A master HVAC license is the top individual license a state, city or county issues to an HVAC worker — the credential for supervising the work, pulling permits and qualifying a company.
What it takes is written state by state: New Jersey asks 5 years in the trade, Maryland 3 years as a licensed journeyman plus 1,875 hours, Delaware 2 years under a master.
Only two states license HVAC at the master level alone.
What does a master HVAC license let you do?
A master HVAC license is an individual credential — the top rung for a worker, above journeyman — but no federal agency defines it.
What "master" means, what it legally allows and what it takes to earn one are written in each state's licensing law, and they differ state by state.
The pattern in the states that use the rung is consistent, though: the master is the person legally in charge of the work.
That shows up first in who may work at all.
A Delaware HVACR business must have a Master HVACR (or Master HVACR Restricted) licensee supervising its workers, and unlicensed employees may only do HVACR work under a master who is their employer or works full time for the same business.
A New Jersey HVACR business operates through a "bona fide representative" — a licensed master HVACR contractor — and must hold a pressure seal to pull HVACR permits.
Rhode Island goes further: no one may contract, advertise or employ others in refrigeration and air-conditioning work without a master license, and the master license number must appear on ads, contracts, bids and permits.
Iowa requires any business doing mechanical work to employ a licensed master who is actively in charge at all times, and a sole proprietor must personally hold the master license.
The license also defines your scope of practice.
A Maryland master may provide all areas of HVACR work; the Master Restricted license narrows that to one or more areas — air conditioning, forced-air heating, hydronic heating, ventilation, refrigeration — and Delaware's Master HVACR Restricted license is limited to a single specialty such as refrigeration, air conditioning or hydronic heating/gas piping.
Master does not fold in the neighbouring trades: a Delaware Master HVACR needs a separate Master Plumber license for water supply and drainage work, and a New Jersey master may not replace an electrical disconnect box or switch — that takes a licensed electrician, though an Iowa master may disconnect and reconnect existing air-conditioning and refrigeration systems without one.
Whether the rung is worth the years it costs is partly a market question.
Browsing live HVAC technician jobs shows how often employers in your area ask for master-level credentials in the posting itself.
Confirm the license with the board that issues it
Which states have a master HVAC license?
Only two states license HVAC at the master level and nothing below it: Delaware and New Jersey.
Delaware's Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners issues only master-level licenses — Master HVACR and Master HVACR Restricted — and in both states an unlicensed technician may do HVACR work as an employee of a licensed master without holding a license of their own.
They are the exceptions, though: only about a quarter of U.S. jurisdictions license HVAC workers at any individual rung, while the rest license the contractor or business only, license the master level only, split the work into pieces, or leave HVAC to cities.
Elsewhere, "master" is the top of a ladder that starts with an apprentice or journeyman license:
- District of Columbia — refrigeration and air-conditioning mechanics are licensed individually at apprentice, journeyman and master levels, with "limited" versions for equipment at or below 25 compressor horsepower
- Maryland — the HVACR Board's ladder runs Apprentice, Journeyman, Journeyman Restricted, Limited, Master Restricted and Master
- Iowa — master licenses exist in the mechanical, HVAC-refrigeration and hydronic disciplines, alongside journeyperson licenses
- Rhode Island — the Department of Labor and Training's mechanical board licenses masters, journeypersons and apprentices in air conditioning/refrigeration, pipefitting, sprinkler fitting and sheet metal
- Virginia — tradesman levels for HVAC are residential tradesman, journeyman and master
- Kentucky — the Department of Housing, Buildings and Construction licenses a master HVAC contractor, a journeyman HVAC mechanic and an apprentice — a master name with contractor powers, covered below
Where the state stays out, the master title often survives locally.
Kansas law recognizes three local HVAC license types: mechanical HVAC contractor, master HVAC mechanic and journeyman HVAC mechanic.
Omaha issues a Master ACAD license, Casper a Mechanical Master, and Sioux Falls routes contractors through its Master Mechanic exam.
Fargo proctors North Dakota's master and journeyman HVAC exams for participating jurisdictions, and Nashville's local board issues master mechanical and HVAC&R certificates.
Pittsburgh's Mechanical Trade License goes to individuals who pass the ICC National Standard Master Mechanical exam, New Orleans issues its own Class "A" Master Mechanical Contractor license, and Denver's top Heating and Ventilating certificate is the Class A Supervisor.
The full state-by-state map of who licenses what is in our guide to HVAC license requirements.
One warning about the words themselves: if you searched for a "Class A HVAC license," you mostly land on contractor tiers, not the master license.
Texas licenses ACR contractors in Class A — any size equipment — and Class B, up to 25 tons cooling or 1.5 million BTU/hour heating, with E, R or C endorsements for environmental air conditioning, commercial refrigeration, or both; Texas has no journeyman or master HVAC tier at all, only Registered Technician, Certified Technician and the ACR Contractor license.
Florida's Class A air-conditioning contractor is likewise a business license, unlimited in scope, and Georgia licenses conditioned air contractors in Class I and Class II with no individual worker license.
The pattern is not universal, though: New Orleans's Class "A" sits on a master title.
Class letters name whatever the issuing body attached them to — before you chase one, check which license your state's "Class A" actually is.
What experience and exam does it take?
No federal rule sets the years, hours or exam — each licensing body writes its own.
The verified requirements show how differently the same word "master" is priced:
- New Jersey — to sit the Master HVACR exam you must be at least 21 with 5 years in the HVACR business, at least 4 in a U.S. Department of Labor-approved apprenticeship or training program and at least 1 as a journeyperson (or licensed plumber); the board accepts four education routes. The exam has two written parts — HVACR practice and NJ laws and rules — with at least 70 required on each, scheduled through PSI, and a failed part means a 6-month wait to retake. Fees run $100 to apply and $160 for the initial license, with a $160 renewal every two years plus 5 credits of board-approved continuing education.
- Delaware — qualify with a journeyman certificate from an apprenticeship meeting federal standards plus 2 years under a master, or 7 years under a master plus the apprenticeship equivalency ("by-pass") test given by a Delaware vocational-technical school. Master applicants for refrigeration or air conditioning must hold EPA CFC (Section 608) certification at the appropriate level. Exams are administered by ProV; the by-pass exam by ABC Delaware. The application fee is $173.
- Maryland — at least 3 years of active experience as a licensed journeyman under a master, at least 1,875 hours worked in the year before applying, and a 70% score on the master exam. The Master Restricted license carries the same experience rule. The master license fee is $94.50 as of July 1, 2025.
- District of Columbia — at least 5 consecutive years immediately before applying, spent working on systems larger than 25 compressor horsepower and verified in writing by a master; the limited master needs 5 years on systems under 25 hp plus CFC certification.
- Iowa — a master license requires at least 2 years of experience as a licensed journeyperson in the discipline plus the master exam (or a prior master license), at the top of the apprentice → journeyperson → master ladder.
- Rhode Island — 1 year as a licensed Rhode Island journeyperson, or an equivalent master license from another state, before you can sit the mechanical master exam; the Refrigeration Master I license runs $75 to test and $240 for the license itself.
The local cards follow the same logic at city scale.
A Kansas master certificate takes 2 years as a journeyman or 4 years of field experience.
Fargo's master exams require 6,000 hours of journeyman experience plus 4,000 hours of practical experience — 10,000 hours total — at $125 per master exam appointment.
Sioux Falls's Master Mechanic exam requires 4 years' experience, costs $75, is offered monthly and passes at 75%.
Pittsburgh wants at least 4 years of combined experience and education behind the ICC exam.
Denver's Class A Supervisor certificate asks for 8 years of commercial heating and ventilating work — 4 as a journeyman mechanic and 4 as a designer, draftsman or supervisor — plus ICC exam F29.
New Orleans takes an ICC G29 Master Mechanical exam report, Omaha's Master ACAD requires an exam and $50 plus a $4 technology fee to start, and Casper's Mechanical Master license is $75.
Notice what the list does not contain: a standard.
The same word "master" means 5 years in one state, 10,000 hours in one city and 8 years of mixed design work in another.
Treat the number you find as that jurisdiction's number, current as of its source — and verify it before you build a career plan on it.
Book against the current bulletin, not an older article
Is a master HVAC license the same as a contractor license?
Sometimes yes — that is the surprise in this rung.
In Maryland, Delaware, New Jersey, Kentucky, Connecticut and Rhode Island, the master-level individual license doubles as the contracting license.
Delaware has no separate contractor license from its board at all: the master license is the practice license, and a business's workers simply operate under a master the business employs.
Maryland has no separate company license either — contracting is done under an individual Master, Master Restricted or Limited HVACR license, and licensees who sign or approve contracts must carry at least $300,000 general liability and $100,000 property damage insurance, $400,000 combined, naming the HVACR Board as certificate holder.
Kentucky shows the fused model in the license's own name: master HVAC contractor.
It takes 2 years as a journeyman HVAC mechanic under a master — or 2 years as a master-equivalent contractor elsewhere, or as a licensed mechanical engineer — plus the exam.
The holder must be the company's master in responsible charge, and must notify the department when that employment starts and ends.
The exam costs $150 and the license renews at $250 a year.
And the dependency runs one way: if a Kentucky company's master dies, the company may keep using the license for up to 180 days while it finds a new one to pull permits.
Elsewhere the master is the qualifier behind a separate contractor license.
Virginia law requires a master tradesman license as a condition of licensing HVAC contractors, and the qualified individual for an HVA contractor must hold the Master HVAC tradesman license.
An Iowa contractor license requires holding a master license or employing at least one master licensee.
New Orleans allows only one Class "A" Master Mechanical Contractor license holder per company.
What the business side adds on top of the master license — bonds, insurance minimums, pressure seals, business registration and the statewide contractor classes — is its own subject.
Our guide to the HVAC contractor license by state covers it from the employer's side.
And if you have not yet earned your HVAC journeyman license, start there: in the states examined here, master requirements are measured in journeyman years.
This page is career information, not legal or licensing advice. Master licensing is set by state boards and, where licensing is local, by city and county offices — confirm the current requirements with the authority for where you work before you apply, sit an exam or sign contracts.