Gas Safety and Planning
Ontario Gas Fitter Qualifications: G1, G2 and Contractor Registration
Ontario regulates the contractor business and the individual technician through different mechanisms. Homeowners should verify both for the planned work.
Before you compare
Start with the property and equipment
In Ontario, G1 and G2 are individual certificate categories with different scopes, while a fuels-contractor business must be registered with TSSA to contract for regulated work. A G2 generally works on approved gaseous-fuel appliances and equipment up to the certificate's rated-input limit; a G1 has a broader input scope and prerequisite experience. The homeowner should verify the current contractor record and ask how the attending technician's certificate covers the exact project.
Separate the company from the certificate holder
A fuels contractor is the business that offers and contracts for regulated work. TSSA maintains a public contractor directory. A gas technician is an individual holding a certificate category that authorizes specified work, subject to conditions and scope. A technician certificate does not automatically register an unrelated business.
When reviewing a quote, match the business name to the directory and ask who will perform the work. The invoice and warranty path should use the same accountable business identity. This two-layer check is more precise than asking only whether someone is "licensed."
- Verify the contractor business in the TSSA directory.
- Ask which certified individual will attend.
- Match the certificate scope to the project.
- Keep the quote and invoice under the verified entity.
What G2 commonly means
The G2 certificate covers work on specified gaseous-fuel appliances and equipment within the rated-input scope set by Ontario rules and training requirements. It is widely relevant to residential fireplaces, pool heaters, ranges and gas lines when the appliance and system fall within that scope. Exact authorization still depends on the task and conditions.
A homeowner should not total inputs and independently decide that a certificate applies. Ask the contractor how the project is assigned and supervised. Multi-appliance systems, larger equipment or unusual work may require different qualifications or oversight.
What G1 adds
G1 is a higher certificate category with broader rated-input scope and experience prerequisites. It is relevant to larger equipment and work beyond the G2 limit, but "higher" does not make every G1 the right contractor for every residential project. Registration, equipment experience, current status and a complete scope still matter.
For a typical homeowner quote, the useful question is not whether the company can advertise its highest credential. It is whether the business and assigned technician are authorized and experienced for the specific fireplace, gas line, pool heater or appliance work being proposed.
- Broader input scope does not replace contractor registration.
- Certificate category is one part of project fit.
- Current status and conditions matter.
- Relevant equipment experience remains valuable.
Before you choose equipment
Check the model against the property
Compare the exact model with the structure, fuel or electrical supply, clearances, venting, access and service needs at the property.
Why supervision and task boundaries matter
Projects can include apprentices, helpers and several trades. The registered contractor is responsible for assigning regulated work within qualification and supervision requirements. Electrical, excavation, masonry, pool-water and structural scopes may belong to other qualified parties.
Ask the quote to identify responsibilities rather than assume one certificate covers every part of a renovation. A clean handoff includes who sizes and installs the fuel system, who supplies electrical work, who creates openings or finishes, and who commissions the appliance. Unclear trade boundaries can produce both delays and unsafe improvisation.
Verify current records instead of marketing language
Use TSSA's official contractor search and official certification information. Search the legal and operating names, compare location details and note the date. If a listing cannot be reconciled with the quote, contact TSSA. Do not rely on a copied badge, old certificate photograph or a directory hosted by an unrelated lead-generation site.
Ask the contractor to explain terminology accurately. A company that distinguishes registration from individual certification and answers scope questions clearly gives the homeowner useful evidence. Treat registration details as current only after checking TSSA's official records.
- Official TSSA directory.
- Exact business identity and location.
- Current date of verification.
- Direct clarification for any mismatch.
Apply the credentials to a written residential scope
A sound scope names the fuel, appliance or load, route and existing-system assumptions, regulated work, equipment, testing and commissioning, permits or inspection responsibilities where applicable, related trades and exclusions. Credentials do not turn a vague quote into a complete one.
Preserve the scope, changes, final invoice, manuals and records supplied at completion. For service, keep the model, serial and findings. The hiring decision should account for both authorization and who remains accountable for the work, without asking the homeowner to become the technical authority.
Compare qualifications without oversimplifying them
Certificate category answers a regulatory scope question; it does not rank customer service, fireplace design ability or pool-system knowledge. Compare relevant project experience, current manufacturer documentation, written communication and the plan for related trades alongside authorization. A larger credential number is not a substitute for a precise residential scope.
Conversely, years of informal experience do not replace required registration and certification. The strongest hiring evidence is the combination: current official records, a technician assignment that fits the work, transparent assumptions and a documented completion process. That gives the homeowner a fair basis for comparing bids without making technical judgments outside their role.
Questions we hear
Frequently asked questions
No. The required certificate depends on equipment input, task and scope. G2 commonly covers many residential appliances within its limits, while larger or different work can require G1 or other qualifications.
No. Registration applies to the fuels-contractor business. G2 is an individual technician certificate category. Verify the business and the people assigned to regulated work.
Individual certification does not replace the business registration required to contract for regulated fuels work. Confirm the accountable contractor in TSSA's current directory.
Start with TSSA's official contractor and certification resources. Contact TSSA directly when names, scope or current status are unclear.
References
Sources and further reading
Request a quote
Tell us about the property and equipment
Send us the service address, timing, appliance model and photos that show the work area.