Google Fiber isn't the only next-generation technology from the Silicon Valley titan expanding across the United States this week.

The Internet giant announced on Thursday that it is also widening the net for Project Sunroof, an energy savings initiative that debuted in August.

Project Sunroof builds upon the aerial images in Google Earth to hone in and estimate a given home's solar energy savings potential.

Unveiled amid testing in just a trio of areas (San Francisco Bay Area, Fresno, Calif. and Boston) a few months ago, homeowners were instructed to enter addresses, after which Sunroof would respond with the estimate based on a variety of factors. These factors included (but were not limited to) local weather patterns, tree shade, and average electric bills.

The venture was the brainchild of engineering lead Carl Elkin, who designed Project Sunroof as the result of Google's "20 percent time" offering, an initiative encouraging employees to dedicate a fifth of their time to side projects. (Some of the more famous tools said to have been produced through 20 percent time include Gmail and Adsense.)

"Solar installations today are growing rapidly (a system is installed every 2.5 minutes in the U.S.), but there remains tremendous untapped potential. In fact, only half a percent of U.S. electricity comes from solar power," Elkin followed up in a blog post this week.

Thus, Google is now expanding the test pool to select metro areas across California, Massachusetts, Arizona, New York, New Jersey, Nevada, Connecticut, Colorado and North Carolina.

Interested homeowners can continue to enter their addresses in order to discover if their houses fall within the next level of the pilot program.