ENERGY EFFICIENCY

Sustainability of Building Materials 

WoodSteelConcrete
Total Energy UseLowest140% more70% more
Greenhouse GasesLowest45% more81% more
Air PollutionLowest42% more67% more
Water PollutionLowest1900% more90% more
Solid WasteLowest36% more96% more
Ecological Resource UseLowest16% more97% more

Source: The Athena Sustainable Materials Incentive

Wood surpasses steel and concrete in energy efficiency through its qualities of:

Thermal performance.Heat conductivity.Building codes.Insulation.

Thermal performance – The heating and cooling of homes accounts for 50% of all utility costs (gas, oil, hydro-electric) and about 15% of all energy used in North America. With rising energy costs and rolling blackouts across the country, energy efficiency is a critical factor in buying or building a new home. The energy demand difference between a poorly constructed and a well constructed, well insulated home can amount to several thousand dollars a year.

Wood’s heat conductivity – Wood is 400-times less heat conductive than steel and 8.5 times less conductive than concrete, so homes built with wood framing take less energy to heat and cool.

Steel’s heat conductivity – Like the fins on a radiator, sheet metal studs transfer large amounts of heat to the outside air during winter. They also transfer cold inside during summer. The movement of cold into a house through the framing is called thermal bridging. Thermal bridging increases energy consumption. To prevent this, steel framing requires extra insulation on the outside sheathing which can add significantly to building costs. The heat loss through steel framing can also result in lower temperatures where the steel contacts interior walls resulting in ghosting (paint discoloration).

Building codes – Wood construction can meet the energy codes of all climates. In extreme climates like Alaska and the Canadian Arctic, the adoption of double wood-frame wall systems keeps homeowners warm when temperatures drop in winter to -40ºF. New energy code requirements in several European countries have prompted a switch from traditional masonry construction to wood.

Insulation – Wood is energy efficient not only because it’s a good insulator, but its versatility makes it easy to adjust the width of a wall to accommodate extra insulation where necessary. Additionally, oriented strand board (OSB) or plywood wall sheathing, typically used under a home’s exterior finish, offers additional insulation and provides rigidity and security to a home. The insulated cavities in wood-frame construction, in combination with the superior insulating capability of wood framing means that wood can meet the most demanding energy codes with less cost.