Boston Police report  they're investigating a possible scam involving a guy claiming to be from an outfit called Just Energy, going around the Newcastle Road area  in Brighton, knocking on doors and asking homeowners if they'd like an energy audit:
In one case, a community member states that an individual described as a black male in his thirties, 5’8” tall, holding a clipboard and wearing what appeared to be a uniform, possibly green in color, knocked on his door and offered to conduct an energy audit. When the suspect asked to see the victim’s energy bill, the victim declined and then instructed the suspect to get off his property. Initially, the suspect refused, but by the time police arrived, the suspect was gone.
If you do want your energy use checked, Mass Save  offers free audits - which you have to apply for by phone or online, and which typically are scheduled for a few weeks after you contact them.