In 2009, the Empire State Building rebuilt 6,500 windows on site rather than replacing them, cutting energy use by 38% and paying for itself in three years

The Empire State Building underwent a significant renovation focusing on its windows. This project involved rebuilding existing windows instead of replacing them entirely. The initiative successfully reduced the building's energy consumption by thirty-eight percent. This resulted in annual savings of up to four point four million dollars. The successful retrofit demonstrated the benefits of repair over replacement.