Inexpensive Solar supplemental heating system
New whole-house solar heating systems initially cost $14,000 or more. In contrast, a conventional heating system might cost $6,000 to $13,000 for the same size house. The cost fluctuates depending on the size, type of house, location of house and amount of solar fraction available. If you have an existing radiant/space heating system you can reduce the cost of your new system by adapting any solar radiant/space heating kit such as SunMaxx HH-1000/1500/2000/2500 from the Silicon Solar to your existing system. And by adding an Air-to-Water heat exchanger you can integrate your new kit even into your existing forced hot air system! For a house of 1000 square feet an installed SunMaxx HH-1000 kit will cost you from $12,000. This kit designed to assist in offsetting approximately 192 gallons of heating oil annually, because it contains two very efficient SunMaxx-30 solar collectors. But I think it's very logical to spend much less amount of money to see how solar heating really works in your specific area.
I used 2" x 4" pine boards and 5/8" plywood to build the solar collector frame/box. Then, I painted the whole unit. The frame size is 36" x 79.5"
For my thermosiphon heating system I used 2" x 6" pine boards
All frame seams were sealed.
I also used a one-inch insulation board with aluminum foil (back side). It works not only as an insulator, but also as a heat reflector. You can use high density (rigid) polyisocyanurate foam - melting point is 177 degrees Celsius or expanded polystyrene - melting point is 240 degrees Celsius.
Insulation board installed.
The seams of the insulation board were also sealed.
For my collectors with 2" x 6" boards I used Super TUFF-R(TM) C 2.00 inch commercial insulation sheathing (modified polyisocyanurate rigid cellular polymer) Manufacturer - DOW Melting Point >150 C/302 F R-Value - 13.0