How Energy Efficient Are Modern Buildings?

As part of the U.S. pledge to decrease greenhouse gas emissions by 80% by 2050, New York City has made an effort to improve the energy efficiency of its public buildings. However, in 2012, energy audits found that some of the city's newer, so-called "green" buildings -- such as 7 World Trade Center, which opened in 2006 -- scored lower than some much older buildings, such as the Chrysler Building, which opened in 1930.

The 52-story skyscraper at 7 World Trade Center does hold an LEED Gold rating for environmentally-responsible design and management, but in the 2012 audit, the building received only a 74 rating based on the EPA’s Energy Star standards. A building must score at least 75 to be an Energy Star high-efficiency building. On the other hand, the Art Deco-style Chrysler Building scored an 84.

Energy efficiency, by the numbers:

• Older structures like the Chrysler Building tend to be better thermal envelopes, with thicker walls, fewer windows, and less ventilation.
• Not all older New York buildings scored well in 2012. The Seagram Building on Park Avenue earned a score of 3, mostly because of its single-pane glass curtain walls and fluorescent lights.
• The top 2% of New York City’s largest buildings account for 45% of the energy used by all city buildings.