Texas HVAC License Classes Explained: Class A vs Class B, Endorsements & the 48-Month Rule

Two questions, not one

Most people search “how to get a Texas HVAC license” expecting a single credential. TDLR actually makes you answer two separate questions, and your license number records both answers. The class answers how big: what size equipment you may install, repair, or maintain. The endorsement answers what kind: comfort systems for people, or refrigeration and process systems for product. Get either one wrong on the application and you can hold a perfectly valid license that does not cover the work your customers are calling about.

Anyone who installs, repairs, or maintains air conditioning, refrigeration, or heating systems in Texas must hold a TDLR license, or work under someone who does. So the class-and-endorsement decision is not paperwork. It is the legal boundary of your business.

Class A vs Class B: the size line

TDLR describes the two classes in one sentence each. A Class A license allows you to work on any size unit. A Class B license allows you to work on cooling systems of 25 tons and under, and heating systems of 1.5 million BTUs/hour and under.

For scale: a typical Texas house runs a three- to five-ton system. A small strip-center suite might be ten to fifteen tons. Twenty-five tons covers nearly all residential and light-commercial work, which is why Class B is the common starting point for a service company. The line matters the day a property manager asks you to look at a forty-ton rooftop unit or a packaged system on a warehouse. With a Class B license, that call is not yours to take, no matter how competent you are.

Both classes use the same application, the same experience rules, and the same one-year exam window. What changes with Class A is the exam and the insurance minimums, which we cover below.

Class limits, endorsement definitions, fees, and experience rules above are from TDLR’s ACR contractor application and exam pages, current as of October 2026. Rules and fees change — confirm with TDLR before you file.

The three endorsements, in plain language

Environmental Air Conditioning is comfort work: the air people breathe. TDLR defines it as treating air to control temperature, humidity, cleanliness, ventilation, and circulation. Central air, furnaces, heat pumps, ductwork, ventilation — the bread and butter of a residential and commercial HVAC company.

Commercial Refrigeration is product work: the use of mechanical or absorption equipment to control temperature or humidity. Process Cooling or Heating is production work: controlling temperature, humidity, or cleanliness solely for production requirements. TDLR groups these two together and limits them to coolers, freezers, ice machines, and equipment that provides temperature and humidity controls. Walk-in boxes, reach-ins, supermarket racks, restaurant ice machines, and the chilled loops behind a manufacturing line all live here.

The practical trap is assuming refrigeration skill transfers to the license. A technician who has spent four years on supermarket racks and applies for Environmental Air has documented the wrong experience for the wrong endorsement. Match the endorsement to the work you have actually done and the work you intend to sell. If your business later grows into the other side, TDLR lets you add an endorsement to an existing license with a change form and a $25 fee rather than starting over.

PSI runs a separate exam for each combination — Environmental Air A, Environmental Air B, Commercial Refrigeration A, Commercial Refrigeration B — so your choice on the application decides which test opens for you.

The 48-month rule and the certified-technician shortcut

Texas does not license HVAC contractors on an exam alone. You first have to prove supervised field time, and TDLR accepts exactly two ways to do it.

Path one: at least 48 months of practical experience in air-conditioning and refrigeration-related work under the supervision of a licensed contractor, within the past 72 months. Four years of work inside a six-year window.

Path two: you have held an ACR technician certification for the past 12 months, plus at least 36 months of supervised experience within the past 48 months. Certification is voluntary in Texas, but this is where it pays: it trims a year off the experience requirement for the contractor license.

Either way, the experience goes on TDLR’s Experience Verification Form, and the department is blunt about who fills it out: do NOT complete this form yourself. The contractor or contractors who supervised you sign it, and you can submit more than one form if you worked for more than one shop. Start collecting those signatures early. A supervisor who has retired, moved, or closed the business is the single most common reason an otherwise qualified application stalls.

Fees, the exam clock, and the insurance you cannot skip

The application fee to TDLR is $115. Once TDLR approves your eligibility it notifies PSI, the state’s exam provider, and PSI emails you instructions to register, pay the exam fee, and schedule. The passing score, question count, time limit, and the reference materials you may bring are all published in PSI’s Candidate Information Bulletin, and you should read it before you book.

Then the clock starts. TDLR states that you must complete all requirements of the application process, including passing the licensing exam, within one year of the date the application is filed. If you fail, PSI lets you schedule a retake within a day or two, and you may keep retaking until the application expires. After that, you file a new application and pay again.

The last requirement is the one new contractors forget to price in. You must carry commercial general liability insurance at all times while the license is active, from an insurer authorized in Texas. The minimums rise with the class:

Once licensed, the credential renews every year with eight hours of continuing education — see Texas HVAC license renewal for the annual clock and the four ways real certificates get rejected.

Registered vs certified technician: the credential most people start with

Not everyone needs the contractor license. TDLR states that a person assisting a licensed contractor with ACR work must hold a designation as either a registered or certified technician, and must work under the contractor’s supervision. Technicians cannot advertise air conditioning and refrigeration services on their own.

Registration is the entry point. Certification, in TDLR’s words, is a voluntary qualification that exceeds the standards of Registered Technician designation: you need 24 months of supervised experience or a department-approved program of 2,000 hours of combined instruction and practical experience, a $50 application, and a passing score on the Certified Technician exam. The payoff is the shorter path to the contractor license described above, and a title only certified technicians may use.

Why the class and endorsement should be taught, not memorized

Generic exam prep treats the licensing structure as a list to memorize: two classes, three endorsements, 25 tons, 1.5 million BTUs, 48 months, 72 months. You cram the numbers, pass the quiz, and a year later cannot say whether a 30-ton chiller on a restaurant roof is a Class B job or whether a walk-in cooler is Environmental Air. The numbers were never connected to the equipment they describe.

CortovaTempTX is built on the opposite idea. Equipment is drawn and animated — a five-ton split system beside a forty-ton rooftop unit beside a supermarket rack, each labeled with the class and endorsement that covers it. The Texas law hour walks through TDLR’s actual rules the way a contractor reads them: what the license lets you sell, what it does not, and where good companies get burned. And every module carries an audio overview, so the review happens on the drive between calls.

Difficult subjects can be simplified to be understood. A licensing boundary is only confusing until someone shows you the equipment on each side of it.

CortovaTempTX is in production now, with TDLR submission ahead — the course page carries the current status.