More than 6,500 windows were upgraded as part of the Empire State Building’s recent retrofit and renovation. Now, the building has been awarded LEED Gold for Existing Buildings certification as further recognition from the $550 million Empire State ReBuilding program. According to the announcement, the retrofit conducted by Johnson Controls and Jones Lang LaSalle is guaranteed to reduce the building’s energy consumption by more than 38 percent and should save $4.4 million in energy costs annually, representing an approximate three-year payback of the cost of implementation.

As part of the renovation, the upgraded windows were supplied by Serious Materials. The company provided its SeriousGlass™ technology, which is created through a sustainable production process designed to directly reduce energy costs by more than $400,000 per year. The new units will increase the thermal performance of the windows by up to four times their current thermal performance and will also reduce solar heat gain by more than 50 percent compared to the older windows.

The building gained ENERGY STAR certification in 2010 and has maintained ENERGY STAR certification in 2011. In addition, the announcement notes that the improvements reduce carbon emissions by an estimated 105,000 metric tons over 15 years.