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. The Chicago metro earned the No. 6 spot nationally for most Energy Star-certified buildings in 2013 with 233 properties, the EPA announced today.

Above us: LA, DC, Atlanta, NY, and San Fran. (But we’re coming for you, coastal cities. Once we finish our farm-to-table hot dog.) More than 23,000 buildings nationally earned the EPA’s Energy Star certification in 2013, saving $3.1B on utility bills and preventing greenhouse gas emissions equal to 3.3M vehicles. Michigan Plaza (205|225 N Michigan Ave) has earned the designation for the past few years (as well as LEED Gold), and MB Real Estate GM Steve Hennessy tells us the cost savings on operating expenses is passed right on to the tenant. (Energy Star office buildings cost $0.50 cents less/SF to operate than average office buildings.)

Energy Star establishes minimum baseline for LEED certification, and buildings will make operational improvements from there to boost sustainability, Steve says. (Michigan Plaza is 95% complete in updating its fan systems). Prospective tenants consider a number of variables when picking a building, but Steve believes a more efficient and environmentally friendly building will always have an advantage. And a city ordinance to have buildings send in their Energy Star scores and energy use stats, to be made public, should boost participation in these programs, Steve predicts. (Nobody wants to be at the bottom of that list, or picked last in dodgeball.)  Will it lead to green-driven rent hikes? It would be nice, but too early to tell.