A furnace rarely fails all at once. It usually slows down first. It takes longer to warm the house, it needs a repair one winter and another the next, and it gets a little louder each season. If you are wondering whether yours is wearing out, you are probably noticing some of that. This guide explains how long furnaces tend to last, which signs matter, and how to decide calmly whether to repair or replace.
A furnace has no fixed expiry date
A well-kept gas furnace usually gives many winters of service, often more than people expect. There is no single number that applies to every house. Two furnaces of the same age can be in very different shape, depending on how they were installed, how often they were serviced and how hard they have had to work.
A few things shorten a furnace's life:
- A unit that is too big for the house, so it turns on and off in short bursts instead of running steady cycles.
- Ducts that are too small or too restrictive, so the furnace runs hot.
- Filters left in too long, which starves the furnace of air.
- Venting that is the wrong size for the furnace, or a drain that keeps backing up.
- Years without a seasonal check.
The age is still worth knowing. You can usually find the manufacture date on the rating plate inside the furnace door, or work it out from the serial number. Your technician can read it for you on the next visit.
What your house says about your furnace
Binbrook has three broad kinds of houses, and each tends to wear its furnace out in its own way.
In the old village core along Highway 56 and Binbrook Road, many houses were built for oil or coal and later converted to gas. A technician may find a chimney that was never relined, ducts that are too small for a modern furnace, or an old oil tank left in place. In these houses the furnace is often only part of the picture. The chimney and ducts decide how well any new unit will work.
The older detached houses further along Binbrook Road usually have mid-efficiency gas furnaces vented through a chimney. Many of these are now near the end of their life. The usual findings are worn heat exchangers, venting that does not suit the furnace, and old ductwork.
The newer subdivisions and townhouses around Fall Fair Way, Fletcher Road, Royal Winter Blvd, Binhaven Blvd and Reid Ave N mostly have high-efficiency condensing furnaces that vent through the side wall with plastic pipe. These are younger systems, but the first ones put in by builders are getting older. Common calls here are blocked condensate drains and units that are larger than a tight modern house needs. An oversized furnace short cycles, and short cycling wears parts out sooner.
Signs a furnace is wearing out
None of these signs on its own means you need a new furnace. Together, and in an older unit, they are worth taking seriously.
- Repairs are becoming regular. One repair is normal. A new part every winter is a pattern.
- Rooms heat unevenly, or the house takes noticeably longer to warm up than it used to.
- Your gas use is creeping up while the way you live has not changed.
- The furnace turns on and off often, in short runs.
- New noises: rattling, banging on start-up, or a blower that sounds strained.
- Rust, water or scaling around the furnace cabinet or at the base of the vent.
- The burner flame looks lazy or uneven, or there is soot around the burner area.
- Parts for your model are getting hard to find.
It helps to compare against the weather, not against last week. Environment and Climate Change Canada publishes climate normals for the Hamilton airport station, up on the Mountain near Binbrook and Mount Hope. That is the local reference for how cold a typical winter gets here, and it is a fair way to judge whether a furnace that struggles is struggling in ordinary weather or in an unusual cold snap.
The two signs not to wait on
Most wear is gradual and can be planned for. Two things cannot.
A cracked heat exchanger can let combustion gases, including carbon monoxide, into the air the furnace moves through your house. If a technician finds one, the furnace should not be run. This is the most common reason an older furnace is replaced rather than repaired.
If your carbon monoxide alarm sounds, or anyone in the house has headaches, dizziness or nausea that ease when they go outside, leave the house and call for help from outside. Do not try to find the cause yourself. The Ontario Fire Code requires a working carbon monoxide alarm next to each sleeping area in a home with a fuel-burning appliance, a fireplace or an attached garage. Test yours, and replace them when they reach the end of the life printed on the unit. Our guide to carbon monoxide and gas furnaces has more.
What is safe to check yourself
You can do a few things without opening the furnace:
- Change or check the filter, and note how quickly it gets dirty.
- Look at the rating plate for the age and model.
- Keep supply and return grilles clear of furniture and rugs.
- In a newer house, keep the side-wall vent pipes clear of snow and ice, and watch for water around the condensate drain.
- Keep a simple list of repairs and dates. It makes the repair-or-replace decision much clearer.
Leave everything inside the cabinet to a technician. In Ontario, gas appliances must be installed, serviced and repaired by a contractor registered with the TSSA, using certified gas technicians, under Ontario Regulation 212/01, and installations follow the CSA B149.1 Natural Gas and Propane Installation Code. With Binbrook Furnace Repair, work is performed by TSSA-certified gas technicians.
Weighing a repair against a replacement
There is no formula, but a few plain questions help.
- How old is the furnace, and how much life is it likely to have left?
- How does the repair cost compare with the cost of a new unit? A small repair on a younger furnace is usually worth doing. A large repair on an old one often is not.
- Is this the first repair in a while, or the third in a few winters?
- Is the heat exchanger sound?
- Is the furnace the right size for the house as it is now, after new windows, insulation or an addition?
Ask for both numbers in writing: the repair and a replacement. With both in front of you, the decision is usually easier than it feels on a cold night. If the furnace is still sound, a repair and a seasonal maintenance visit may carry it through several more winters. Regular service also helps keep the manufacturer's warranty terms met on newer units, so keep your records.
If replacement is the answer
A new furnace should be sized to the house, not copied from the old label. A tight new townhouse often needs a smaller unit than the builder put in. An older core house may need the chimney lined or the ducts changed before a new furnace will work well, and when a high-efficiency furnace vents through the wall, a gas water heater left alone in an old chimney may not draft properly. Ask about all of this before you choose. Some households also look at a heat pump or a hybrid system at this point, and it is worth asking which rebate programs are current.
If you would like a clear look at where your furnace stands, see our furnace installation and replacement service.