Michigan Mechanical Permit Requirements

A state Mechanical Contractor License gets you authorized to do HVAC work in Michigan. But it doesn't get you onto a job site — you still need a mechanical permit from the local building department before starting any installation, replacement, or major alteration. Understanding who can pull these permits and when they're required saves you from stop-work orders and double-fee penalties.

Who Can Pull a Mechanical Permit

Under the State Construction Code Act (1972 PA 230), only a licensed Mechanical Contractor of record can pull permits for commercial or residential work performed for compensation. Not a technician, not a trainee, not someone with only an EPA 608 card.

This is a common trip-up for service techs who've been working under someone else's license. If you show up at a municipal building department with just an EPA certification and try to pull a permit for a furnace changeout, they'll turn you away. The permit requires a state-level Mechanical Contractor License number.

There's one exception: owner-occupants of single-family homes can pull their own mechanical permits for work they personally perform. They must sign an affidavit certifying they'll do the work themselves, follow the Michigan Mechanical Code, and not cover or operate the system until it passes inspection. Using a homeowner permit to cover unlicensed contractor work is a civil violation under Section 23a of the Construction Code Act.

When Is a Permit Required?

Almost any time you're installing, replacing, or making major alterations to mechanical equipment. Even a like-for-like furnace replacement — same capacity, same fuel source — requires a mechanical permit and inspection in nearly every Michigan jurisdiction.

Work that typically requires a permit:

• Furnace replacement or installation
• Central air conditioning installation
• Ductwork modifications or new runs
• Boiler installation or replacement
• Commercial refrigeration installation
• Heat pump systems
• Gas piping connections to mechanical equipment

Routine maintenance is generally exempt: changing filters, cleaning coils, lubricating motors, and similar service tasks don't trigger a permit requirement.

The Inspection Process

Local authorities may require a rough-in inspection (before walls and ceilings close up the ductwork, venting, and gas lines) and a final inspection (after the system is operational).

Inspectors evaluate compliance with the Michigan Mechanical Code and focus on venting configurations, combustion air supply, clearance to combustibles, condensate drainage, and low-voltage thermostat wiring. If any work crosses into the electrical or plumbing scopes without separate permits, the inspector will flag it.

Failed inspections carry re-inspection fees — $50 in Center Line, for example — and you can't close the permit until deficiencies are corrected.

What Happens If You Skip the Permit

Some municipalities impose an investigative fee equal to the total permit cost on top of the regular permit fee when work starts before permit issuance. Center Line is one example. In Detroit, BSEED can issue a stop-work order that halts the entire project until you come into compliance.

Beyond the immediate penalties, unpermitted work can't be inspected, which means the system has no code-compliance record. This creates liability for the homeowner at resale and for you if anything goes wrong with the installation.

Municipal Variations

While the state sets the rules for who needs a license, local jurisdictions control the permitting process. Fees and timelines vary significantly:

• Detroit: $203 flat mechanical replacement fee, 24-hour standard permit turnaround through BSEED's Accela portal
• Grand Rapids: Base fee plus itemized equipment fees ($30 per furnace, $30 per AC unit), 1–2 business day review
• Center Line: $75 non-refundable admin fee plus $70 per inspection, with a double-fee penalty for starting work before permit issuance
• Ann Arbor: $75–$300 based on project complexity, 1–2 week processing, 24-hour advance notice for inspections

Local registration is also required before you can pull permits in a municipality. State law caps the registration fee at $15 per jurisdiction.

The Michigan HVAC License Guide includes a municipality-by-municipality breakdown of registration requirements, permit portals, and fee schedules for the state's largest jurisdictions.

See more Michigan guides →