Michigan HVAC License Experience Requirements

The experience documentation phase is where most Michigan HVAC license applications either succeed or stall for months. For the standard classifications, LARA requires 6,000 hours — roughly three years of full-time work — per classification, and the verification standard is far more demanding than most applicants expect. Classifications G and H instead use active-licensure or equivalent-experience pathways.

The 6,000-Hour Requirement

Under MCL 339.5807, the standard mechanical contractor classifications require three years (6,000 hours) of active, hands-on performance in that specific type of work. Classifications G and H instead require three years of active licensure in Class E or F, respectively, or an equivalent qualification. Hours spent installing furnaces don't count toward a refrigeration classification. Hours doing ductwork don't count toward hydronic heating. The experience must match the classification you're applying for.

If you're pursuing multiple standard classifications on your first license, plan to document 6,000 hours per classification with a separate breakdown of the work performed in each scope.

What LARA Actually Requires

This is where applications get rejected. LARA does not accept:

• Self-certified hours
• General employment verification letters
• Vague descriptions of work performed

What they require: a detailed statement signed under penalty of perjury by each present or former contractor who employed you. These affidavits must include:

• A granular distribution of hours across requested classifications
• Technical descriptions specifying equipment BTU ratings, venting and duct system configurations, fuel classes (natural gas, propane, electric), and refrigerant types handled
• The contractor's license number and the period of your employment

A description like "performed residential HVAC service for three years" gets rejected. LARA's licensing section wants something closer to: "Installed and serviced forced-air natural gas furnaces (40,000–120,000 BTU input), central air conditioning systems (1.5–5 ton split systems, R-410A refrigerant), and associated galvanized steel and flexible ductwork in residential and light commercial applications."

Education Substitutions

For a standard three-year classification, two education paths can substitute for up to 2,000 hours (one year) of the requirement:

Approved HVAC technical degree: An associate degree or technical certificate from an approved program counts for up to one year of experience credit. Submit official transcripts with your application.

Registered apprenticeship: Completion of a U.S. Department of Labor-approved apprenticeship program also substitutes up to 2,000 hours. Submit your certificate of completion.

For a standard three-year classification, either path still requires at least 4,000 hours of supervised field experience. Education shortens the timeline but doesn't replace hands-on work entirely.

Military Experience Credit

Veterans get the most favorable treatment under LARA's experience rules. Under MCL 339.5807(3)–(4), active-duty military mechanical service receives full experience credit — meaning qualifying military service can potentially satisfy the entire 6,000-hour requirement.

Required documentation:

• DD214 (Certificate of Release or Discharge from Active Duty)
• DD215 (Correction to DD214, if applicable)
• Experience affidavit signed by a commanding officer detailing the mechanical work performed

The affidavit must describe military mechanical work in the same technical detail LARA requires from civilian employers — equipment types, system specifications, and hours per classification.

When an Employer Won't Sign

This is a real and common problem. Your former employer may have retired, gone out of business, or simply refuse to help a former employee who's now becoming a competitor.

LARA provides a formal appeal process:

1. Send the experience verification form to the former employer via certified mail with a return receipt requested
2. Wait 30 days for a response
3. If they don't respond or refuse to sign, file a formal appeal with the Board of Mechanical Rules
4. Include the certified mail receipt, proof of delivery, and supplemental documentation: W-2 forms, pay stubs, tax transcripts, or any other employment records that corroborate your hours

The Board of Mechanical Rules reviews these disputes during quarterly meetings. Success is not guaranteed — the Board scrutinizes appeals heavily and won't approve them without clear evidence of qualifying work. But it's a legitimate path when a straightforward affidavit isn't available.

Practical Tips for Documentation

Start tracking your hours and work descriptions now, even if you're years away from applying. The people who struggle most with this step are the ones who try to reconstruct three years of work history from memory.

• Keep a running work log with equipment specifications, system types, and hours per project
• Save copies of work orders, invoices, and project documentation
• Maintain contact information for every supervising contractor you work under
• Ask for experience affidavits when you leave a job, not two years later when the relationship has cooled

The Michigan HVAC License Guide includes experience documentation templates and a classification-by-classification hour tracker to help you build your application package before you spend your $300 on the state fee.

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