Furnace installation and replacement in Ottawa

Walk into a basement in Centretown, the Glebe or Sandy Hill and the furnace is usually too big for the house. These homes were built for coal or wood, had ducts threaded through them decades later, and the furnace was picked with a generous safety margin that nobody has questioned since. The bungalows and split-levels of Alta Vista, Carlington and Bells Corners have often had the furnace swapped like-for-like two or three times, carrying the original mistake forward each time.

An oversized furnace runs in short bursts: full fire, thermostat satisfied, off, repeat. The far bedrooms never warm through, the gas bill is higher than it should be, and igniters and blowers wear out early. So the first thing we do on any replacement is a heat-loss calculation for the actual house: floor area, insulation, windows, ceiling heights, which way it faces. The second is a look at whether the ductwork can carry the airflow the new furnace needs, and whether it should be sealed or rebalanced first. The size and model come after that, not before.

The subdivisions that went up from the 1980s to the 2010s were fitted with whatever furnace the builder bought by the hundred. Many of those units are now between fifteen and thirty years old, and a good share of the original ones are 80 percent mid-efficiency models that cost noticeably more to run than a modern condensing furnace. If yours is in that bracket, replacing it on a date you choose in the fall is cheaper and far less stressful than replacing it after it quits on a January night; how long a furnace lasts explains what to watch for.

Every furnace we install is a condensing unit at 95 percent AFUE or better, which keeps roughly one more dollar in five on the heating portion of an Enbridge bill compared with the mid-efficiency furnaces of the 1990s. The choice is really about how the furnace behaves. A single-stage furnace is either on at full output or off. A two-stage furnace spends most of the winter at a lower fire and steps up for the cold snaps. A modulating furnace with a variable-speed blower adjusts in small increments and runs almost continuously on cold days, which gives the steadiest temperatures and the quietest operation of the three.

In Ottawa the second and third options earn their keep: the shoulder seasons are long, and the difference between a mild December day and a -30 night with wind chill is wide enough that a furnace able to vary its output is more comfortable and uses less gas. That said, a single-stage furnace is still the right call for plenty of smaller houses, and we say so when it is. Ask which makes are carried when you call.

For an ordinary Ottawa house in 2026, a 96 percent single-stage furnace typically costs $4,800 to $6,300 installed, a two-stage model $5,800 to $7,800, and a modulating furnace with a variable-speed blower $7,400 to $9,900. The things that push a job toward the top of a range are the furnace size, venting that has to be rerouted, a gas line that needs upsizing, old sheet metal that must be rebuilt, and the thermostat you pick. The written quote is the installed price; nothing is added on the day.

A straightforward replacement is done in one working day. For a fuller breakdown, see what a new furnace costs in Ontario, and if you are weighing a repair against a new unit, repair or replace.

The old furnace comes out and is hauled away. New intake and exhaust venting is run to code, with the terminations placed where Ottawa snow will not bury them. A condensate drain is fitted, with a neutralizer where the drain requires one. Plenum and transition sheet metal is made to fit the new cabinet. The gas line, shutoff valve and drip leg are checked and replaced where needed. The thermostat is wired and tested, or a new one fitted. Before we leave, the furnace is set up with a combustion analyzer and run through a full start-up test, and any inspection the TSSA or the City of Ottawa requires is arranged.

Ontario law requires that gas appliances be installed by technicians certified by the Technical Standards and Safety Authority and that the work meet the Ontario Gas Utilization Code; both apply to every furnace we fit. The manufacturer warranty is registered for you. Ask about the labour warranty and about a maintenance plan when you book, since most manufacturers tie the parts warranty to annual service.

Ottawa homeowners have three programs worth asking about: the Enbridge Home Efficiency Rebate Plus program, which needs an NRCan-registered energy audit before and after the work; the Canada Greener Homes Loan, an interest-free loan for qualifying retrofits; and the City of Ottawa Better Homes Ottawa loan program, which is repaid through the property tax bill. None of them is aimed at a gas furnace on its own. Pair the furnace with a cold-climate heat pump as a hybrid system and the picture changes, and you get air conditioning out of the same outdoor unit.

The programs open, close and change their rules through the year, so we check what applies at the time of the quote, tell you the sequence (audit first, then install, then the second audit) and handle the forms. Financing for the furnace itself is available on request; ask when you call. The rebates guide tracks what is currently open.