How effective is wood as a thermal storage mass in a passive solar home or addition?
Being a typical construction material, wood can make up a significant portion of the physical structure of a home-and can contribute to the overall thermal mass. Strictly for storing heat, though, wood is less effective than more dense materials such as concrete, brick or water,” said Bruce Snead, residential energy specialist at Kansas State University. “The performance of wood as thermal storage will vary according to its density, thickness, and exposure to sunlight. Hardwoods like oak require 10 to 20 percent less exposed surface area than pine or other softwoods. When compared with an area of concrete four inches thick, wood at the same thickness requires three times more exposed surface area to store the same amount of heat. At a one-inch thickness of both materials, you will need 1.33 times more surface area of wood,” he said. According to Snead, wood in direct sunlight is 1.75 times more effective than the same thickness receiving only reflected sunlight, and 2.5 times more effe
