This Consumer Reports article, focused on reducing energy costs without sacrificing comfort, recommends homeowners hire home performance contractors accredited by the Building Performance Institute.
Consumer Reports recommendations highlighted in this article include having a Home Energy Audit performed by a Building Performance Institute (BPI), installing insulation, air-sealing, programmable thermostats, and possibly upgrading outdated appliances to energy efficient versions. This article also examines energy efficient lighting, mechanical equipment, and alternative energy.
Consumer Reports recommends selecting a BPI accredited provider, as opposed to "fly-by-night companies" or "blow and go" companies. "Choose a contractor certified by the Building Performance Institute. They're required to do an audit before and after any work to guarantee results".
Good advice. Home Energy Saving Tips - Consumer Reports