Gary Reysa is a retired airplane product development engineer who lives in the "Big Sky" country near Bozeman Montana. His website Build it Solar has plans, tools, and information to help you build solar projects that save money and reduce pollution. Projects are low cost designs for the do it you selfer. Some of the projects featured on the home page are for a thermal storage wall, building a sun space, plans for passive solar homes, how he is coming on a plan to cut his own energy consumption in half, ten energy saving projects with one year paybacks and a solar space heater.
The simple and inexpensive passive solar space heater that he uses to heat his shop/barn is a project that could be completed in a weekend. The design can be adapted to suit a wide variety of spaces, including a living space.
He has published plans on how to build your own solar space heater system in a six page pdf from Home Power Magazine. Complete plans and instructions include detailed information about how the system operates, how it performs and what costs are involved.
The total cost for the 150 sq ft collector is about $350, and all the materials are available at your local hardware/lumber store. Materials are clear polycarbonate panels, black window screen (for the absorber), 2 x 6's, a couple of 2 x 8's, some 1 x 1's, "wiggle strips," caulking and hardware.
With current energy prices it has a payback of less than a year. The project could be made more aesthetic by using more expensive materials or even cost less if built into a house during construction. A smaller collector might be more appropriate for well insulated buildings.
Thanks to the tip from Alternative Energy News.