Purchasing new hardware? Read our latest product comparisons

Chicago’s Willis Tower to get solar windows


March 22, 2011

The south side of the 56th floor of the Willis Tower is being fitted with solar windows (Image: Harshil.Shah via flickr)

The south side of the 56th floor of the Willis Tower is being fitted with solar windows (Image: Harshil.Shah via flickr)

Chicago's Willis Tower, formerly known as Sears Tower, was the world's tallest building from 1974 to 1998 and remains the tallest building in the U.S. to this day. Its 1451-foot (442 m) height adds up to enough window area to keep a window washer busy for life, or space for enough solar panels to be comparable to a 10 acre solar power plant. As part of a pilot project, the south facing windows of the 56th floor of the Willis Tower will be replaced with Pythagoras Solar's transparent solar windows which cut down on heat gain – and therefore cooling costs – as well as harnessing energy from the sun.

While the image that comes to mind when one thinks of solar power plants is probably one of rows upon rows of panels covering large areas of desert, replacing the windows of skyscrapers with solar windows gives cities with limited free space the opportunity to create vertical solar power plants. Pythagorus Solar's solar windows, which the company calls photovoltaic glass units (PGUs), are rectangular box-shaped units that allow diffused light to pass through, but use a prism to reflect sunlight down onto a horizontal PV cell along the bottom of the unit to generate the same amount of energy as standard rooftop-mounted solar cells.

"We are excited to launch this pilot with Pythagoras Solar's leading-edge solar window solutions as a test for not only the energy savings that can be achieved, but the potential they represent to actually generate power through the sun," said John Huston, Executive Vice President of American Landmark Properties, one of the ownership partners of Willis Tower.

If the pilot project proves successful, Pythagoras Solar's PGU's could be expanded beyond the 56th floor to cover enough surface area to provide over two megawatts of solar power.

Via inhabitat

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

I think the CN tower qualifies as a building at 2717 feet, if so it is much taller than the Sears/Willis tower at 1451 feet, it can claim however to have been the the tallest \"office building\" in the world.

Carl van Bolderen

This is really cool! I have been waiting for a long time to hear of a building doing this. I hope it works as expected(and even better) so more buildings will follow suit!

Vickie Cyr

Why was the name of the building changed?

Facebook User

CN Tower is not a building. Between the ground and the observation pods high up, there are no floors. It\'s not much different from the Eiffel Tower, which obviously is not a building, either.

The name was changed because Sears sold and left the building. Naming rights can earn a lot of money for the current owners.


to the facebook user why Bruce Willis of course

Bill Bennett

i have been thinking along the same line but it wasn\'t feasible back in the 80\'s as solar panels were too expansive. japan could use these.

Jyanzi Kong
Post a Comment

Login with your Gizmag account:

Related Articles
Looking for something? Search our articles