Like grass-fed, locally sourced, and cruelty-free have become de rigueur labels in dining, Energy Star remains the thing to namedrop when courting office tenants. LA, DC, Atlanta, NY, San Francisco, and Chicago toppeed the list for most Energy Star-certified buildings in 2013, the EPA announced last week. (More than 23,000 buildings nationally nabbed it, saving $3.1B on utility bills and preventing greenhouse gas emissions equal to 3.3 million vehicles.) Above, MB Real Estate GM Steve Hennessy—whose Michigan Plaza in Chicago has earned the designation for the past few years—says the cost savings on operating expenses is passed right on to the tenant. (The EPA reports Energy Star buildings cost $0.50 less/SF to operate than an average office building.) Prospective tenants consider many variables when picking a building, but Steve believes a more efficient and environmentally friendly building will always have an edge.