar Heater
This one is kind of in the middle of the pack – the functional design looks to be sound, but it loses points on the fit and finish.
If I’m going to invest the time and energy in building one of these, I want it to look good and be reasonably sure it will stand up to the extreme conditions it will be subjected to.
Brian does provide some performance data that shows what kind of results you could expect (in Alabama).
Rating: Look it over for ideas to use.
7. Stonehaven Portable Passive Solar Air Heater
This is my own design and first try at building a solar air heater to try here at home
My partner and I both work at home, but our offices are in different areas of the house – a couple of portable “space heaters” would be more likely to keep us comfortable than a single large one located in the only practical location, which is a long way from my office.
Wrap up
Passive solar heaters make sense and are an excellent DIY project that should pay for itself in a year or two. There are a lot of good ideas in examples above but the main points to consider carefully would be:
- High internal Heat – use components that will stand up to repeated extreme temperature swings.
- Insulation – avoid or cover Styrofoam insulation that could offgas or degrade due to UV exposure.
- Location – maximum southern exposure during the warmest part of the day
The pop can heater is just one of many types of passive solar heating installations. I’ll explore other designs in the coming months.
Related posts on this site:
Comparing Solar Air Heater Designs & Performance
Solar Heat: Free for the Taking
Earthships: Sustainable & Self-Sufficient Living
Superinsulated House Design
Home Energy Retrofit Economics
Add Flexibility to Plastic Window Kits
Yes, I’ve been looking for the same thing, with the soda cans standing straight, instead of stacked. I think the Mother Earth News had that in one of their issues years back. I know it works, because it had a space underneath the cans where the cooler air from the house would go in and down to the bottom, and a space where thair could go from the cooler air at the bottom, and up and thru the cans and back into the house. NO MOVING PARTS!
I saw something similar to the soda can unit you described many years ago and I doubt it would really work at all.
Some years ago, I saw a window collector made of soda cans, but in this one, the cans were standing upright, as singles crowded together. I can’t find any site that tells me how to do this, and just stick it in a window, without having to cut a lower cool air intake.
Any idea how much the “space heater” solar works? I don’t really want to build a frame or anything for my window I was just wondering if I could build one that would work indoors
Rivi
I don’t know what size you need for that space but you’ll find a lot of valuable info that should help at builditsolar.com.
Good luck.
Hi!
I’m trying to figure out the size I should do the solar can heater. I’m trying to heat a space that is 800 Sq feet, how big should the solar can heater be?
I cant really find sizes online.
Thanks!
Rivi
I have been using soup cans (tesco), tins of frankfurter/hotdogs, and a separate small system using minicans (eg 150ml ginger ale cans). I soak them in boiling water and use an old toothbrush to clean the debris. Used matt black spray paint. Exploring effects of differing hole sizes – slower air flow seems to increase the resulting heat. Haven’t figured out what to use as an enclosure yet, so have them as stacked cans which heat up windowsill and then leaks back into lounge. Have other separate stacks for kitchen and bedroom windows (as have east-west facing windows). Have thick curtains with fleece liners and double glazing – lounge temp circa 20C, windowsill roughly 12-15C, and during daylight, inside a stack of 6 cans am getting 5C temp boost relative to windowsill. (External temp circa 7C – a mild winter at the moment in UK). Expect higher boost when all stacks are feeding into the same output hose (using tumbledryer waste heat pipe), with my eventual enclosure, and glued together. Also going to use narrow gauge hose to feed/suck cool air into the windowsill from floor level.
Sandi
I’d be leery of using cat food cans for a solar heater since it would be nearly impossible to completely clean the meat residue from the inside of the cans. Blowing hot air into your home through all those cans could be unhealthy.
I want to do this, but I want to use cat food cans. I think they would be even more effective. With about 6 or more holes in the bottom of the cat food can and each one varied in position it would get even better ventilation. Plus they naturally lock together.
Solar panels
I still still haven’t gotten around to building one (or two) of these yet but I have salvaged a fan from an old PC and I’m working on my soda can collection.
Rick
Thanks Monty. I imagine you have a lot of these installed in houses all across Newfoundland.
Rick
I like the idea of the smaller window heaters. My partner and I also work at home in opposite ends of the house, and both have south facing windows. We could keep ourselves pretty toasty with these. Unfortunately, neither of us drink soda anymore, lol We’d have to get some cans donated. I like the idea too of using PC fans and power supply, that keeps the costs way down for building it. Thanks for the article!
The CanSolAir Heat Panel uses Lexan as its Glazing.
You could Blast it with a ShotGun and it wouldn’t Break.
This Panel is Rated as one of the Best in the World, by Mother Earth News (Autumn 2008).
The Panel Saves, on Average, the Equivalent of a Tank of Heating Oil per Season.
Get more info at cansolair.com
eMail: jim@cansolair.com
Phone: (709) 746 2077
Thanks.
Sounds good Lee. These things take a lot of cans so you help get the ball rolling by increasing your consumption of the canned beverage of your choice :-)
Rick
Very cool (or hot), let me know when you start building and I’ll come help!