What is TSSA registration, and which HVAC work needs it?

The technician grades

Gas technician certification runs in three levels. A G3 works under the supervision of a G1 or G2 holder and may not do the first start-up of a new appliance. A G2 covers appliances up to 400,000 BTU per hour, which takes in most residential and light commercial work. A G1 covers equipment of any size. Oil-fired equipment has its own oil burner technician certificates. Homeowners rarely ask which grade attended, but the certification determines what the technician is legally allowed to touch.

What falls outside it

Work that never touches a fuel line. Installing an air conditioner or a heat pump is refrigeration work, a compulsory trade certified through Skilled Trades Ontario, and anyone servicing equipment that holds refrigerant needs an ozone depletion prevention certificate. The electrical connection falls under the electrical code. That distinction matters more every year as heat pumps take a larger share of the work, because an HVAC business can now be doing a great deal of installation that TSSA's gas rules do not cover.

Outside Ontario

Other provinces run their own regimes with different names and different certificates. A national HVAC brand cannot claim one province's credential everywhere, and a site serving more than one province should say plainly which certifications apply where.