Energy Savings - Wood is naturally a good insulator. A PWF basement, by having stud spaces already present, enable insulation of any kind to be quickly and economically installed between the studs. Unlike Poured Walls and Block basements, no additional furring needs to be added to accommodate the insulation. An R-21 wall is not uncommon for a Permanent Wood Foundation. Most of the energy loss in a building is through the basement walls when poured walls or block. This is because concrete and block are good conductors of heat. Ever notice green grass adjacent to some foundations in the middle of the winter but brown a foot away? This is because the soil surrounding the building is being heated by the foundation conducting heat through the wall. Energy is wasted. This will not happen with a Permanent Wood Foundation. This energy is saved. In addition a very subtle energy savings results just by using wood. The energy saved to manufacture lumber and plywood way exceeds the amount of energy required to manufacture concrete and block. We will never run out of our supply of wood. More wood is added by growth each year and far exceeds the amount harvested from forests. It is a very environmentally friendly product.