Remember the now-classic career advice offered to the Dustin Hoffman character in the 1967 film “The Graduate”? At a party his parents have thrown for him, the young grad is button-holed by a middle-age family friend, who says as if letting him in on the secret to success: “I want to say one word to you. Just one word.” He leans in, conspiratorily, and says: “Plastics.”

The updated version of the one-word career advice would be: insulation. Or maybe it’s “weatherization.”

The growth field of tomorrow will relate to energy in some manner. And as has been repeated again and again, money spent tightening up is a better investment than new heating methods.

MaineHousing, the state’s housing agency, recently doubled the size of the class it is offering to train weatherization technicians and energy auditors. Energy auditors assess a home or business building’s heating loss weaknesses. Typically, they hang a curtainlike device over the open front door, and with all other windows and doors closed, turn on high-powered fans, blowing out. The process allows the auditor to observe where outside air leaks into the building, so the gaps can be sealed.

The agency now offers two energy auditor classes a month. It will increase the class size from 12 people to 24 people.

Over the next four months, MaineHousing expects to train more than 200 people as certified energy auditors and 500 as weatherization technicians. That amount won’t put a big dent in the unemployment numbers, but it’s a job demand worth noting. Presently, there are about 100 certified energy auditors in Maine, but many work for nonprofit organizations and are not available for private customers. Some nonprofits, such as some community action programs, are allowing the auditors to do private work.

Perhaps Maine’s technical high schools will create a curriculum that covers, in a survey format, energy auditing, insulation installation, best-practices for building energy-efficient structures, installation of pellet stoves and on-demand hot water heaters and the like.

Of course, after everyone tightens up their home and business buildings, being a certified energy auditor or insulation installer might be as marketable as being an 8-track player repair person. But since Maine has some of the oldest houses in the country, being in on the ground floor of the movement to improve those buildings, with an eye to energy-efficiency, is probably a pretty safe employment bet.

MaineHousing’s course is two weeks long and costs $550. The list of energy auditor classes held in several different communities, may be found at: mainehousing.org/ENERGYTrainingSchedule or by calling 624-5778.