SL Green Realty Corp. is under the process of replacing more than 16,000 antiquated lighting units with LED lighting in 21 of its New York City properties.

According to the company, lighting comprises 30 percent of a building's typical energy use. LED lighting reduces energy use by more than 55 percent. As a result, it expects LEDs will save the company more than $630,000 in annual energy use.

Date back to March 2012, SL Green installed 7,500 LED units within sixteen suburban division (Reckson) buildings, totaling more than 2.5 million square feet in its Westchester & Fairfield County portfolios.

In July 2012, SL Green will begin the next phase of its LED program to retrofit 4.5 million square feet in its NYC portfolio, including 420 Lexington Avenue, 100 Church Street, 919 Third Avenue and 125 Park Avenue. This project is anticipated to be completed in August 2012.