The buildings are heated by a homemade solar hot air collection system. The collector is a sheet of black metal and a sheet of glass with a one inch air gap between them. The upper pipe collects hot air and blows it down through a duct that leads underneath the building’s floor. The duct has slots in it so that hot air escapes and heats the floor, which is made of course rock so air can flow through.
The key to LEF’s heating system is smart construction. The thick walls of the buildings are made of straw-bale, a strong material for insulation. The buildings also have large east-facing windows to allow for natural lighting and heat to enter in the morning.