Millions of Americans looking to buy a home have a new resource to help them go solar in the process. Thanks to a partnership between Solar Energy Technologies Office (SETO) awardee Sun Number and real estate company Zillow, homeowners and prospective buyers across the country can now quickly and easily access detailed information about a property’s solar energy potential.

The Sun Number Score, developed through SETO's successful Incubator program, instantly determines a home’s suitability for solar by giving it a score from 1 to 100. The scores are an easy and intuitive way for consumers to understand their solar potential—the higher the Sun Number Score, the more ideal a home is for solar. The Sun Number Score technology uses a detailed roof analysis to determine how much roof area is suitable for solar based on the pitch, orientation, and size of each roof plane, as well as the amount of sunlight the roof receives based on surrounding obstructions like trees or taller buildings. Other factors that impact the score include the local cost of electricity, the local cost of solar, and local climate and weather conditions.

In August 2016, Zillow listed 35 million Sun Number Scores and the meaning of the score alongside other essential home facts such as the lot size, the year the home was built, and cost per square foot. There’s a question mark icon next to the Sun Number so curious customers can learn more about the components of the home’s score. Users can follow another link to a site that offers educational information about solar and a free preliminary solar system design for a home.

This prominent feature on Zillow’s home fact sheet gives millions of Americans access to information about solar for the first time. It primes new homeowners to think about solar potential in an easy-to-understand way and gives them access to resources that can help them make the switch to solar. This new level of awareness indicates the increasing importance of energy efficiency and consumer electricity choice in home buying, while providing an easy-to-understand assessment of solar potential for consumers who are unfamiliar with their home’s solar generation potential.

Sun Number Scores are available for 84 million American homes on Zillow, and over 110 million buildings in the United States have been scored on Sun Number’s website. In 2019, Sun Number was acquired by Solar Investments Inc. Learn more about the SETO's technology to market program and the intersection of solar and real estate