Connecticut licenses HVAC work through the Department of Consumer Protection, and the letters matter: S-2, S-10, B-2, D-2, and G-2 each cover a different slice of the trade. These are the licenses we hold and hire for at American Heating. Here is what each one actually lets you do, in plain English.
Key takeaways
- S-2 is the unlimited journeyperson license: all heating, piping, and cooling work, sheet metal included.
- Limited licenses (S-10, B-2, D-2, G-2) cover narrower scopes and take fewer apprenticeship hours to reach.
- Every journeyperson license runs through a registered apprenticeship or equivalent experience, then a state exam.
- D-2 excludes oil burners entirely, a detail that surprises people in an oil heavy state like Connecticut.
How Connecticut HVAC licensing works
Two license families matter here. Contractor licenses (like S-1) let you run a business and pull permits. Journeyperson licenses (S-2 and the limited classes below) let you do the physical work while employed by a licensed contractor. Nearly everyone starts as a registered apprentice, becomes a journeyperson, and some later step up to contractor.
This guide summarizes the scopes as published by the Connecticut Department of Consumer Protection. Rules change, so before you commit to a path, check the current DCP requirements. If you are deciding whether the trade is right for you at all, start with our honest look at HVAC as a Connecticut career.
The licenses side by side
| License | Type | What it covers | Key limits |
|---|---|---|---|
| S-1 | Contractor | All heating, piping, and cooling work; runs jobs and pulls permits | Requires 2+ years as a licensed journeyperson |
| S-2 | Journeyperson, unlimited | All heating, piping, and cooling work, sheet metal included | Works under an S-1 contractor |
| S-10 | Journeyperson, limited | Heating systems, boilers, steam, hot and chilled water piping; oil, LP, and natural gas within limits | Buildings up to 3 stories; 500,000 BTU heating load; 15 PSI steam; cooling to 35 tons per system; oil to 5 gallons per hour |
| B-2 | Journeyperson, limited | Install, repair, and maintain gas or oil burners | Domestic and light commercial; up to 5 gallons per hour or 500,000 BTU |
| D-2 | Journeyperson, limited | Warm air, air conditioning, and refrigeration systems, plus related piping; LP and natural gas applications | Excludes oil burners of any size |
| G-2 | Journeyperson, limited | Gas piping systems and approved gas appliances | LP and natural gas only |
Why the D-2 oil exclusion matters in Connecticut
A large share of Connecticut homes still heat with oil. A D-2 tech can install your central air and your heat pump but cannot touch the oil burner in the basement. Shops like ours that service everything need S and B class licenses on staff too, which is why holding the right mix makes you more employable.
Each license in plain English
S-2: the do everything journeyperson card
All heating, piping, and cooling work as defined in the statute, sheet metal included. If the shop sends you to any system in any building, the S-2 says you can legally work on it. It takes the most apprenticeship time and classroom instruction, and it is the license that anchors the top of the pay range.
S-10: the heating side, bounded
Heating systems, boilers, steam apparatus, and hot or chilled water piping, in buildings up to three stories with heating loads to 500,000 BTU, steam to 15 PSI, and cooling to 35 tons per system. It also covers oil burners to five gallons per hour and LP or natural gas piping. In practice: nearly all residential and light commercial heating work.
B-2: burners
Installation, repair, and maintenance of gas or oil burners at domestic and light commercial scale, up to five gallons per hour or 500,000 BTU. A focused license for the combustion side of the trade.
D-2: warm air, AC, and refrigeration
Warm air furnaces, air conditioning, refrigeration, and the piping that serves them, plus LP and natural gas applications, with oil burners excluded entirely. If your interest is the cooling and heat pump side of the trade, this is the classic first license.
G-2: gas piping and appliances
Gas piping systems and approved gas appliances, LP and natural gas only. Often paired with another license to round out what a tech can legally touch on a gas job.
Thinking about doing this work for real?
We hold these licenses because we work every side of the trade, and we help the right hires earn theirs. We are a family shop in Waterbury, hiring for honesty and drive since 1978. We are hiring a service technician right now.
From apprentice to journeyperson
You register as an apprentice with the Connecticut Department of Labor, work paid hours under licensed supervision, and complete related classroom instruction. Connecticut technical school materials cite 720 classroom hours on the S-2 path and 432 on the D-2 path, which tells you the limited licenses really are the faster route. When your hours are complete you sit the state exam for your class. The full route, including where the classes happen, is in our apprenticeship guide and our trade school roundup.
How the licenses play out on a real job
Take a common Waterbury project: a homeowner converting from oil to natural gas while adding central air. The gas piping needs a G-2 or broader license. Removing the oil burner and setting the new gas equipment sits in S territory. The air conditioning side fits a D-2. One house, one project, three license scopes, which is exactly why a shop staffs a mix and why a tech holding the right class is never idle.
One project can touch three license scopes. Shops staff for the mix.
The license says what you can legally touch. The apprenticeship teaches you what to do with it.
Exams, renewals, and keeping the license alive
Every journeyperson class ends at a state exam covering the code and the trade practice for that scope. The exam is the gate, and the classroom hours exist to get you through it, so treat night school as exam prep with a paycheck attached, not a formality. Once you hold the license, Connecticut requires renewal and continuing education per current DCP rules; your shop should track this with you, and good shops build code update training into the year.
Which license should you actually target?
Our honest advice after decades of hiring: if you are under 25 and can commit to the longer apprenticeship, go S-2. The unlimited scope pays for the extra classroom time for the rest of your career. If you are switching careers with a mortgage, the D-2 gets you licensed and earning on the cooling and heat pump side years sooner, and Connecticut’s electrification push means that side of the trade is only getting busier. B-2 and G-2 fit people who already know they love the combustion and gas side. There is no wrong door; there is only the door that gets you working.
Frequently asked questions
What is the difference between S-1 and S-2 licenses in Connecticut?
S-1 is the unlimited contractor license, which lets you pull permits and run jobs as a business. S-2 is the unlimited journeyperson license, which lets you do all heating, piping, and cooling work while employed by a contractor. Most techs earn the S-2 first; the S-1 requires years as a licensed journeyperson.
Which Connecticut HVAC license should a beginner aim for?
That depends on the work you want. The S-2 covers everything and takes the longest. Limited licenses like the D-2 (warm air, AC, refrigeration) or B-2 (small gas and oil burners) get you licensed faster for a narrower scope. Many careers start limited and widen later.
Do I need a license to work as an HVAC helper in CT?
You can work as a helper while registered as an apprentice. The apprenticeship registration through the Connecticut Department of Labor is what lets you legally accumulate the hours that lead to the journeyperson exam.
Does a D-2 license let me work on oil furnaces?
No. The D-2 covers warm air, air conditioning, and refrigeration systems and excludes oil burners of any size. Oil burner work at the residential scale runs under the B-2 or the broader S licenses.
Where do I confirm the current license requirements?
The Connecticut Department of Consumer Protection publishes the current license types, scopes, and exam requirements. Requirements change, so check the DCP occupational licensing pages before you plan your path.
Work where the training is paid for
American Heating and Air Conditioning Service pays for training, helps with licensing for some positions, and promotes from inside. Office, helper, apprentice, installer, technician: if you bring honesty and drive, we want your application. One service technician role is open today, and we keep every application on file.
American Heating and Air Conditioning Service
Family owned HVAC contractor, Waterbury CT
We have installed and serviced heating and cooling systems across the Greater Waterbury area since 1978. We work in the same houses we write about. Questions about anything in this article? Call us at 203-756-5040.
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