www.sulltek.com This is a video of the Passive Solar Heating System in use at http in Whitby, Ontario, Canada. It provides a great deal of heat, and the installer, Chris, will be making it more effecient by adding a second computer fan to push the warm air at the top, painting the inside better and taping the duct work. Also, the duct work will be directed into the office where the door can be closed and used in a smaller air mass. This kind of heater is ideal for urban survival and bugging in, since it requires no power input and is cheap and easy to make. It’s not just for strawbale, cob, cabins, cottages, earth ships or businesses. They can be installed on a home, and they look great when done right. Ragnar Benson would be proud. Visit our site at envirosponsible.com or call us at 905-666-2002.