Iowa Utilities Board, Office of the Consumer Advocate (Des Moines, Iowa: 2011)

There are apt metaphors to be made about this government office building, erected on the site of a former landfill, yet built in such a way that nearly 90 percent of construction waste was recycled. Designed by BNIM architects, the structure’s two wings were made from white Thermomass precast concrete, and gaps that might lower energy efficiency were meticulously removed. The result is a sleek profile that achieves a 75 percent reduction in energy usage compared to a similar code-compliant building.

Photo by BNIM  Photo 9 of 10 in 10 Green Commercial Buildings