Michigan Mechanical License Requirements and Exam: Classifications

To get a Michigan mechanical contractor license, you need at least three years of qualifying hands-on experience under a licensed contractor, a passing score on the state exam in each work classification you want, and a $100 annual license fee paid to the Department of Licensing and Regulatory Affairs (LARA). The license runs on a three-year cycle and covers work on heating, cooling, refrigeration, fire suppression, and related systems.

Who Needs the License

Anyone performing commercial or residential mechanical work in Michigan must hold a mechanical contractor license issued by LARA. The license is not a single credential. It is stamped with one or more of ten work classifications, and you can only pull permits and perform work in the classifications you hold. Working outside your classification carries the same consequences as working without any license.

One boundary to note up front: if your work involves refrigerants, the Michigan license alone is not enough. You also need a federal EPA Section 608 Technician Certification, covered further down.

Experience Requirements

The most common path to exam eligibility under the Skilled Trades Regulation Act is at least three years or 6,000 hours of experience in the specific classification you want to be licensed in.¹ The experience has to be performed under a licensed mechanical contractor whose own license covers that classification. Your employer verifies this by signing a sworn statement describing the work you did, the equipment involved, and how long you did it.²

Military Experience

Equivalent military experience in a relevant mechanical field can substitute for the three-year civilian requirement. You’ll need an affidavit or letter from a commanding officer or supervisor confirming the nature and duration of your service.¹

Education Plus Experience

Graduate from an HVAC program at a recognized trade school, college, university, or a U.S. Department of Labor–designated training program, and the experience requirement drops to two years under a licensed mechanical contractor in your target classification.³

Adding Classifications

Already-licensed contractors can add certain classifications without repeating the full experience track. If you’ve continuously held an active HVAC equipment license for at least three years, you become eligible to test for ductwork, limited or unlimited heating service, and several other classifications. Similar crossover eligibility exists for refrigeration and service license holders.¹

The Ten Work Classifications

Each classification requires its own exam and its own documented experience. You can apply for multiple classifications on a single application, but you’ll sit for a separate test section for each one. The classifications established by statute are:¹

Hydronic Heating and Cooling and Process Piping, covering hot water, chilled water, and steam distribution along with industrial process piping.
HVAC Equipment, covering heating, ventilation, and air conditioning systems including ductwork, gas piping, and venting. This excludes portable self-contained refrigeration equipment and window-type air conditioners of 1.5 horsepower or less.⁴
Ductwork, covering fabrication and installation of duct systems separately from full HVAC equipment work.
Refrigeration, covering commercial and industrial refrigeration systems such as supermarket refrigeration and food storage. Excludes portable units like household refrigerators and dehumidifiers of 1.5 horsepower or less.⁴
Limited Heating Service, allowing maintenance and repair of heating systems but not new installations.
Unlimited Heating Service, covering all heating system service work without the installation restriction.
Limited Refrigeration and Air Conditioning Service, allowing maintenance and repair but not new installations.
Unlimited Refrigeration and Air Conditioning Service, giving full service authority over refrigeration and A/C systems.
Fire Suppression, covering installation and maintenance of fire suppression systems and equipment.
Specialty, covering narrow scopes such as solar heating and cooling, solid fuel appliances, LP distribution piping, and fuel gas piping.⁵

The Exam and Application

LARA administers the exam and tests your knowledge of the Michigan Mechanical Code (based on the International Mechanical Code), the Michigan Residential Code, relevant safety standards, and practical applications for each classification.⁶ LARA publishes a reading list of suggested study materials, including the 2021 Michigan Mechanical Code and the 2015 Michigan Residential Code, both available from the International Code Council or through the Bureau of Construction Codes.

The examination fee for each work classification is $100 or less, as set by LARA, and that fee is separate from the license issuance fee.⁷ Submit a completed application to LARA’s Bureau of Construction Codes along with your work experience reports, proof of identity, and any educational credentials. Incomplete documentation delays processing and testing.²

EPA Section 608 for Refrigerant Work

If your mechanical work involves refrigerants, you need a separate federal credential on top of the Michigan license. The EPA requires anyone who maintains, services, repairs, or disposes of equipment that could release refrigerants to hold a Section 608 Technician Certification under the Clean Air Act.⁸ This applies to contractors holding Michigan’s refrigeration, HVAC equipment, or refrigeration and A/C service classifications.

There are four certification levels:

Type I, for servicing small appliances.
Type II, for servicing or disposing of high-pressure or very high-pressure appliances, excluding small appliances and motor vehicle A/C.
Type III, for servicing or disposing of low-pressure appliances.
Universal, covering all equipment types.

You earn the certification by passing an EPA-approved test, and it does not expire. Apprentices working under the close supervision of a certified technician are exempt while still in training.⁸ For most Michigan mechanical contractors doing meaningful refrigeration or A/C work, the Universal certification is the practical choice because it removes equipment-type restrictions.

Insurance and Workers’ Compensation

Operating as a licensed mechanical contractor means carrying appropriate insurance. General liability insurance protects against claims of property damage or bodily injury arising from your work. Minimum coverage amounts can vary based on scope and the requirements of the jurisdiction where you’re pulling permits, and carrying at least $1 million in general liability coverage is standard practice in the industry.

Some municipalities or project owners also require a surety bond guaranteeing code compliance and completion of contracted work. Bond amounts vary by project scope and local requirements. Failing to maintain required insurance or bonding when a jurisdiction mandates it can put your ability to pull permits at risk.

Workers’ compensation is a separate obligation. Michigan law requires coverage if you regularly employ one or more workers at 35 or more hours per week for 13 or more weeks during the prior year, or if you employ three or more workers at any one time, including part-time employees.⁹ Sole proprietors without employees are not considered employees of their own business and don’t need a policy until they hire staff. If you’re a one-person operation subcontracting to a general contractor, they may require you to carry workers’ comp anyway as a job condition.

Renewal Cycle

A Michigan mechanical contractor license expires on August 31 every third year. To renew, file a renewal application and pay the license fee on or before October 31 of that year. The statutory fee is $100 per year, which totals $300 for a full three-year renewal.⁷

If you’re getting your initial license or relicensing outside the normal August–October renewal window, LARA prorates the fee on a yearly basis for the remaining years in the cycle. Renewal fees themselves are not prorated.

Miss the renewal deadline and your license becomes void for permit purposes. You won’t be able to pull permits or legally perform mechanical work until you apply for reinstatement and pay the license fee. If you reinstate within three years of your license going void, you won’t have to retake the exam.⁷ Wait longer than three years and you’re starting over.

Michigan requires continuing education for mechanical inspectors, plan reviewers, and building officials. The requirement for mechanical contractors specifically is less clearly defined in the statutes. Check with LARA’s Bureau of Construction Codes for current renewal requirements for your classification, since code update training may be required when the state adopts new code editions.

Penalties for Working Without a License

Michigan treats unlicensed mechanical work as a criminal offense. A first violation is a misdemeanor carrying a fine of up to $500, up to 90 days in jail, or both. A second or subsequent offense increases to fines up to $1,000, imprisonment up to one year, or both.¹⁰ Courts can also order injunctive relief, and affected persons who successfully obtain an injunction can recover actual costs and attorney fees.

Administrative Penalties for Licensed Contractors

Licensed contractors who violate the Skilled Trades Regulation Act, its rules, or a LARA order face a separate set of administrative penalties. LARA can impose any combination of the following: an administrative fine of up to $10,000 per violation, license suspension or revocation, license limitation or probation, censure, and mandatory restitution based on findings after a contested hearing.

The conduct that triggers these penalties includes fraud in obtaining or using a license, gross negligence, false advertising, acts demonstrating incompetence, aiding unlicensed work, and failing to comply with a citation or final order. Working outside your licensed classification falls squarely into this territory. LARA can also issue field citations carrying fines of up to $100 per violation for less serious infractions.

Beyond government penalties, consumers harmed by unlicensed or substandard work can file civil lawsuits seeking damages. The statutory remedies and private civil claims are independent, so a contractor can face criminal charges, administrative action, and a civil suit from the same incident.¹⁰

1
Michigan Legislature. MCL Section 339.5807 – Skilled Trades Regulation Act (Excerpt)
2
Michigan Department of Licensing and Regulatory Affairs. Work Experience Report – Mechanical Contractor New Application or Addition of Classifications
3
Michigan Department of Licensing and Regulatory Affairs (LARA). Obtaining a Mechanical Contractor License in the State of Michigan
4
State of Michigan. Application for Mechanical Contractor Examination and Licensing
5
Department of Licensing and Regulatory Affairs. Mechanical Examination, Licensing/Registration and Application Information
6
State of Michigan. Mechanical Contractor and Mechanical Inspector/Plan Reviewer Licensing Exam Reference Materials
7
Michigan Legislature. MCL Section 339.5813 – Skilled Trades Regulation Act (Excerpt)
8
US EPA. Section 608 Technician Certification Requirements
9
Michigan Department of Labor and Economic Opportunity. Employer Insurance Requirements
10
Michigan Legislature. MCL Section 339.601 – Occupational Code (Excerpt)