Curious about solar? This Saturday you can take a free tour of homes that have added solar installations.

The 16th annual National Solar Tour sponsored by the American Solar Energy Society (ASES) is billed as the largest grassroots solar event and features a local look at homes that use solar panels as well as other energy efficiency technologies and green innovations.

ASES partners with dozens of local organizations in several locations from Maine to California. It’s held in October — Oct. 1 this year — to coincide with National Energy Awareness Month and is expected to draw more than 165,000 participants to see more than 5,000 buildings across the United States.

Find open houses in your area use the ASES map showing tour locations.