Fix the furnace or replace it? A decision you can make at the kitchen table

Nobody is neutral on this question. A company that would rather sell a furnace leans toward replace; one that would rather keep the service call leans toward repair. The way through is a rule you can apply yourself, at the kitchen table, with both prices in writing. This is the one we use on every call in the Ottawa area.

Three questions before any numbers

• How old is it? The date is on the rating plate inside the door, sometimes coded into the serial number. Under 12, the default is repair. Over 15, the default is to start planning. Between, it depends on the next two questions.
• What failed? A cheap wear part on a young furnace is a repair. A major component on an old one is a conversation. A cracked heat exchanger is neither; it is the end.
• What have the last two winters cost? Add it up. Two expensive repairs in two winters means the third is a deposit on a new furnace.

The repair prices beside the replacement price

Typical Ottawa-area repair prices in 2026, parts and labour, after a diagnostic of $109 to $159 that is credited against the work:

• Hot-surface igniter: $220 to $380
• Flame sensor: $160 to $270
• Capacitor: $160 to $270
• Pressure switch: $220 to $380
• Inducer motor: $480 to $850
• Blower motor: $550 to $1,000, more for a variable-speed ECM motor
• Control board: $480 to $900
• Heat exchanger: on a furnace past 12 years, replacing it is rarely worth the price, which runs to most of a new furnace

A new furnace installed: $4,800 to $6,300 for a 96 percent single-stage, $5,800 to $7,800 two-stage, $7,400 to $9,900 modulating. The full breakdown is in new furnace prices in Ottawa and Ontario. These are typical ranges; the written quote is final.

The rule, in one line: under about 12 years old and the repair is less than a third of a replacement, repair. Over 15 with a major failure, replace. In between, both numbers in writing and the gas bill in the maths.

Three Ottawa houses, three answers

• An eight-year-old builder-grade furnace in a Barrhaven two-storey stops lighting. The igniter has cracked. $300 or so, done on the first visit, and the furnace has another ten winters in it. Repair, without a second thought.
• A 17-year-old furnace in an Alta Vista bungalow, and the blower motor has seized. $800 on a unit that is already past its expected life, in a house that could use a properly sized two-stage furnace. That $800 buys a year or two at best. Replace, on a schedule you choose.
• A 22-year-old 80 percent mid-efficiency furnace in a Glebe semi, and the control board has failed and is hard to find. The furnace uses a fifth more gas than a new one every winter, and the heat exchanger has had 22 Ottawa seasons. Replace, and have the ductwork looked at on the same visit because the old unit was almost certainly oversized.

Faults that settle it on their own

• A cracked heat exchanger. Combustion gases, including carbon monoxide, can reach the air the blower sends through the house. No competent technician leaves it running, and the replacement part on an old furnace costs most of a new furnace.
• A control board or inducer on a furnace over 15 where the part is discontinued or weeks away.
• Repeated major repairs: two from the expensive half of the list above in two winters.

When the advice is wrong in both directions

A furnace is not a phone. A ten-year-old two-stage unit with a dead igniter is not out of date and has a decade left. Plenty of furnaces we are asked to replace just need a part, and we say so. Equally, a 20-year-old furnace that has been patched four times is not worth another patch because the last one was cheap. If a contractor goes straight to a replacement quote without diagnosing the fault, or refuses to quote the replacement for a furnace that is plainly at the end, get a second opinion.

The gas bill, and the heat pump question

An 80 percent furnace from the 1990s or early 2000s uses roughly a fifth more gas than a 96 percent condensing unit. Across an Ottawa heating season, which is longer than anywhere in southern Ontario, that is a few hundred dollars a year. On its own it does not pay for a furnace; added to the repairs avoided over the next five winters, it tips the borderline cases.

Replacing is also the moment to decide whether the next system is a furnace alone or a furnace paired with a cold-climate heat pump as a hybrid. The hybrid costs more up front, claims the heat pump rebates, and gives you air conditioning from the same outdoor unit. If the air conditioner is also past 12, run the numbers on both; the comparison is in heat pump or gas furnace in Ottawa.

Getting both numbers

Book a repair visit. The technician diagnoses the fault, quotes the repair in writing, and if the furnace is in the grey zone, gives you the installed price for a correctly sized replacement on the same visit, with the reasoning. The decision stays yours. The phone is answered every day of the year, and the diagnostic is credited against whichever route you take.