Location: Ashburnham, Massachusetts

Watts: 5,100

Monthly Production: 425 kWh

Date: August 2015

Electricity savings with solar really add up. This relatively small system (by today’s standards) should produce nearly $22,000 worth of free electricity over the first 20 years. The grandstand-mounted system, which has 20 Canadian Solar 255-watt panels and SolarEdge inverter technology, was turned on in August 2015.