If your looking for a cheap way to gather the solar heat for fall, winter, and spring, heres something I think would be a good project, the idea is to cut a 55 gallon drum in half, the cardboard and wax ones would be best, you can get them free from newspaper companies free, their used for ink, and their easy and not toxic to clean out, get some 2x2s and attach them inside the top and bottom of the barrel halves, too extend the length of the barrel to 8 or more feet, on the back side of the collector, attach some heavy black roof felt paper to three of the 2x2s, 9:30, 12:00, and 2:30 positions, the front only needs one 2x2, at the center of the barrels, place a 6x6 inch furnace pipe with caps at the bottom and top, paint it black, remember to clean off the oil first, fill it with sand, then wrap the unit with some good plastic wrap or what have you, get uv protected plastic.
A pipe goes into the bottom from your lowest point of what you want to heat, and a pipe comes out of the top back into the building, at the lowest point hook up a small furnace squirrel fan blowing in, the thermostat would be located at the top of the barrel, a good cheap thermostat is here,
http://www.lmimg.com/OrderPage.asp?PN=LMITC21.
Almost forgot, the barrel halves don't have to be full halves, cut them long enough for you to screw the 2x2s to them and enough to wrap the plastic around, with the middle of the original barrel, cut this in two inch loops, that will be positioned up through the system strengthening the mainframe, remember also to have these loops on before you wrap with plastic.
