Enlarge By Robert Deutsch, USA TODAY Jakob Kozcinski cleans the glass of one of the 6,514 Empire State Building windows before film is applied between layers to make it more energy-efficient. NEW YORK  You want to ask him: How many do you break? That's because Anthony Concepcion does windows — lots of windows. He's working at the Empire State Building. As part of an effort to become certifiably green, the office tower is removing, retrofitting and replacing each of its 6,514 double-hung, dual-pane windows. That's 26,056 panes of glass. PHOTOS: Empire State Building goes green "It's a lot of glass," says Concepcion, 39, work crew supervisor for the contractor, Serious Materials of Sunnyvale, Calif. "It's all part of going green." The building, for four decades the world's tallest and still the tallest in New York, is spending $13 million on windows, insulation and other upgrades to cut energy use by 38% and save about $4.4 million a year. Never has a structure so old and so tall gone so green. "It's the most recognizable building energy retrofit in the world," says Arah Schuur, director of a conservation program at former president Bill Clinton's foundation If you can retrofit the Empire State Building, you can retrofit anything, says Kevin Surace, president of Serious Materials. The building has earned a score of 90 (out of 100) from the Environmental Protection Agency's "Energy Star" program. That means a building constructed at a size (102 stories), a time (1930) and a pace (about 14 months) not known for energy efficiency now ranks in the top 10th of commercial office buildings. Tony Malkin heads the company that runs the tower. He says the goal, in addition to cutting costs and making the building more attractive to green-minded tenants, is to give other office building owners a model. The Clinton Climate Initiative, created by the former president's foundation, says buildings can account for three-quarters of greenhouse gas emissions in urban areas. But, Malkin says, "we're not talking about 'doing the right thing.' … Extra energy efficiency makes you money." The Empire State Building project has aroused interest among other high-rise owners, Schuur says, "but nothing far enough along to mention." Malkin says projects like his soon will be announced. Ahead of Chicago tower A year ago, the Willis (formerly Sears) Tower in Chicago announced plans to replace its 16,000 single-pane windows and put solar panels, windmills and gardens on the roof, all to help reduce electricity use by a whopping 80%. Kate Murphy, spokeswoman for the building, says finances have pushed back the project. Malkin, whose Empire State Building energy retrofit is about half finished, is dismissive of his rival in conservation, saying, "It's important to distinguish announcements from actions." The new windows, which have 2.5 to four times more insulation, are not really new. They are fashioned mostly from existing components by Concepcion's crew of 35. Working in two shifts, the crew assembles 75 to 80 windows a day in a noisy workroom on the fifth floor. Each night, workers remove scores of windows from their frames on the building's office floors. They wheel them to the workroom, where the glass panes are detached from their sashes, pulled apart and carefully cleaned. A sheath of transparent insulation film is laid between the panes, which are resealed and placed for an hour in a 205-degree oven to shrink the film in place. Next, a mixture of inert gases is pumped into the space between the panes for insulation. Finally, the panes are put back in the original sashes and remounted in the office floor frames from which they were removed the previous night. Surace, the Serious president, says he's never heard of a big building choosing to reuse, rather than replace, so much window glass — 96%. Malkin says he's saving about $2,300 per window and avoiding the environmental impact of trucking new windows from the factory and old ones to recycling. Changes go unnoticed Because the windows are removed after office hours and installed before most office workers return the next morning, one of the most ambitious projects in Empire State Building history is occurring without the knowledge of most of its occupants. The morning after the 32nd-floor offices of Skanska USA, a unit of the Swedish construction giant, had its windows swapped, "people didn't have a clue anything had been changed," says Deborah Ippolito, a senior manager. "You couldn't tell by looking at them." Skanska, which occupies the entire floor, is the kind of big, environmentally conscious tenant Malkin wants to attract with the energy retrofit and an overall $550 million renovation. Famous as it is, the Empire State Building never has enjoyed real cachet as a business address. Tenancy was so low during its early Depression years that it was derided as the "Empty State Building" and supported largely by visitors' observatory fees. Ever since World War II, it's had relatively small tenants paying relatively small rents. Malkin wants to rent larger blocks of space to more prestigious tenants at higher rents. A study by CoStar Group found that in the first quarter of 2009, green-certified buildings had fewer vacancies than other comparable buildings and that such buildings have commanded higher rents for several years. Green windows — actually, the sashes and frames are all painted the same city-landmarked shade of red — are part of that strategy at the Empire State Building. Which leads back to Anthony Concepcion and the issue of breakage. Normally jovial, he grimaces a bit at the question. "Some days, none. Other times, up to three," he says. "It averages out to about one a day." Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more