How to get a G3 or G2 gas technician licence in Ontario

Gas work in Ontario is regulated under the Technical Standards and Safety Act, 2000, and the certificates are set out in Ontario Regulation 215/01 (Fuel Industry Certificates). There are three natural gas levels: G3, G2 and G1. Most residential furnace, water heater, fireplace and gas line work is G2 territory, which is why the G2 is the certificate most HVAC employers and homeowners ask about. This guide covers the rules as TSSA published them up to 2026; check tssa.org before you register, because fees and procedures change.

What is the difference between a G3, G2 and G1?

The G1 covers appliances of any size, the G2 covers appliances up to 400,000 BTU/h on your own, and the G3 is a trainee-level certificate that never works alone. The table sets out what each one allows under O. Reg. 215/01.

A G3 can do four kinds of task with a G1, G2 or DA holder readily available but not necessarily on site: gas piping or tubing under 2 1/2 inches from the meter to the appliance valve (including the pressure test tag), putting a previously installed appliance back into service, cleaning and lubricating appliances, and venting work. Those skills must first be signed off by the certificate holder on TSSA's practical skills form. A G3 may never do the first start-up of a new appliance. With the certificate holder on site, a G3 may do anything within that holder's scope.

How do I get a G3 in Ontario?

Take a G3 program with a TSSA-accredited training provider, then pass the TSSA exam and the practical evaluation. The accredited G3 program covers modules 1 to 9 of the gas technician curriculum, with a suggested length of 180 hours, and uses the CSA Group Gas Trade 3 textbooks (Ontario version).

1. Choose an accredited provider: an Ontario college or a registered private career college. TSSA does not process applications from providers that are not accredited.
2. Complete the course with at least 75% in every module and at least 80% attendance.
3. Apply for the exam in the TSSA Client Portal. Once you are approved, book the exam with Prometric.
4. Pass the written exam with at least 75% and the practical evaluation with at least 75%, both within one year of finishing the course.
5. Pay the certificate fee. Your certificate is issued for two years.

Can I challenge the G3 exam without taking the course?

Yes, but only the G3. A person who has never held a gas certificate may challenge the G3 exam, then must pass a practical skills assessment with a TSSA advisor within one year of the written exam. After three failed attempts at any exam you must complete a full accredited program before trying again, and you cannot challenge an exam you have already failed.

The challenge route got narrower for anyone planning to go on to G2. Since January 1, 2026, a G3 holder who got the certificate by challenge must prove 450 hours of G3 work experience before an accredited provider can enrol them in a G2 course. Older forum advice to challenge the G3 and walk straight into a G2 course no longer works.

How do I get a G2 in Ontario?

Hold a valid G3, meet TSSA's G2 entry rule, complete an accredited G2 program, and pass the G2 exam and practical. Under TSSA's gas technician policies revised on April 2, 2025, a G2 candidate must hold a G3 and have either completed an accredited G3 program (exam and practical included), or have at least 450 hours of documented work as a G3.

The 450 hours must be declared on your employer's letterhead, with your start date, the name and certificate number of the G1, G2 or DA holder you worked under, and at least 10 job addresses with the work done at each. Keep a simple log from your first day as a G3; rebuilding ten addresses from memory a year later is the step that holds people up.

The accredited G2 program adds modules 10 to 24, a suggested 480 more hours (660 in total with G3). Challenging the G2 exam instead of taking the course requires 4,000 hours (about two years) of documented work as a G3; work done before you held the G3 does not count. Holders of a Class 1 to 3 operating engineer certificate can go straight to G2 training or the G2 challenge.

How much does it cost to get a G3 and G2?

Budget roughly $1,300 to $1,800 for a G3 course and $2,800 to $4,500 for a G2 course at an Ontario college, plus TSSA fees, textbooks and tools. The course figures are published continuing-education fees for 2025 to 2027 at Durham, Conestoga and George Brown colleges; prices vary by campus and section.

TSSA charges for every exam attempt, including rewrites, and HST applies to its fees. Some colleges also charge their own fee to sit the TSSA exam on campus.

How long does it take to go from G3 to G2?

Part-time, about a year of evenings and weekends: Durham College lists its evening G3 at about 16 weeks and its G2 at about 10 months. Full-time private colleges advertise a G3 in about five weeks and a G2 in about twelve. If you go the work-experience route to G2 entry, 450 hours is roughly three months of full-time work as a G3.

Do I need to renew my gas licence?

Yes, every two years. A TSSA gas certificate expires on your second birthday after it is issued, TSSA invoices about 60 days before, and renewal costs $136 from May 1, 2026, with a $50 late fee. Working on an expired certificate is not allowed; a lapsed certificate is suspended for up to 12 months and then cancelled.

Can I work for myself with a G2?

Yes, but the certificate alone is not enough to sell gas work to homeowners. Under O. Reg. 212/01, anyone carrying on the business of installing, servicing or repairing gas appliances must be a TSSA registered fuels contractor. Registration needs a pre-registration inspection and is renewed every year; for a business with fewer than six technicians, TSSA's fees from May 1, 2026 are $1,042.50 for pre-registration and $506 a year. A one-person business can register with the owner as the certificate holder. A G3 cannot run a gas business alone.

Air conditioning and heat pumps are a separate licence track. A gas certificate covers only the gas side of that equipment; refrigerant work needs a Skilled Trades Ontario certificate (313A or 313D) and an Ozone Depletion Prevention (ODP) card. Liability insurance and WSIB are separate business questions; talk to a broker and an accountant before you take your first job.

I trained outside Ontario. How do I get a TSSA gas certificate?

If you hold a gas certificate from another province, TSSA matches it to an Ontario certificate under Canadian labour mobility rules. For example, Alberta and British Columbia Class B match a G2 and Class A matches a G1; Quebec has no direct match. If you trained outside Canada, TSSA assesses your transcripts and experience and may require an exam, a practical test, or both. Gas technician is not a Red Seal trade, so there is no Red Seal shortcut.

How much do gas technicians earn in Ontario?

Government of Canada Job Bank lists a median wage of $36.06 an hour for gas fitters in Ontario (NOC 72302), with a range of about $26 to $62.50, in data updated November 2025. G2 holders who also hold 313A or 313D and work on their own usually sit toward the top of that range.

Can I take heating jobs on Doyo with a gas licence?

Yes, heating work is one of the trades Doyo books in Toronto and York Region. Doyo checks each technician's TSSA gas certificate before they are offered heating work, and every pro also passes a photo ID check and a police record check. Pros keep their full rate; Doyo's fee is added to the customer's price. Furnace Maintenance on Doyo is $206.50 for the customer, all-in.