How to get an HVAC license in Ontario: the 313A trade, decoded

Introduction

HVAC is a compulsory, Red Seal trade in Ontario. Experience alone does not get you on a job site. You legally need a Certificate of Qualification to work on refrigeration and air-conditioning systems for pay. The trade is regulated by Skilled Trades Ontario, the body created under the Building Opportunities in the Skilled Trades Act, 2021 (BOSTA) that took effect January 1, 2022 [1][2].

The headline number people repeat, “you need about 9,000 hours,” is real. It is also only one piece. A working HVAC tech in Ontario almost always holds three credentials: the 313A (or 313D) trade certificate, a TSSA Gas Technician 2 (G2) license, and an Ozone Depletion Prevention (ODP) card. Here is how each one works and how they stack.

313A vs 313D: pick the right ticket

Ontario splits the HVAC mechanic trade into two trade codes:

• 313A, Refrigeration and Air Conditioning Systems Mechanic. Commercial, industrial, and residential systems of any size. This is the Red Seal endorsement and the license most career techs aim for [1].
• 313D, Residential Air Conditioning Systems Mechanic. Limited to residential air conditioning. Shorter apprenticeship, narrower scope, and not Red Seal [3].

If you want to work on commercial chillers, supermarket refrigeration, process cooling, or anything bigger than a split system, you need the 313A. If you only ever plan to do residential AC swaps, 313D gets you there faster. Most contractors hire 313A holders because the 313D does not open the commercial door.

The 9,000-hour apprenticeship, end to end

The 313A apprenticeship is built around roughly 9,000 hours of training over three to five years, split between on-the-job work and three levels of in-school training [4]:

• About 8,280 hours of on-the-job training under a certified journeyperson sponsor.
• About 720 hours of in-school training across three levels (Basic, Intermediate, Advanced).

Each in-school level is typically delivered as an 8-week block at a community college (Mohawk, Conestoga, Centennial, Algonquin, Fanshawe) and is scheduled around your employer’s workload [5][6]. You are paid Employment Insurance during the in-school block under the federal apprentice EI stream, not your employer’s payroll.

You cannot register as an apprentice without a sponsor, meaning an employer with a journeyperson who will supervise your hours. BOSTA caps the apprentice-to-journeyperson ratio at 1:1: one journeyperson can train one apprentice at a time [2][7]. Finding a sponsor is the gatekeeping step most aspiring techs underestimate.

The Certificate of Qualification exam

After all 9,000 hours, you write the Certificate of Qualification (C of Q) exam administered by Skilled Trades Ontario. The pass mark is 70%, and most colleges and private schools (for example, HiMark’s 313A pre-exam course) run dedicated pre-exam prep weeks. Pass it, and you receive your 313A Certificate of Qualification with the Red Seal endorsement [1][8].

The other ticket you actually need: TSSA G2

In Ontario, anyone working on natural gas or propane equipment for pay needs a Technical Standards and Safety Authority (TSSA) gas technician license. There are three levels, G3, G2, and G1. Almost every employed HVAC tech holds at least the G2 [9].

• G3, entry level. Requires a TSSA-approved course and a 75% average on both theory and practical exams. Lets you work under supervision on equipment up to 400,000 BTU/h.
• G2, standalone. Lets you work independently on natural gas and propane equipment up to 400,000 BTU/h (residential furnaces, water heaters, light commercial). This is the working-tech standard [9].
• G1, unrestricted. No BTU/h cap. Required for large commercial and industrial gas work.

Heads up. New rule effective January 1, 2026. G3 certificate holders who earned their G3 through the challenge process (not the standard college path) must show 450 hours of documented G3 work experience on company letterhead before they can enroll in a G2 program [10]. If you are hiring or planning to challenge, factor that gate into your timeline.

The ODP card: refrigerants

Under Ontario Regulation 238/01, you need an Ozone Depletion Prevention (ODP) certificate to purchase or handle CFC/HCFC/HFC refrigerants in the province [11]. The course is a one-day program delivered by HRAI and various private trainers, with a 75% pass mark. The card is valid for five years. If you let it lapse, you retake the full program. There is no shortcut renewal [11].

Running an HVAC business is a separate license

Holding a 313A makes you a qualified mechanic. Operating a refrigeration and AC contracting business in Ontario requires a separate TSSA Certificate of Authorization for Refrigeration / Air Conditioning Contractors issued to the business entity [9]. The business must designate a recognized Refrigeration and Air Conditioning Systems Mechanic as its qualifying technician. This is the layer most apprentices do not see until they go to start their own shop.

The realistic timeline from start to working tech

1. Get a sponsor. Either land an apprenticeship with an HVAC contractor directly, or do a 1-year college certificate first (Mohawk, Centennial, Conestoga) to make yourself hireable.
2. Register as an apprentice with Skilled Trades Ontario. Your sponsor signs the registration. It is free for the apprentice [1].
3. Bank hours. Three to five years of paid on-the-job work, with three 8-week in-school blocks layered in.
4. Take the C of Q exam. 70% to pass.
5. Add the G2 and ODP. Many college HVAC programs bundle the G3, G2, and ODP into the curriculum, so you may already hold them when you finish [4][6].
6. (Optional) Start a business. Apply for a TSSA Refrigeration/AC Contractor Certificate of Authorization with yourself or an employee as the designated qualifying technician.

Realistic time to licensed and working: three to five years if you go the straight apprenticeship route, plus six to eight weeks of dedicated study before each exam.

Where Retrofit.ai fits

Once you are working, the bottleneck is not licensing. It is how fast you can turn leads into quoted jobs. Retrofit.ai’s remote pre-inspection sends homeowners a guided 10-minute photo intake so you can quote heat-pump and furnace installs from your inbox, with auto-computed Manual J load ranges and rebate flags attached. See our companion piece on why every HVAC quote should start with photos for the workflow detail.

Frequently asked questions

How long does it take to get an HVAC license in Ontario?

The full 313A apprenticeship takes three to five years, about 9,000 hours total, split between roughly 8,280 on-the-job hours and 720 hours of in-school training across three levels. The Certificate of Qualification exam comes at the end and requires a 70% pass mark.

What's the difference between the 313A and 313D licenses?

The 313A (Refrigeration and Air Conditioning Systems Mechanic) is the Red Seal endorsement and covers commercial, industrial, and residential systems of any size. The 313D (Residential Air Conditioning Systems Mechanic) has a shorter apprenticeship and is limited to residential air conditioning. Most career techs pursue the 313A because it keeps commercial and refrigeration work in scope.

Do I need a TSSA G2 if I already have a 313A?

In practice, yes. The 313A covers refrigeration and AC mechanics, but Ontario requires a separate TSSA gas technician license to work on natural gas or propane equipment. The G2 lets you work independently on equipment up to 400,000 BTU per hour, which covers most residential furnaces and water heaters. Most working HVAC techs in Ontario hold both.

What is the pass mark for the Certificate of Qualification exam?

Skilled Trades Ontario requires a minimum of 70% on the 313A Certificate of Qualification exam. Most colleges and private schools (HiMark, Skilled Trades College of Canada) run dedicated pre-exam prep weeks for apprentices nearing the end of their hours.

Does an out-of-province HVAC certificate transfer to Ontario?

Yes. The 313A is a Red Seal trade, so a Red Seal-endorsed Refrigeration and Air Conditioning Systems Mechanic certificate from another province is recognized in Ontario. You will still need to add Ontario-specific tickets separately: the TSSA G2 gas technician license and the Ozone Depletion Prevention (ODP) card required under Ontario Regulation 238/01.

Do I need a separate license to start an HVAC business in Ontario?

Yes. Holding a 313A makes you a qualified mechanic. Operating a refrigeration and AC contracting business in Ontario requires a separate TSSA Certificate of Authorization for Refrigeration / Air Conditioning Contractors issued to the business entity, with a designated qualifying technician on staff.