Clean energy meets green building

Imagine you’re sitting in a meeting in high-rise office building on a sunny afternoon.

As the meeting drags on the room starts to heat up, so you bump down the thermostat, pull the shades and turn on the overhead lights. You may be more comfortable, but you’re also consuming a lot more energy.

Pythagoras Solar says it has a solution to this very problem. The Bay Area startup makes solar windows – called Photovoltaic Glass Units, or PVGUs – that generate power while reducing energy consumption.

Specifically, Pythagoras’ windows, curtain wall windows and skylights, which are embedded with solar cells, cut down on solar heat gain inside buildings while producing about 13 watts of electricity per square foot. 

“We’re changing the energy equation,” Pythagoras marketing chief Udi Paret told Sustainable Industries. “The combination of [energy efficiency and power production] is what creates the economic value.” The company says the windows offer return on investment of three to five years. 

Pythagoras, which was a winner of GE’s Ecomagination Challenge, kicked off a pilot project late last year on the south-facing façade of the former Sears Tower in Chicago. Its products are available commercially in small quantities, but it’s ramping up to larger scale production and plans to announce a big commercial installation this summer, Paret said.

For now, it plans to target high rises and large commercial buildings with large areas of façade. The company’s skylights could also be used in large retail applications, Paret said.