Most people think about the furnace only when it stops. Maintenance is the quieter side of that: an unhurried look at the system on a mild day, so that worn parts are found before a cold night finds them for you. This guide explains what a proper tune-up covers, how often to book one, and which small jobs are yours to do in between.
How often should a furnace be serviced?
For a gas furnace, once a year is the usual advice, and most manufacturers write something similar into their warranty terms. Late summer or early autumn is a sensible time: the furnace has not been working hard, and a part that needs ordering can arrive before the heating season.
If you have central air, the furnace blower and cabinet serve both systems, so many households book one visit that covers heating and cooling together. A heat pump works in both seasons and benefits from the same yearly attention.
A few situations call for a look sooner:
- The furnace is making a new noise, such as a rattle, squeal or a bang on start-up.
- It starts and stops much more often than it used to.
- Some rooms have become noticeably colder than others.
- You have just bought the house and do not know when it was last serviced.
- Your carbon monoxide alarm has sounded, even once.
Why does maintenance matter for the warranty?
Many manufacturers' warranties on furnaces and their parts expect regular professional maintenance, and some ask for proof of it if a claim is made. Keep the invoice or service record from each visit in one folder with the furnace manual. If a heat exchanger or control board fails while the unit is still under the manufacturer's warranty, those records can make the difference between a covered part and one you pay for. Read your own warranty paperwork, since the terms differ from one manufacturer to another.
What does a furnace tune-up actually cover?
A thorough tune-up is part cleaning, part testing and part inspection. The details depend on the furnace, but a good visit generally includes the following.
- Checking and cleaning the burners so the flame is steady and even.
- Cleaning the flame sensor, a small rod that tells the furnace the burner has lit. A coated sensor is one of the most common reasons a furnace lights and then shuts off.
- Inspecting the igniter for cracks or wear.
- Checking the heat exchanger for cracks, rust or signs of overheating.
- Testing the inducer motor, which pushes exhaust out through the vent, and listening for worn bearings.
- Checking the pressure switch and the small hoses connected to it.
- Testing the safety controls, including the high-limit switch that shuts the furnace down if it overheats.
- Measuring gas pressure and checking the burner is getting the right amount of gas.
- Inspecting the blower motor and wheel, and cleaning dust off the wheel where it has built up.
- Checking the venting from the furnace to the outside for leaks, sagging runs or blockages.
- On high-efficiency furnaces, flushing or checking the condensate drain, trap and pump.
- Checking the thermostat is calling for heat correctly and the furnace responds.
- Replacing or checking the filter.
At the end you should be told plainly what was found, what is fine, and what is wearing. A part that is wearing is not always a part that needs replacing today. The useful thing is knowing about it, so you can plan rather than react.
Natural gas and propane appliances in Ontario are installed and serviced to the CSA B149.1 Natural Gas and Propane Installation Code, and a tune-up is a good moment to have the venting and gas connections looked at against that standard.
What does maintenance look like in different Stoney Creek houses?
The furnace in your basement depends a lot on when the house was built, and so does what a technician tends to watch for.
### Older houses in Olde Towne, along King Street and Lake Avenue
Houses from the 1800s and early 1900s were first heated by wood or coal and converted later, sometimes to hot-water radiators, sometimes to ductwork added after the fact. Maintenance here often means paying attention to things around the furnace as much as the furnace itself: undersized or oddly routed ducts, an ageing boiler, and an old chimney. When a house moves to a high-efficiency furnace vented through the wall, the old chimney can be left with no appliance or with only a water heater, and it is worth having that venting checked. Some of these properties also still have an old oil tank that was never removed, which is worth mentioning when the technician is there.
### The 1990s and 2000s subdivisions on the mountain
In Felker, East Felker and Heritage Green, most houses have a forced-air gas furnace with central air, and many of those original units are now near the end of their life. This is where yearly maintenance earns its keep. Inducer motors start to wear, control boards begin to fail, heat exchangers show their age, and the air conditioner is often due for replacement too. A tune-up will not make an old furnace young, but it can catch a noisy inducer or a cracking heat exchanger before it leaves you without heat in January. If several of these show up at once, the guide on which furnace repairs are the big ones can help you weigh what comes next.
### Newer homes in Fruitland and Winona
Newer houses usually have high-efficiency condensing furnaces with plastic venting, central air and an HRV or ERV for ventilation. The furnace itself is young, but the common problems are easy to miss: condensate drains that block or freeze, wall vents covered by snow, and ventilation units that have never been maintained since the family moved in. Ask for the HRV or ERV to be included in the visit; its filters and core need cleaning too.
### Rural properties above the escarpment
Much of Stoney Creek is still farmland, and some rural homes are not on a natural gas main. They may heat with propane or oil, and the maintenance differs with the fuel. Confirm which one you have when you book so the right parts and checks are planned.
What can you safely do yourself between visits?
A few jobs are yours, and they make a real difference.
- Check the filter monthly during the heating season and change it when it looks grey or clogged. A blocked filter is one of the most common reasons a furnace overheats and shuts down.
- Keep the area around the furnace clear of boxes, laundry and anything that burns.
- On a high-efficiency furnace, keep the two plastic pipes outside clear of snow, ice and leaves.
- Make sure supply and return vents in each room are open and not covered by furniture.
- Test your carbon monoxide alarms. The Ontario Fire Code requires a working carbon monoxide alarm next to each sleeping area of a home with a fuel-burning appliance, a fireplace or an attached garage.
What is not safe to do yourself: opening the burner compartment, adjusting the gas valve, disconnecting venting, or repeatedly resetting a furnace that keeps shutting off. Those are signs something needs a proper diagnosis. If the furnace will not start at all, the guide on why a furnace won't turn on and whether it is safe to reset it explains what to look at first.
Is maintenance worth it on an older furnace?
In general terms, a yearly visit costs a small fraction of a major repair or an unplanned replacement in the middle of winter. On an older furnace, its main value is information: you learn which parts are wearing and roughly how much life is left, so a replacement can be a considered decision made in the autumn rather than a rushed one made on a cold night.
Work is performed by TSSA-certified gas technicians. If your furnace is due for its yearly visit, see furnace and AC maintenance.