What happens during furnace replacement?

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The short answer: what happens on replacement day

Most residential furnace replacements in Metro Vancouver are completed in a single day by a two-person crew. The visit generally moves through five stages: shutting off gas, power, and disconnecting the old furnace; removing it and prepping the space; setting and securing the new unit; connecting gas, venting, electrical, and ductwork; then testing everything before handing the system back to you. Complex jobs — a change in furnace size, a switch from a mid-efficiency to high-efficiency model requiring new venting, or tight mechanical room access — can add time, but the core sequence stays the same.

Before the crew arrives: what you can check yourself

A few things are safe for a homeowner to confirm ahead of time and can speed up the visit. Clear a path to the mechanical room or closet so the old unit can come out and the new one can go in without squeezing past boxes or furniture. Note where your thermostat wiring runs and whether you want to keep the existing thermostat or upgrade it. If you know your home's approximate square footage and insulation quality, jot it down — it helps confirm the sizing quote. What you should not do yourself: disconnect gas lines, cap gas piping, or work on the electrical disconnect. In BC, gas work must be performed by a Technical Safety BC-licensed gas fitter, and improper handling can create a leak or carbon monoxide hazard.

Step 1: Shutdown, disconnection, and removal

The technician shuts off the gas valve, disconnects power at the furnace switch or breaker, and disconnects the old unit from the supply and return ductwork, gas line, venting, and condensate drain (if applicable). The old furnace is then removed from the mechanical closet or room. On older Metro Vancouver homes — many built before modern efficiency standards — this step sometimes reveals aging or undersized ductwork, corroded venting, or a gas line that needs updating, which the technician will point out before proceeding.

Step 2: Setting and connecting the new furnace

The new furnace is leveled and secured in place, then connected to the supply and return plenums, the gas line, electrical, and — for high-efficiency condensing models — a condensate drain line and PVC intake/exhaust venting. If you're upgrading from a mid-efficiency to a high-efficiency furnace, the venting type changes entirely (from a metal flue to sealed PVC pipe routed to an exterior wall), which is one of the bigger differences in scope between a like-for-like swap and an efficiency upgrade.

This stage is where BC code and permitting come in. Gas furnace installation and replacement in Metro Vancouver requires a permit and inspection under Technical Safety BC rules, and the work must be done by a licensed gas fitter — CANRO's technicians hold Technical Safety BC gas licence LGA0043870. A reputable contractor arranges the permit and schedules the inspection as part of the job; you shouldn't need to do this yourself.

Step 3: Testing, commissioning, and walkthrough

Before the crew leaves, they test gas pressure, verify proper venting and draft, check for combustion byproducts including carbon monoxide, cycle the system through heating stages, and confirm the thermostat communicates correctly with the new furnace. They should also check airflow at a few registers to catch any obvious duct issues. A good technician walks you through the new thermostat, points out the filter location and recommended change interval, and leaves you with warranty paperwork for both the equipment and the labour.

How long it takes and what affects the price

A straightforward same-size, same-venting-type replacement often takes 4-8 hours. Jobs that involve switching venting types, relocating the furnace, upsizing ductwork, or dealing with tight condo or townhome mechanical spaces can take longer or occasionally span two days. In Metro Vancouver, furnace installation typically runs $4,500-$9,500+ installed, before rebates, with the range driven mainly by furnace sizing, venting complexity, ductwork condition, and permit requirements rather than the furnace itself. Because every home is different, the only way to get an accurate number is a free written quote after an in-person assessment.

Rebates and financing to ask about

The Canada Greener Homes grant closed to new applicants in early 2024, so it's no longer available for a furnace project. Homeowners upgrading to a high-efficiency furnace or switching to a heat pump may still qualify for the interest-free Canada Greener Homes loan (up to $40,000), CleanBC incentives, or the Oil to Heat Pump Affordability program if replacing an oil furnace. FortisBC and BC Hydro also run rebate programs that change periodically. Ask about current program details and confirm exact figures at quote time, since amounts and eligibility shift.

Frequently asked questions

Reviewed by the CANRO Heating & Cooling service team — July 09, 2026. CANRO holds Technical Safety BC gas licence LGA0043870 and boiler licence LBP0046450, employs Red Seal certified technicians, and carries WorkSafeBC and liability insurance. 4.9★ from 85+ Google reviews · serving Metro Vancouver since 1999 · (604) 359-1081 · info@canroheat.ca.