Mike Moore, owner of a new zero net energy home under construction in Evergreen, CO yodels inside a 2,000-gallon salvaged stainless steel tank that will soon serve as the home’s “thermal battery”. This tank will store heat in water for use during periods of cloudy, cold weather when the home cannot generate all of the heat that it needs through passive solar gain. Heat from the hot water in the tank is transferred to a coil that runs inside the home’s duct system, as air blows across the coil, heat is transferred to the air and distributed throughout the house.