Do you need a permit to replace a furnace in Michigan?

What the state permit rule says

LARA’s Bureau of Construction Codes states the rule in one line: except for replacement of minor parts, mechanical work shall not be started until a permit has been issued by the appropriate enforcing agency. Homeowners must secure a permit for their own work, and mechanical contractors are responsible for the permits on work they do for an owner.

Then comes the exemption list, which LARA words exactly like this: “portable equipment (heating, ventilation, cooling units, evaporative cooler, gas burners with less than 30,000 Btu/hr.), self-contained refrigeration equipment and window-type air conditioners of not more than 1.5 hp, and oil burners not requiring connection to a flue (oil stoves, heaters equipped with wick).”

Hold a furnace up against that sentence. A furnace is not portable, it connects to a flue and a gas line, and it is not a window unit. A split air conditioner and a heat pump are not on the list either. The conclusion that a replacement needs a permit is our inference from the list, because LARA’s page never says the word furnace. It is a short list, and the inference is not a stretch.

Which code the inspector holds you to

The Michigan Mechanical Code is Part 9a of the state construction code, and rule R 408.30901a adopts the 2021 International Mechanical Code with listed exceptions, effective March 12, 2024. LARA has proposed moving to the 2024 edition, which we describe as a proposal only.

For houses, LARA says one- and two-family provisions sit in the Michigan Residential Code. A Court of Claims order from July 7, 2025 temporarily blocks the 2021 version of that code, so the 2015-based residential code stays in force while the order stands. ICC’s Michigan page has not caught up, so do not rely on it for a house.

Who can pull the permit

Two people can. The first is a licensed mechanical contractor, since Michigan’s statute requires the holder of the license to secure the permit. The second is an owner who occupies a single-family dwelling, installs the system personally and signs the owner affirmation on the application.

If you hire out the work, ask the company for its license number and the permit number once the permit exists. The steps for checking a license are in how to find a licensed HVAC contractor in Michigan. A quote that never mentions a permit is worth a question.

Inspection and concealed work

After a homeowner’s own installation, the applicant must obtain the required inspection once the work is complete and the equipment is running. LARA’s FAQ adds a rule about timing: concealed work may not be covered until it has been inspected, even if the inspector has not shown up within 72 hours. Permits have to be secured before the work starts, and most expired permits cannot be reopened.

Plans are required for a residential home when total heating input exceeds 375,000 BTU/H. A single furnace swap sits well below that, and the figure matters mainly for large or multi-unit systems.

What the permit costs

There is no single Michigan fee, because who issues the permit decides what it costs. Where LARA itself enforces the code, its BCC-9 form lists a $75 non-refundable application fee, $50 for a residential heating system, and $30 each for gas or oil burning equipment, a split air conditioner, a split heat pump and a residential boiler.

Everywhere else the city sets the schedule. These are the ones we read:

• Grand Rapids, effective July 1, 2026: $52 application, which includes one inspection, plus $21 for a furnace or for an air conditioner or heat pump replacement. By our arithmetic a like-for-like furnace swap comes to $73.
• Sterling Heights, 2026 to 2027: a $55 non-refundable application fee, plus $57 for gas or oil equipment up to 75,000 BTU or $64 from 75,001 to 500,000 BTU.
• Dearborn, form dated October 2025: a $100 administrative fee and an $80 minimum permit fee, with $50 for a heating system up to 75,000 BTU and $30 for an air conditioner under 5 tons.
• Westland, form revised July 1, 2026: $100 administrative fee and a $100 minimum permit fee, with $83 for a furnace up to 75,000 BTU. Ask the city whether the minimum raises a single $83 item.
• Warren: an $80 minimum on a form revised in April 2023, so it may be out of date. Troy’s 2026 to 2027 schedule lists a $75 minimum and $98 for a gas burner up to 75,000 BTU, though matching your equipment to its rows is our reading.

We could not read current schedules for Detroit, Livonia, Ann Arbor or Lansing, so call those building departments.

Where the permit comes from

Every one of the 30 cities we researched enforces the mechanical code itself, according to LARA’s Statewide Jurisdiction List (revision of October 6, 2026), so the state fees above rarely apply to a house in a large city. For other places, check the list before you call, because a county or the state may be the enforcing agency. Permits can also be obtained online through LARA’s Accela portal, and the Building Trades Section answers questions at 517-241-9313.

Each city guide names its permit office, for example Grand Rapids and Sterling Heights. A licensed contractor must also register the license with the local enforcing agency, and that registration fee may not exceed $15.

If you disagree with a local inspector, appeal to the local construction board of appeals. Where the state has jurisdiction, the appeal goes to the State Construction Code Commission.

If the permit is skipped

The nearest consequence is a stop order. When work runs contrary to a permit or the act, the enforcing agency gives written notice to show cause within one working day and may then post a stop-construction order.

For whoever did the work, unlicensed practice under MCL 339.5601 is a misdemeanor on a first violation, with a fine of up to $500 or up to 90 days in jail, or both. A second violation raises the limit to $1,000 or one year, and a third or later one is a felony with up to $25,000 or five years. A lapsed or suspended license counts as unlicensed. Those penalties attach to unlicensed work, which tends to travel with a skipped permit.

Related pages

The furnace replacement page covers what the job involves, and the furnace replacement cost guide explains what we can and cannot say about price. A new furnace also changes your carbon monoxide picture, which is why we wrote about alarms and furnaces.