Throughout the history of architecture, energy efficiency, and CO2 emissions were considered marginal issues until the late 20th century. The low scores of some iconic modernist buildings in the Energy Star certification program illustrate this situation. The MetLife/PanAm Building (designed by Walter Gropius and Pietro Belluschi in 1963) received a dismal score of 39 (on a scale of 0 to 100), while the Lever House (designed by Skidmore, Owings & Merrill in 1952) scored 20. The worst performance was by Mies Van der Rohe's iconic Seagram Building, constructed in 1958, which received only 3 points. On the other hand, two revered Art Deco buildings from the 1930s, the Chrysler Building and the Empire State Building achieved scores of 84 and 80, respectively, as a result of extensive upgrades to their mechanical and insulation systems.
