Most of us think of SUVs as the No. 1 energy hogs, but they represent only 3% of North American CO2 emissions, while 38% is from buildings. And when you add the embedded energy of materials (8%) the figure jumps to 46%. Buildings account for 72% of electricity use, 39% of energy use and 14% of water consumption.

Our built environment is a huge opportunity for energy efficiency improvement.