What usually goes wrong
Ottawa adds a fault of its own to the usual list: on the coldest nights the exhaust from a high-efficiency furnace can freeze at the outside wall, and a snowdrift or an icicle over the intake will trip the pressure switch and shut the furnace down. Clear the pipes and it often restarts. After that, the common failures are the same as anywhere: a hot-surface igniter that has cracked, a flame sensor so coated it cannot prove a flame, a blocked condensate trap, a high-limit switch tripping because a clogged filter or a tired blower is letting the heat exchanger overheat, and control boards that have simply reached the end.
The symptom tells us where to start. A furnace that will not come on at all points one way; one that lights and shuts off a minute later points another; cold air from the registers a third. Bangs on start-up, a smell of burning dust that does not clear, constant cycling and a thermostat that does nothing all have short lists of causes. We test through the list instead of swapping parts until something works.
Repair prices in Ottawa
A diagnostic visit in the Ottawa area is typically $109 to $159 in 2026 and is credited toward the repair if you go ahead. Typical repair prices, parts and labour together: hot-surface igniter $220 to $380; flame sensor $160 to $270; blower capacitor $160 to $260; pressure switch $220 to $370; inducer motor $480 to $850; blower motor $550 to $1,000, with variable-speed ECM motors above that; control board $480 to $900. These are typical ranges; the exact figure for your furnace is written down before any part is fitted, and if a part has to be ordered you are told the lead time at the same moment.
When a repair stops making sense
A quick test we share with homeowners: multiply the age of the furnace in years by the cost of the repair. Under about $5,000, repair it. Over that, and especially past fifteen years, the money is usually better spent on a replacement. A $300 igniter on a ten-year-old furnace is an easy yes. A $900 control board on a twenty-year-old mid-efficiency unit is throwing good money after bad, and we will tell you so with both numbers in front of you. The thinking is laid out in repair or replace and how long a furnace lasts.
One fault we do not repair around: a cracked heat exchanger. Combustion gases can cross into the air the furnace sends through the house, and carbon monoxide is one of them. The furnace is shut down until it is replaced.
What happens when you call
You describe the symptom and, if the house is cold, you get the first available slot. The technician confirms the fault by testing, not by assumption, and shows you what was found. The repair price goes on paper before any work starts. The van carries the parts that fail most, so igniters, flame sensors, capacitors, pressure switches and the common control boards are usually fitted on the first visit. Every repair comes with a written warranty on the part and the labour; ask for its terms when you book.
