Solar Air Heater Tools and Expenses
If you are considering building a solar air heater yourself you may be interested in the tools needed and the approximate budget for the air heater I have built for my house. I have described the construction of the heater in earlier posts which you can find here: Trial 1, Trial 2, Completed
solar air heater in winter
My research told me that a collector should be about 1/10th of the floor area you wish to heat and my main floor is 440 square feet so that is how I determined the size of the heater area. I also wanted to be sensitive to the integration of the heater into the house facade and that limited its size. The next time I build a solar air heater it will be bigger. Why not really? You can always get rid of excess heat but you can get more heat from an undersized collector. Anyway, I ended up building a 43 square foot collector and this post is about the tools and expenses needed to build a collector of this size.
I have listed the equipment and materials that I used for the project. You could easily complete the project without all of the equipment in the list but the materials are all pretty essential. The one area of variation in the materials section might be the absorber. Some studies I have seen of felt and screen absorbers show potential. Other than that element though you should really have everything on the list. You especially don’t want to skimp on the fan and solar panel because they will be driving the whole system. The upfront cost of this solar panel/ DC fan combo is high but will save energy and headaches in the future. The alternative would be to hook up a grid tied AC fan with a thermostat but an AC fan will use a lot more power and you’ll be paying for it. I guess you could also use an inverter to hook up a grid tied DC fan but again that is just more equipment, wiring and power you will be paying for. The simplicity and long term economics of the solar panel and DC fan are just too attractive to ignore I think.
Equipment:
tin snips
drill
skill saw
paint brush
staple gun
hand saw
(a jig saw or reciprocating saw would have been nice for the holes in the wall)
Materials:
bubble foil radiant barrier: $30
4 salvaged double pane windows: $80
aluminum flashing: $60
flat black high temp. spray paint: $20
aluminum tape: $10
12 inch DC fan: $150
25 watt solar panel: $200
Other: silicon, screws, stain, wood for frame, staples, wire: $50
Total: $540
That total is trivial compared to the cost of a well known commercial model like the Cansolair Solar Max 240 which retails for $2695. That purchase would also require taxes and shipping so the total is really more like $3000 to get the unit to your door. That collector only has an area of 28 square feet and mine covers an area of 43 square feet so a cost per square foot would be even more telling of the economy of building your own collector. A simple calculation reveals that my collector has a cost per square foot of $ 12.50 and the cost for the Solar Max 240 is around $100 per square foot! In an field where size is king and low tech possibilities are plentiful why not build a collector yourself for a tenth of the cost. Depending on your access to materials you may sacrifice a bit in terms of efficiency but that is a difference you can make up easily in collector size. In addition you will enjoy the pride that comes with doing the project yourself and can integrated the collector more appropriately into the design of your home.
Nice article and heater. You may want to consider solarwindowheaters.com for your next solar air heater. They have a great tech department and thier new solar air heater profiles make building soooOoo easy. Your fan cost way to much. Great job tho…. Oh take a look at their blog too.
Neat post, my first visit. I’m planning on building a home in the next few years and want to incorporate these types of ideas. But, I’d rather to myself. Thanks for the information.