How to Hire an HVAC Contractor in Ontario
To hire an HVAC contractor in Ontario, check that the company is registered with TSSA and that the technician holds a TSSA gas certificate: only a certified gas technician may install or repair a furnace or other gas appliance. Air conditioner and heat pump work also needs refrigerant certification. Never sign at your door for a furnace, air conditioner or water heater you did not ask about: that contract is void.
How Ontario HVAC contractors compare on ProScore
ProScore lists 1,351 HVAC contractors in Ontario, and has published a ProScore for 1,280 of them. 377 of those reach Trusted (70+) or higher. ProScore matched 410 of them (30%) to the WSIB register by business name. A business that is not matched may still be covered, so ask any HVAC contractor you are considering for a current WSIB clearance certificate. 499 (37%) hold a TSSA licence that ProScore found in force on the register. Look up any business you are considering on the register yourself before you hire.
Counted from ProScore's current listings, refreshed daily. How ProScore scores
Hiring Checklist
What Ontario's rules say
- Pre-approval is mandatory: a heat pump installed before the program approves the application does not qualify, and the model must be on Natural Resources Canada's qualified products list. Home Renovation Savings program
- Under O. Reg. 215/01, only a certified gas technician may install, service or repair a natural gas or propane appliance such as a furnace; a G.2 certificate covers appliances of 400,000 Btu/h or less. Government of Ontario
- Furnaces and other fuel-fired appliances must be maintained by TSSA-registered contractors, and every registered contractor must employ TSSA-certified gas technicians. TSSA
- TSSA's public registry of fuels contractors lets you check that a heating company holds a valid TSSA registration; it is updated at the beginning of each month. TSSA
- Servicing an air conditioner or heat pump that holds refrigerant requires certification, and an Ozone Depletion Prevention card alone is not enough: the technician also needs a Certificate of Qualification in a trade such as refrigeration and air conditioning mechanic. Government of Ontario
- Under the Consumer Protection Act, a business may not solicit or sign a contract at your home for the goods and services the law prescribes unless you contacted it first and asked it to come for that purpose, and a contract made in breach of that rule is void. Government of Ontario
- The goods and services prescribed for that rule are furnaces, air conditioners, air cleaners, air purifiers, water heaters, water treatment devices, water purifiers, water filters, water softeners and duct cleaning. Government of Ontario
- Since June 6, 2024, a business can no longer register a Notice of Security Interest on your home's title for consumer goods such as a furnace, air conditioner or water heater. Government of Ontario
Red Flags to Watch For
Quotes without visiting your home
No legitimate HVAC contractor can properly size a system without assessing your home in person.
Only offers rental/lease options
Some companies push 10–16 year equipment leases that cost 40–60% more than buying. Always get a purchase quote too.
Not TSSA registered
Gas appliance work by unregistered technicians is illegal and dangerous. Verify at tssa.org.
Will not specify the equipment brand/model
Vague quotes with “high-efficiency furnace” but no brand/model make comparison impossible.
Extreme low or high pressure
Either an unrealistically low price (corners will be cut) or high-pressure “sign today” tactics are red flags.
No mention of permits
Gas appliance installations require TSSA permits. If the contractor does not mention them, ask why.
Questions to Ask Before Hiring
“Are you TSSA registered for gas work?”
“Will you do a heat loss calculation?”
“What brand and model are you quoting?”
“What rebates does this system qualify for?”
“What is your labour warranty?”
Licensing: Technical Standards and Safety Authority (TSSA)
TSSA regulates fuel-burning equipment in Ontario, including furnaces, water heaters, and gas fireplaces. All technicians working on gas appliances must be TSSA-registered. You can verify any contractor on the TSSA website.
Verify at Technical Standards and Safety Authority (TSSA) →Frequently Asked Questions
Do HVAC contractors need a TSSA licence?
For any gas appliance work, yes. Electrical-only HVAC work (heat pumps, AC) does not require TSSA but does require an ESA licence.
Should I rent or buy my furnace?
Buying is almost always cheaper long-term. A furnace that costs $3,500–$8,500 to buy and install is typically paid for several times over across a 10–16 year rental contract.
How do I know what size furnace I need?
A proper heat loss calculation factors in your home’s size, insulation, windows, and climate zone. Do not trust estimates based on square footage alone.
What AFUE rating should I look for?
Ontario’s building code requires 95%+ AFUE for new installations. Higher ratings (98%) cost more upfront but qualify for more rebates.
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Sources
- Home Renovation Savings program, Home Renovation Savings: heat pumps (Program page, October 2026). Accessed October 19, 2026.
- Government of Ontario, O. Reg. 215/01: Fuel Industry Certificates. Accessed October 19, 2026.
- TSSA, Be Fuels Wise: hire registered and certified professionals (News release, March 1, 2024). Accessed October 19, 2026.
- TSSA, Authorized heating fuel contractors. Accessed October 19, 2026.
- Government of Ontario, Certificate to handle refrigerants. Accessed October 19, 2026.
- Government of Ontario, Consumer Protection Act, 2002, s. 43.1. Accessed October 19, 2026.
- Government of Ontario, O. Reg. 17/05 (Consumer Protection Act, 2002), s. 35.1. Accessed October 19, 2026.
- Government of Ontario, Notices of Security Interest. Accessed October 19, 2026.
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