DIY Solar Air Heaters – What will they think of next?

So there’s this new technology out, perhaps you’ve heard of it. People are using this technology to cook with, grow their own plants, create electricity, heat their water and heat their homes. Apparently, I’ve been living under a rock because it’s been around for some time. The sun can, amazingly, do all these things and more and I never knew. Well for those of you who are as troglodytic as I am, here is a pretty simple and cost effective and best of all cheap solar air heater that actually works (and its less controversial than Solyndra!)

Anyway, the sun can heat things up, not really a breakthrough of any kind. However, since there has been such a drive for green-this and energy efficient-that, I thought it was high time to discuss building a solar air heater out of crap you (or your neighbor) has laying around. And the best part is that you don’t even have to be very handy to build one. Of course, if you want your solar air heater to look good, an element of skill helps.

The frame can be made of a number of different materials, including 1″x1″s, 3/4″ plywood, heck my coworker built one using 1″ foam insulation board and just caulked it all together. Classy! The dimensions will vary depending on your use and the location you plan to put it. The key features of the solar air heater are important though. You’ll have an inflow section for air to enter followed by a chamber which is generally made up of several different rows of material to maximize surface area, followed by an outflow chamber that leads into the home. A sheet of clear plexiglass, glass or other plastic is used to intensify the sun’s rays. After that, the set up can vary to fit just about any design you have in mind. The inflow can come out of the home and cycle through, or you can build a window solar heater that draws air from the outside, heats it up and blows it into the house.

The inside chamber can be made of a number of materials as well. Gutters, soda cans caulked together, black storm drain pipe, even aluminum screen stapled to the frame. The key is to have something that absorbs heat and holds it well. Also, scientifically speaking, the more air pockets/surface area in the inside chamber the more thermal energy that can be collected. Then spray paint it flat black, which will absorb the heat the most.

You can also make this as technical as you want. The guy I work with hooked up a solar panel to a battery which operated the fan inside to push the air out. And to make things even more complicated he added a basic thermostat to kick the fan on and off at desired temperatures. This way he wouldn’t be blowing in cold air at night.

Finally, all you need is a good place facing south to collect as much of the sun’s rays as possible. And how well do these work? The solar heater I saw firsthand heated up to an internal temperature of 200 degrees F in about 10 minutes. Once the fan started blowing air out though it did cool to only 180 degrees, meanwhile the outside air temperature was about 67 that day. Not too bad. There are actually a lot of different plans and even some fantastic videos out there like the one below.  If you do try to make your own solar air heater good luck and happy building. Be sure to let us know you make out in the comments below.