Last week’s conference in St. Paul featured a presentation by Mike Jackson of the Illinois Historic Preservation. Among preservationists, Mike is known as an Energy Guru on the subject of the energy embodied in historic buildings, and on the operational efficiency of historic buildings. During his presentation, Mike referenced a recent article by BuildingGreen.com that found that commuting by office workers can account for far more energy use than building operations. According to BuildingGreen calculations, commuting “accounts for 30% more energy than the building itself uses.” As building efficiency goes up, the proportion of energy used for transportation is even more significant. “For an average new office building built to code, transportation accounts for more than twice as much energy use as building operation.”
So what does the mean? While new green buildings – such as those certified under the U.S. Green Building Council’s LEED standards -- may be energy efficient, the context in which they are located isn’t necessarily sustainable. I’m reminded of an excellent piece I ran across recently in Greener Buildings in which Shari Shapiro discusses "green sprawl," -- development in which green buildings are located in unsustainable contexts. Under most green building standards, buildings are certified as “green” because they incorporate energy efficient features, provide adequate daylighting, – and meet a host of other criteria. While these standards may encourage development in existing urban areas, they do not require it.
I’ve done a bit of research that seems to substantiate concerns about “green sprawl.” About 19% of LEED-NC (New Construction) projects have earned a credit for being located in a densely developed area – that means 81% of LEED-NC certified buildings don’t meet the USGBC’s requirement for dense development. Though a relatively small number of historic buildings have been LEED certified (about 35 out of more than 400), more than 50% of historic projects have earned the credit for dense development. Furthermore, over 90% of LEED-NC certified historic projects earned a credit for providing access to mass transit, as compared to about 60% of newly constructed projects.
The research bears out expectations that many historic buildings are located in sustainable contexts – and location matters. Rehabbing and re-using these buildings allows us to capitalize on existing infrastructure – including mass transit -- reducing those gas guzzling commutes.