For example, it is not necessarily older structures that pose the biggest energy challenge.

Older buildings tend to have higher Energy Star scores because they have thicker walls, fewer windows and less ventilation — superior “thermal envelopes,” as a report on the early results puts it. They are also less suited to energy-gobbling activities like computer data crunching, the downfall of some youthful but middling performers.

“Some scores will not be flattering, but identifying buildings with the most opportunity to improve is a big part of driving energy savings,” said Andrew C. Burr, a performance expert at the Institute for Market Transformation, a Washington advocacy organization promoting energy efficiency, which advised New York City on analyzing the results. “It does put energy on the radar of real estate consumers.”

The stakes are considerable. Unlike cities that depend heavily on automobiles, New York racks up most of its carbon dioxide emissions — nearly 80 percent — in heating and cooling buildings. Tracking this energy use is deemed crucial to meeting the city goal of cutting overall emissions by about a third by 2030, to slash costs and fight climate change.

New York’s largest buildings — just 2 percent of the roughly one million buildings in the city — account for 45 percent of the energy expended by the entire building stock.

Owners of more than 2,500 nonresidential structures disclosed energy use this year, but there were truants that did not submit their 2011 data by the required deadlines and thus face fines of $2,000 a year. The disclosure law exempts buildings in which more than 10 percent of the space is devoted to trading floors, data centers and other energy-intensive activities.

Yet work spaces that hum 24/7 seem nonetheless to have played into the results, including 7 World Trade Center’s score.

“Seventy-four is good, but I was initially surprised that three of our older buildings scored higher than 7 World Trade Center, and it had to do principally with tenancy,” said John Lieber, who oversees buildings at ground zero for Silverstein Properties. He noted that 7 World Trade Center’s tenants included firms like Moody’s, the financial rating agency.