Which U.S. cities have most Energy Star buildings?

• Los Angeles is U.S. city with the most Energy Star buildings
• Among top 10%2C Phoenix and New York move up the most
• Half of top 10 are located in the South and Midwest

While Los Angeles remains the U.S. city with the most Energy Star buildings, the other top nine show marked -- perhaps surprising -- political and geographic diversity.

For the fifth consecutive year, Los Angeles held on to first place with 528 such commercial buildings last year, according to a 2012 ranking released Tuesday by the U.S. Environmental Protection Agency. One reason for its success is a state-wide policy that requires buildings disclose their energy use, says EPA's Jean Lupinacci.

Washington, D.C., where the federal government encourages green construction and retrofits, placed second for the fourth consecutive year with 462 buildings earning the energy-efficiency seal.

The other top metro areas, in descending order, include Chicago (353 buildings), New York (325), Atlanta (304), San Francisco (291), Houston (241), Dallas Fort-Worth (214), Phoenix (202) and Boston (188.) Among the top 10, Phoenix has shown the most improvement, moving from 22nd place in 2008 to ninth last year. New York, which recently required its commercial buildings to disclose their energy use, moved up from 12th in 2008.

"With Energy Star, cities across America are helping achieve President Obama's goal to cut in half the energy wasted by our businesses over the next 20 years," EPA Acting Administrator Bob Perciasepe said in announcing the list. Launched in 1992, Energy Star doesn't certify just appliances. lighting and equipment but also homes (now 1. 8 million) and commercial buildings (now more than 20,000.)

Since commercial buildings account for 17% of the nation's greenhouse gas emissions, EPA says improving their efficiency has huge economic and climate change benefits. Last year, it says Energy Star-certified buildings helped save more than $2.7 billion in annual utility bills and prevented greenhouse gas emissions equal to that of more than 2 million homes.

To earn the Energy Star seal, commercial buildings (stores, offices, schools) must perform in the top 25% of similar buildings, as verified by a professional engineer or registered architect. They use an average of 35% less energy and emit 35% fewer greenhouse gas emissions than average buildings.

The number of certified buildings continues to increase, jumping more than 24% between 2011 and 2012. Last year alone, more than 8,200 buildings earned the EPA seal.