I had some old glass that I used to make a solar air heater. The downspouts cost about $9 a piece so with tax about $40 for 4 tubes cut in half. The AC insulated vent tubing to run from house to the heater cost $27 for 25 feet. The rest of the wood I had on hand. I used 3/8" OSB and its ok but not for the baffle section...I should have used plywood..but it will be just fine like this. I cracked the glass when it was in the sun for a while and then I turned on the fan to test it. The cold air blast caused the crack. It should never happen again since the fan comes on while it is just starting to heat up now. I used an old 12 volt computer fan for air circulation. I added two cutoff tubes at top and bottom to add a bit more heat. The thermal images at the end show first, two pictures of temperature in open air with no glass on it yet. Next two are of first warm-up at 9:30 am with outside temp of 60 degrees. The first is out going from the house, then the input to house from heater after fan started running. The next picture is at input from heater, about 10AM and 62 degrees outside. Then at 11am nd 64 outside temp. The last one is from about 12:30 and 67 degrees outside temp. It really blows some ice hot air, and a nice breeze too. It IS VERY worth making one of these !!!