Growing up in the 1980s, Amy Cafazzo remembers her parents investigating what it would take to mount solar panels on their home’s roof to take a bite out of their energy bills. The expense was too great, so the plan fizzled out.

Fast forward to the present, and Amy and her husband, Mark, are a month and a half into generating most of their household electricity through 21 solar panels mounted on the garage attached to their Hopkinton home.