Do you need a permit to replace a furnace, boiler or AC in Massachusetts?

In Massachusetts, most permits are pulled by the licensed contractor doing the work, not the homeowner. For one- and two-family homes the state building code requires a licensed construction supervisor or a registered design professional to oversee construction, and for existing owner-occupied one- to four-family homes the contractor must also be registered with the Home Improvement Contractor program.

The homeowner exception is narrow. The building code lets an owner-occupant of a one- or two-family home apply for a building permit for work on their own home, but it applies to building permits only: electrical work may only be done by a master or journeyman electrician licensed by the state, and plumbing and gas work only by a licensed plumber or gas fitter, each under a permit issued to that licensee. It also has a cost the state warns about directly: a homeowner who pulls the building permit themselves may not be eligible for the Guaranty Fund if the contractor's work goes wrong.

Sources: When is a Construction Supervisor License required?; Massachusetts State Building Code, 780 CMR; HIC Homeowner Resources; Electricians consumer fact sheet; Plumbers and gas fitters consumer fact sheet.

Replacing a furnace, boiler, water heater or central air conditioner, or installing a heat pump or ductless mini split, is licensed work in Massachusetts. Anything on the gas side, a gas furnace, boiler, water heater or range connection, is gas fitting, and the state issues gas-fitting permits only to a licensed plumber or gas fitter. The electrical side of a heat pump, mini split or AC condenser needs an electrical permit pulled by a licensed electrician. Your building department may also require a mechanical permit for the equipment itself; the contractor pulls that too.

Heating and cooling installers are one of the trades mass.gov specifically exempts from Home Improvement Contractor registration, so do not expect an HIC number from an HVAC company. What you should expect is a gas-fitter or plumber licence for gas equipment and an electrician's licence for the wiring, with a permit on file for each.

If you are counting on a Mass Save rebate for a heat pump, the equipment must be installed by a contractor participating in the Mass Save Heat Pump Installer Network. A permit trail is part of how that work is documented, so an unlicensed, unpermitted install can cost you the rebate as well as the inspection.

Sources: Plumbers and gas fitters consumer fact sheet; Electricians consumer fact sheet; HIC Homeowner Resources; Air source heat pump rebates.