As energy-efficient green building becomes mainstream, more and more home and building owners are adopting green remodeling as a way to build up energy efficiency without the cost of a new build. The Empire State Building in New York City is no exception.

By simply retro-fitting the windows on the structure, the firm that manages and owns the building expects to reduce energy consumption by 40% and save $4 million a year in bills.

Over the next 15 years, the building's carbon footprint will be so reduced it will be like taking 20,000 cars off the road. View more details about the retro-fit here.

For more details on how installing and replacing windows in your home could save you money, visit the ENERGY STAR website.