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Do You Know What’s Really In Your Products?
Allison Ewing / ECOHOME / August 29, 2013
If we are to become carbon neutral, we need consider not only the energy performance of a home or structure, but also the embodied energy of the materials that go into construction of the dwelling—the cumulative embodied energy. The average home has 300 mWh hours of embodied energy, roughly 25 percent of the total energy used over the lifetime of the building. While the operational usage outstrips the embodied energy in the long term, if we are to truly talk about net-zero energy, embodied energy needs to fit into the equation.
But how should we choose the best materials? Should we focus on renewable, recycled, low-maintenance, local, or a combination of all of these attributes? Embodied energy takes into account the total energy used throughout a material’s lifecycle—not only the energy used to extract the raw material, but also the energy used for the transportation involved along the production chain, processing and manufacturing, construction, and maintenance over the years, as well as disposal and recycling. The full path is often called “Cradle to Grave.”
It can be complicated. While the embodied energy of one recycled product might look promising, when you consider that material might travel from a factory in China to a construction site in the U.S, the embodied energy literally becomes a moving target. In an effort to disentangle these complex issues, we at Hays Ewing initiated a materials mapping project, called SpecLocal.
We decided to initially focus on mapping bio-based materials in the United States. Bio-composites are either plant-derived fibers, or crop-derived plastics. Our idea was to build a database of bio-based construction materials that will eventually be available to the construction industry. The goal is to increase the market accessibility of locally extracted and produced materials, while helping to expand manufacturing jobs in rural America. An embodied energy calculator will also be incorporated in the database to assist the user in determining the energy inputs for transportation.