Saving money with energy efficient windows. If the Empire State Building can do it, so can you.

With its upgraded windows, the Empire State Building is enjoying an annual energy savings of $338,508.

In 2009 New York’s Empire State Building showcased a new process to retrofit existing buildings to improve environmental sustainability. The goal of the $500 million upgrade program is to upgrade some of the tallest buildings in New York City to reduce energy usage by up to 38%. The process was also created with the intention of being used for similar projects around the world.

The program is being spearheaded by former President Bill Clinton’s Clinton Climate Initiative, as well as the Rocky Mountain Institute, Johnson Controls Inc. and Jones Lang LaSalle.

“In this distressed economic climate, there is a tremendous opportunity for cities and building owners to retrofit existing buildings to save money and save energy,” said Mr. Clinton today at the announcement. “I’m proud of the work my foundation’s climate initiative has done with 40 of the world’s largest cities, including New York.”

The buildings 6,500 existing double-hung windows were dismantled and rebuilt onsite to include a suspended coated film and gas fill. This more than tripled the insulating value of each window, increasing occupant comfort, blocking winter heat loss three-times better than the old windows, reducing heating and cooling loads, blocking ultraviolet rays to protect occupants and furnishings, and enhancing daylight.