It is the tallest and almost certainly the best-known building in the U.S. to receive the award, according to Jones Lang LaSalle, the company that managed the retrofit.
Johnson Controls and Jones Lang LaSalle conducted the retrofit, and say the $20 million project is guaranteed to reduce the building’s energy consumption by more than 38 percent and should save $4.4 million in energy costs annually. The improvements also reduce carbon emissions by an estimated 105,000 metric tons over 15 years.
In January 2011, the Empire State Building Company agreed to buy wind-based carbon offsets totaling 55 million kWh per year from Green Mountain Energy, making the Empire State Building carbon-neutral.
In March, the window technology used in the retrofitting of the building went on sale for commercial use. The iWindow is a thin material frame which is installed on the inside of existing windows. This then improves the thermal performance of single pane aluminum systems.
iWindow manufacturer Serious Energy changed its name from Serious Materials in June.