According to Lawrence Livermore Labs 36% of the country’s energy use is attributable to buildings and two thirds of that is in the residential sector.
This research combines building energy modeling with energy consumption data in transportation and infrastructure sectors to examine energy use implications of habitation patterns.
We compared CO2 footprints of three different patterns of typical American habitation: post-Second World War non-urban, 19th century urban, and highly urban. From drawings, utility bills, and occupant data, we used TREAT (Targeted Retrofit Energy Analysis Tool) to model the energy use of three buildings of very different constructions, comparing in the process the impact on energy use of envelope and size.
Because buildings don’t exist as isolated energy-using entities, we added the CO2 footprint contributions of location/density, reflected by infrastructure: numbers of miles of paving required to place a building in the landscape, miles of pipe for water and waste and the energy required by pumps to make it work.
Finally, people move between buildings, so we added a transportation component to account for occupants’ daily travel. Since buildings don’t use energy (people do) we divided total CO2 footprints by number of occupants for per capita CO2.
The final analysis quantifies the impact on an individual’s CO2 production of habitation (dense urban, historic urban, or non-urban) and how much impact energy conservation measures can have once the selection of a dwelling location is made.
Our analyses demonstrate that reduction of building energy use through improved construction affects only a small percentage of total energy usage.
Instead, choice of where to live determines individual CO2 footprints far more than building-related components. We found nearly a threefold difference in individual energy consumption from a New York City apartment dweller to a “close-in” suburban ranch house occupant with only minor differences between building-associated energy use. The bulk of the difference is attributable to differences in transportation utilization and infrastructure-related energy consumption.
Even as technical and legislative advances continue, our work demonstrates a broader societal dialogue about fundamental big picture issues, including sustainable densities, is critical.