Energy-efficient and money-saving LEED standards are definitely not just for new construction anymore. Retrofitted LEED-certified square footage now outstrips new construction.

There now is 15 million more square feet of LEED-certified space in existing buildings that have been revamped than in newly built buildings, according to numbers  from the U.S. Green Building Council’s (USGBC), the certification-granting organization for the Leadership In Energy and Environment Design program. 

The country has more than 60 billion square feet of commercial space that USGBC President and CEO Rick Fedrizzi characterized as "energy guzzlers and water sieves."

"Greening these buildings takes hands-on work, creating precious jobs, especially for construction workers. Making these existing buildings energy and water efficient has an enormous positive impact on the building's cost of operations," Fedrizzi said.

Among the buildings that have met LEED standards under the LEED: Operations & Maintenance guidelines are the Empire State Building and San Francisco's Transamerica Pyramid, USGBC said.