If there ever was a beacon for green buildings and energy efficiency, it would no doubt be the green skyscraper. And if there was ever a skyscraper that served as a beacon for other skyscrapers, it would no doubt be the famous Sears Tower in Chicago, aka the tallest building in the Western Hemisphere. That said, now that the Sears Tower is set to undergo a green upgrade to to the tune of $350 million, it is undeniably on its way to become one of the most green skyscrapers in the world.

These days, there are a growing number of skyscrapers that deserve to be called "green skyscrapers". There's the Bahrain World Trade Center Towers, the Pearl Tower in China, Bank of America skyscraper in New York, the CIS Tower in Manchester, and let us not forget 340 on the Park in Chicago, which will likely become the first LEED certified residential green skyscraper in Chicago. The one thing that is common to all of these skyscrapers is the fact that they are either currently under construction or recently finished. But what about the longstanding skyscrapers that were built before the green boom?

Apparently, all it takes is a green refurbishment. As for the Sears Tower, it aims to reduce electricity usage by 80% and water consumption by 40% through the incorporation of several time-tested green building specifications, or in this case, LEED guidelines for green skyscrapers. Speaking of LEED, which stands for Leadership in Energy and Environmental Design, American Landmark Properties has also proposed building a LEED certified hotel adjacent to the looming skyscraper.

You're probably wondering what $350 million will do to help make the Sears Tower one of the most green skyscrapers in the world? Well, in terms of saving water, all of the restrooms will be refitted with fixtures designed to filter and save water (in the same fashion as a showerhead filter), while the entire building itself will be fitted for condensation recapture. Now that's what I call being resourceful. I'm not quite sure just how much condensation can and will be collected, but considering all the surface amount of the Sears Tower, you can bet it will amount to a few gallons of water. 24 million gallons to be exact, because that's how many gallons are expected to be conserved.

In terms of energy, the Sears Tower is aiming to set a benchmark which architect, Adrian Smith, says will help skyscrapers to drastically limit their impact on the environment. This will include replacing over 16,000 windows to create a "thermal break" between extremely hot and cold temperatures, installing gas boilers with fuel cells (generating heating and cooling along with electricity), harvesting daylight with the use of automatic light dimmers set to respond to varying natural light levels, using solar panels to heat water, and possibly installing wind turbines if needed. Furthermore, all of the escalators and elevators in the Sears Tower will be upgraded to help reduce electricity usage by 40%. And since this is Chicago we're talking about, the Sears Tower couldn't become a green skyscraper without a green roof.

Another big change for the Sears Tower will be it's name, albeit not a direct result of the green improvements. As part of a deal with new tenant, Willis Group Holdings, the 110-story building will be called the Willis Tower as of late Summer 2009. The building's owners, American Landmark Properties, should be credited with the massive haul over, which in the end, will end up saving millions of dollars in energy costs.