William and I had the opportunity to listen in on a webinar provided by the Passive House Institute of the United States (PHIUS) on limiting embodied carbon in buildings: “Spaghetti Carbon-Era: Disentangling Operational and Embodied Carbon.” Admittedly, I just got the pun of the title…which is all the more humorous if you were to have seen their intro presenting page being that of pasta in a white sauce with bacon.
This seminar was very helpful in reiterating the importance of taking a holistically sustainable approach in home building and living. Not only should the home be environmentally friendly and energy efficient during its usage, but also in its construction and sourcing of materials. The ‘environmentally friendliness’ here is measured by the amount of carbon a home is responsible for emitting. PHIUS standards make a home accountable for its carbon footprint in its operation alone: as in, how much energy the home needs to function once it is already built. This they call “operational carbon” or, “OCO2e.” In the webinar, they expressed that the home has an even larger carbon footprint when its “embodied carbon” or, “ECO2e” is taken into account. Embodied carbon is the amount of carbon that is emitted in the overall construction of the home: from the harvesting, manufacturing, and transportation processes of all of the home’s required building materials. That pink fluffy fiberglass insulation and wooden studs and concrete foundation and drywall has to be made out of something and transported from somewhere…all of the materials have their own carbon footprints which then contribute to the home’s overall embodied carbon.
Two of the presenters, Ilka Cassidy and Steve Hessler, founded a business called “Holzraum System, LLC.” Within their business, they did their own study of how much of a home’s carbon footprint is operational and how much of it is embodied. They used five different homes as case studies.
Home One: built to meet 2009 building code
Home Two: built to meet 2009 building code with high performance systems
Home Three: built to meet Passive House standards, but with a high usage of foam
Home Four: built to meet Passive House standards, but with a low usage of foam
Home Five: built to meet Passive House standards, but with no foam.