10 Questions to Ask Your Furnace Contractor Before Signing

Why the Questions You Ask Before Signing Matter More Than the Price

A furnace installation in Canada typically runs between $3,500 and $8,500 installed, depending on the equipment tier, province, and complexity of the job. That is not a trivial purchase. Yet most homeowners spend more time researching a $400 appliance than they do vetting the contractor who will cut into their gas line, modify their ductwork, and commission a heat exchanger that — if improperly done — can leak carbon monoxide into their home. The bid sheet tells you the price. The conversation before you sign tells you whether you are dealing with a true professional.

Canadian winters are unforgiving. In Edmonton or Winnipeg, a furnace that goes down in January with a poorly qualified installer at the helm can leave a family in a genuinely dangerous situation. Beyond immediate safety, a botched installation voids manufacturer warranties, fails municipal permit inspections, disqualifies you from provincial and federal rebate programs, and creates years of recurring service calls. The 10 questions in this guide are drawn from what Red Seal Gas Technicians and HVAC inspectors actually look for when they walk into a home. Ask them all before a single signature lands on paper.

Question 1: Are You Licensed, Insured, and Gas-Certified for My Province?

Licensing in the HVAC trades is provincial, not national. In British Columbia, a contractor must hold a Gas Fitter licence issued by Technical Safety BC (TSBC) — Class A or B for residential gas work. In Alberta, the provincial authority is ABSA and work must be performed or directly supervised by a licensed Gas Fitter. Ontario requires a G2 or G3 ticket under the Technical Standards and Safety Authority (TSSA). Quebec follows the Régie du bâtiment du Québec (RBQ). The specific body changes by province, but the principle does not: if a contractor cannot hand you a current wallet card or direct you to verify their licence online through the provincial authority's public registry, walk away. Licensing is not optional — it is the law.

Insurance matters just as much. A legitimate residential HVAC contractor carries two types: Commercial General Liability (CGL) insurance — typically a minimum of $2 million coverage — and WSIB (Workplace Safety and Insurance Board) or WCB coverage for their workers. CGL protects your home if a technician floods your basement while rerouting a condensate line or damages your structure. WCB/WSIB protects you from liability if a worker is injured on your property. Ask for Certificates of Insurance dated for the current policy year, and call the insurer to verify they are still active. A contractor who hesitates to provide these documents has told you everything you need to know.

• Request their provincial licence number and verify it on the regulator's public registry
• Confirm CGL insurance of at least $2 million and current WSIB/WCB clearance
• Check that the licence class covers residential gas work, not just commercial

Question 2: Will You Pull the Required Permits?

In virtually every Canadian municipality, replacing a furnace requires a mechanical permit. This is not bureaucratic friction — it is the mechanism by which an independent municipal inspector verifies that the installation meets the current edition of the National Building Code of Canada and provincial amendments. Natural Resources Canada and provincial energy authorities have progressively tightened minimum efficiency standards; permits ensure compliance. When a contractor says they 'don't bother with permits to save you the paperwork,' what they are actually doing is saving themselves accountability while exposing you to serious risk. If your home ever sells, a home inspector or real estate lawyer will find unpermitted mechanical work and it will either kill the deal or land entirely on your shoulders to remediate.

The permit fee itself is modest — typically $100 to $350 in most Ontario, BC, and Alberta municipalities for a residential furnace swap. The contractor should include this in their quote or list it as a pass-through. After the installation is complete, the inspector will visit to check things like proper venting clearances, gas line connections, combustion air supply, and correct bonding of the gas line. A contractor who welcomes inspections is confident in their work. One who discourages permits is not. Always ask: 'Will you pull the permit, and will you be on site for the final inspection?'

Question 3: What Size Furnace Are You Recommending, and How Did You Calculate It?

This question alone separates the professionals from the guessers. The correct way to size a furnace is through a Manual J load calculation — a methodical heat-loss analysis that accounts for your home's square footage, ceiling height, insulation values (expressed as R-values), window area and orientation, local design temperatures (how cold it actually gets in your climate zone), and infiltration rate. Natural Resources Canada's HOT2000 software is widely used by Canadian energy auditors for exactly this purpose. A contractor who quotes you a furnace based solely on what was there before, or on a simple square-footage rule of thumb, is taking a shortcut that will cost you comfort and money.

Oversizing is the more common error in Canada, driven partly by the cultural instinct to 'never be cold.' An oversized furnace short-cycles — it heats the space quickly, shuts off, and fires again repeatedly. This creates cold spots, excess humidity fluctuation, premature heat exchanger fatigue, and higher fuel consumption. Undersizing leaves you cold on the coldest design days. The right answer is a furnace sized to your home's actual calculated heat loss at design temperature, typically expressed in BTUs per hour. Use our furnace size calculator and BTU calculator to arrive at a reasonable ballpark before the contractor arrives, so you can evaluate their recommendation with real context.

• Ask for a written Manual J or equivalent heat-loss calculation
• Be skeptical of any sizing based only on the previous furnace's capacity or rough square footage
• Compare the contractor's recommendation against your own estimate using a sizing calculator

Question 4: What AFUE Rating Are You Recommending and Why?

Annual Fuel Utilization Efficiency (AFUE) is the standardized measure of how efficiently a furnace converts fuel to usable heat over a heating season. A 96% AFUE furnace converts 96 cents of every dollar of gas into heat; the remaining 4 cents exits through the flue. As of 2023, Canada's minimum AFUE standard for new gas furnaces in most regions is 92%, a meaningful jump from the old 78% floor. High-efficiency condensing furnaces typically run 95% to 98% AFUE and use a secondary heat exchanger to recover heat from combustion gases that a conventional furnace simply exhausts. They vent through PVC pipe rather than a metal chimney, which has its own installation implications.

The efficiency decision is a financial one as much as a comfort one. A homeowner in Saskatchewan spending $2,400 per year on natural gas with a 78% AFUE furnace could reasonably expect to drop that bill to around $1,600 to $1,700 with a 96% AFUE replacement — a savings of $700 or more annually. Payback periods on the higher upfront cost of a high-efficiency model typically run three to seven years in cold Canadian climates, making them the right economic choice for most homeowners planning to stay in their home. Use the efficiency savings calculator to model your specific numbers. A good contractor should be able to walk you through this math on the spot and explain why they are recommending a specific AFUE tier for your home.

Question 5: Does This Installation Qualify for Government Rebates, and Will You Help Me Claim Them?

Canada has a layered rebate ecosystem for high-efficiency heating equipment. At the federal level, the Canada Greener Homes Grant and its successors have offered up to $5,000 for qualifying upgrades, with furnace replacements typically eligible when replacing equipment below a specified efficiency threshold. Provincial programs add another layer: Alberta's Energy Savings Rebate program, BC Hydro and FortisBC rebates, Ontario's Enbridge Gas rebates, and similar programs across Nova Scotia, Manitoba, and other provinces can each contribute hundreds of dollars toward the cost of a qualifying furnace. These programs change year to year, so verify current eligibility with the relevant provincial utility or Natural Resources Canada's energy efficiency program page.

There is a critical procedural detail that many homeowners miss: most rebate programs require a pre-approval or an energy audit before the installation takes place, not after. If you install first and apply second, you may be disqualified entirely. A knowledgeable contractor should be able to tell you which programs are currently active in your province, which equipment models on their quote qualify, and what documentation you will need — including the model number, AFUE rating, and installation date on the final invoice. If your contractor has no idea what rebate programs exist in your province, that is a gap in their professional knowledge that should give you pause.

• Ask whether the specific model qualifies for federal Canada Greener Homes or provincial utility rebates
• Confirm whether pre-installation approval or an energy audit is required before work begins
• Request that the final invoice include all details required for rebate claims: model, serial number, AFUE, and installation date

Question 6: What Does the Warranty Cover and Who Is Responsible for It?

Furnace warranties operate on two distinct levels that homeowners frequently confuse. The manufacturer's warranty covers the equipment itself — typically a limited lifetime or 20-year warranty on the heat exchanger, and five to ten years on parts, depending on the brand. Brands like Lennox, Carrier, Trane, Goodman, York, and Rheem each structure their warranty terms differently, and most require product registration within 30 to 60 days of installation to activate the full term. If your contractor fails to register the equipment or installs it without pulling permits — which some manufacturers treat as a warranty condition — you may find your warranty voided before the furnace sees its first winter.

The second warranty layer is the installer's labour warranty — the contractor's own guarantee on the quality of their workmanship. This is separate from the manufacturer's warranty and varies widely: legitimate residential contractors typically offer one to five years on labour. Get this in writing. Understand what it covers: does it include return trips to adjust gas pressure, verify combustion readings, and balance airflow? Does it exclude pre-existing ductwork deficiencies? A comprehensive written warranty on labour is a contractor's statement of confidence in their own work. A vague verbal assurance is not binding and worth nothing when you are standing in a cold house in February arguing over who is responsible.

Question 7: What Will You Do With My Existing Ductwork and Venting?

A new furnace dropped into an old duct system is one of the most common sources of post-installation problems in Canada. Older homes — particularly those built before 1990 — often have ductwork sized for lower-efficiency, higher-temperature furnaces that ran supply air at 60°C to 70°C. Modern high-efficiency furnaces run cooler, around 40°C to 55°C, and move more air volume to compensate. If the duct system is undersized or leaky, the new furnace will struggle to distribute heat evenly, fan noise will increase, and the equipment will cycle more than it should. Ask the contractor whether they intend to measure static pressure in the duct system and whether they will seal accessible duct joints.

Venting is the other critical area. If you are upgrading from a conventional 80% AFUE furnace to a high-efficiency condensing unit, the existing metal flue chimney cannot be reused — condensing furnaces produce acidic flue gases at low temperatures that will quickly corrode metal venting. They require 2-inch or 3-inch PVC intake and exhaust pipes that typically terminate through the side of the home. The location of these penetrations matters: they must be a minimum distance from gas meters, electrical panels, windows, and property lines as specified in the National Building Code and provincial amendments. A contractor who does not raise venting as a topic during the quoting process either is not proposing a high-efficiency unit or is not thinking carefully about the full scope of the job.

Question 8: Who Will Actually Do the Work, and What Are Their Qualifications?

This question trips up more homeowners than almost any other. A company can be licensed, insured, and reputable at the ownership level — and still send an unlicensed apprentice to do unsupervised gas work at your home. Under most provincial gas safety regulations, gas connections must be made by or under the direct supervision of a licensed gas fitter. 'Direct supervision' has a specific legal meaning: the licensed tradesperson must be on site, not answering a phone in a truck two streets over. Ask the contractor explicitly: 'Who will be doing the gas connections, and do they hold a current provincial gas fitter licence?' Then ask to see that person's licence, not just the company's.

On larger jobs involving both mechanical and electrical work — which most high-efficiency furnace installations require, since a new furnace often needs a new dedicated circuit or a thermostat wiring update — you may also have an electrician involved. Confirm that any electrical work is performed by a licensed electrician and that the appropriate electrical permit is pulled separately if required by your municipality. Understanding exactly who will be in your home, what their qualifications are, and who is responsible for what scope of the job is not paranoia — it is due diligence on a job that involves your family's safety.

• Ask for the name and licence number of the gas fitter who will physically make the gas connections
• Confirm that supervision requirements under your provincial gas safety code will be met
• Verify that any electrical scope is handled by a licensed electrician under a separate electrical permit

Question 9: What Is Your Commissioning and Testing Process After Installation?

Installation ends when the furnace fires. Commissioning ends when it is verified to run correctly, safely, and efficiently. These are two very different endpoints. A properly commissioned residential furnace installation includes measuring gas inlet and manifold pressure with a manometer and comparing them to the manufacturer's specifications, verifying combustion using a combustion analyzer (measuring CO, CO₂, O₂, and flue gas temperature), confirming that static pressure in the duct system falls within the furnace's rated range, checking that all safety switches — limit switch, pressure switches, rollout switch — operate correctly, and confirming that the thermostat is wired and calibrated properly.

Carbon monoxide testing is non-negotiable. A cracked or improperly sealed heat exchanger, a negative-pressure building condition that causes flue gas backdrafting, or an incorrectly adjusted burner can produce CO at levels that are dangerous well before they are detectable by occupants. Ask the contractor whether they will test for CO at the supply registers and at the flue outlet as part of their commissioning procedure. Ask for a written commissioning report — some contractors provide a standard form. If the contractor's idea of commissioning is 'we turned it on and it was heating,' that is not commissioning. That is a test fire, and it is not sufficient.

Question 10: What Does the Full Written Quote Include, and What Could Change It?

A professional furnace installation quote should be in writing and should itemize, at minimum: the make, model, and AFUE of the furnace; any additional components included (thermostat, condensate pump, humidifier, filter system); the scope of ductwork modifications; the venting method and materials; permit fees; haul-away of the old unit; and a clear statement of what is and is not included. Quotes that simply say 'furnace installation — $X' are not quotes in any meaningful sense. They are a number with no basis for accountability. When a surprise arises — and on older homes, surprises often do — a vague quote gives the contractor enormous latitude to add charges that were never discussed.

Ask specifically what could cause the final price to differ from the quoted price. Legitimate change-order scenarios include discovery of undersized gas line that requires upgrading, asbestos on old duct connections that triggers legal abatement requirements, or code-non-compliant electrical that must be brought up to standard before a permit can close. These are real, and an honest contractor will flag the possibility upfront. What is not legitimate is a contractor who uses a low quote to win the job and then invents add-ons once the old furnace is already out. Get a clear change-order process in writing: any scope change above a defined dollar threshold requires written authorization from you before work proceeds. If the contractor balks at this, they have revealed their business model.

• Require a fully itemized written quote with make, model, AFUE, scope, and permit fees listed separately
• Ask for a written change-order process before work begins
• Confirm haul-away of the old unit is included — in most provinces this is a regulatory requirement
• Request a completion checklist or commissioning report as a contract deliverable

Putting It All Together: How to Compare Multiple Quotes

Get a minimum of three written quotes for any furnace installation. This is not about driving the price to the floor — it is about having enough data points to identify the outliers in both directions. A quote that is dramatically lower than the others usually signals that something is missing: the permit, the commissioning step, the proper venting materials, or qualified labour. A quote that is dramatically higher is not automatically better. What you are looking for is a cluster of credible quotes from licensed, insured contractors who have answered all ten questions above to your satisfaction. Within that cluster, price becomes a legitimate differentiator.

Use the tools available to you. Run the furnace size calculator before anyone arrives so you understand the load range you are working with. Review high-efficiency furnace models to understand the efficiency and feature tiers available. Compare financing options if the upfront cost is a constraint — many provinces have utility-backed financing programs at low interest rates for high-efficiency equipment that can make a better furnace accessible without a large cash outlay. The best installation is one where a qualified professional installs the right-sized, properly efficient furnace, documented and permitted, with a written warranty on both parts and labour. That outcome starts with the questions you ask before you sign.