I have been working on this solar kiln off and on all summer. So today I moved it outside the shop and wired up the fans and thermostat. It is pretty much done now and ready to dry lumber. The inspiration came from Virginia Tech's design which I modified and adapted to my own needs and taste. The walls and floor are totally insulated with fiberglass insulation. The doors have an inch and a half of styrofoam sandwiched between the the siding and the inside sheeting. There is a layer of plastic covering the fiberglass insulation before the inside sheeting was installed. The sheeting is 7/16 osb painted with aluminum fiber roof coat paint and then painted flat exterior black. The roof is poly carbonate sheeting. I'm not sure if they will hold up or not but I am using window box fans for circulation. The 4 fans will pull in cool air from the top vents and will blow across the top of the lumber stack, down the front of the pile, thru the lumber stack and then exit out the bottom row of vents. There will be a tarp baffle installed just under the fans that go down to the lumber stack so that the air can't go straight down and out the bottom vents without going thru the lumber to be dried. Winter is not the best time to use a solar kiln but I'll try and see what it can do. At least I will be ready to go in the spring! This is my first experience using a solar kiln but I am pretty optimistic about it. I ran into a guy the other day that has a solar kiln and he had it facing west instead of south (because that is where it fit in front of his shop) and he just had a little solar fan circulating air inside with no circulation to bring in cool air and exhaust hot moist air. He thought it worked pretty good and was drying about 3 batches of wood during the summer. So I figured that if his works that good, mine should work a lot better. Thanks for looking!