How to Check Your HVAC Contractor Is TSSA-Registered in Ontario

Short answer: In Ontario, you can check a heating contractor in about 2 minutes on TSSA's free online registry at tssa.org/fuels-contractor. Search by company name or registration number and confirm they're listed for natural gas. Then ask for the name and certificate number of the gas technician who'll actually do the work.

Why it matters

The Technical Standards and Safety Authority (TSSA) registers the companies and certifies the technicians who work on fuel-burning equipment in Ontario, including gas furnaces and water heaters. Unregistered workers, sometimes called "trunk slammers," aren't subject to TSSA audits. If their work is unsafe, you may be the one who finds out, through a failed inspection, a red tag, or worse.

A few minutes of checking before anyone touches your gas appliance is worth it.

Step 1: Look up the company on TSSA's registry

TSSA's public registry of authorized fuels contractors is at tssa.org/fuels-contractor. You can search by:

• Company name or authorization number
• City or postal code of the contractor's main office
• Type of service, such as natural gas, propane or fuel oil

Each listing shows the company name, its TSSA registration number (in the format FS-R- followed by digits) and its address. A few things to keep in mind:

• Match the details. The business name and address on the quote should match the registry listing.
• Check the service type. For a gas furnace or gas water heater, the contractor should be listed for natural gas (or propane, if that's your fuel).
• The list updates monthly. A very new registration may not appear yet. If something doesn't line up, call TSSA before you book.
• A listing isn't an endorsement. TSSA says the registry confirms registration only. It doesn't rate or recommend contractors.

Step 2: Ask about the technician

The company is registered; the person in your basement is certified. TSSA issues gas technician certificates at three levels: G.3, G.2 and G.1. G.1 is the broadest. What each certificate allows is set out in Ontario Regulation 215/01 (Fuel Industry Certificates), so it's fair to ask which certificate your technician holds.

TSSA recommends asking, before any work begins, for:

• The contractor's TSSA registration number
• Their full business name and address
• The name and certificate number of the technician who will do the work

A legitimate contractor will give you these without hesitation. When the technician arrives, it's reasonable to ask to see their identification.

Step 3: Watch for red flags

TSSA also warns that it does not sell products or services. Anyone at your door claiming to be from TSSA and offering to sell you something is not legitimate. TSSA advises not letting anyone in unless you arranged the appointment in advance.

Step 4: Report anything suspicious

If you think someone is working on gas equipment without being registered or certified, or is pretending to be from TSSA, you can report it to TSSA at 1-877-682-TSSA (8772).

A note on safety

If you ever smell gas, leave the building immediately and call your gas utility's emergency line (Enbridge Gas: 1-866-763-5427) or 911 from outside. If your appliance has been tagged unsafe, don't let anyone remove the tag or relight it unless they're a TSSA-registered contractor fixing the problem. See what a red tag means in Ontario.

About our installers

Mr. Heating & Home installs are done by TSSA-registered, insured and bonded gas technicians. When you book, ask us for the installing contractor's TSSA registration number and your technician's certificate details, then check them on TSSA's registry. We'd rather you check.

Frequently asked questions

How do I check if a contractor is TSSA-registered?

Search the company's name or registration number on TSSA's registry at tssa.org/fuels-contractor. If they're not there, or the details don't match, call TSSA before you hire them.

What's the difference between G.1, G.2 and G.3?

They're three levels of TSSA gas technician certificate, with G.1 the broadest. Each allows a different scope of work, set out in Ontario Regulation 215/01. Ask which certificate your technician holds.

Is a TSSA listing a recommendation?

No. TSSA states that its registry is not an endorsement or referral. It only confirms the company holds a valid registration. Check reviews and get a written quote too.

Who do I call to report an unregistered gas worker?

TSSA, at 1-877-682-TSSA (8772).

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Sources: TSSA authorized fuels contractor registry; TSSA: Fraudulent fuels workers campaign resources; TSSA: Verify the legitimacy of all fuels professionals; TSSA: Fuels industry professional certificates. Checked September 2026.