The $20 million project is expected to save the building's owners $4.4 million annually in energy costs, and will reduce its carbon dioxide emissions by 105,000 metric tons during the next 15 years — equal to the annual emissions of 17,500 cars.
Former President Bill Clinton and New York Mayor Michael Bloomberg both attended the announcement on the Empire State Building's 80th floor Monday and said they hope the environmental changes at the iconic skyscraper will serve as a model for buildings around the world.
Clinton, whose foundation is helping with the environmental upgrades, said the only way to get property owners worldwide to make over their buildings is by setting an attention-getting example.
"We have to prove it's good economics, and we have to prove we know how to do it," he said. "Every person on Earth who cares about this knows about the Empire State Building."
Experts say retrofitting old buildings — which rises 1,453 feet (443 meters) — to be more environmentally friendly is an important step in reducing levels of heat-trapping greenhouse gases. In New York City, emissions generated by the operation of the more than 900,000 buildings citywide contribute 79 percent of the city's total.
The upgrades planned for the Empire State Building include replacing all of the skyscraper's 6,500 windows with a type of insulated glass that reduces summer heat load and winter heat loss.
Extra insulation will be installed behind radiators to save heat. Other changes are planned for the building's ventilation, chilled water and lighting systems.
Work already has begun, with the upgrades to the building systems expected to be completed by the end of 2010 — longer than it took to build the skyscraper, which opened in 1931 after a year and 45 days of work.
All of the building's green projects are expected to be finished by the end of 2013.
Bloomberg, who has set a goal to reduce the city's carbon footprint by 30 percent by 2030, said the famous landmark shows "the rest of the city that existing buildings, no matter how tall they are, no matter how old they are, can take steps to reduce their energy consumption."