A gas furnace that is working properly is a safe appliance. It burns fuel, sends the exhaust outside and moves warm air through the house. Carbon monoxide only becomes a concern when something in that chain goes wrong: the burn is poor, the exhaust cannot get out, or the heat exchanger that separates the flame from your air has failed.
This guide covers what carbon monoxide is, where Ontario requires alarms, what to do if one sounds, and how the different kinds of houses in Binbrook tend to carry different risks. Most of it is steady, routine knowledge. A few parts are direct, because they need to be.
Carbon monoxide is a by-product of burning fuel
Carbon monoxide, or CO, is a gas you cannot see, smell or taste. Any appliance that burns natural gas or propane makes some of it. In a healthy system, that small amount leaves through the vent with the rest of the exhaust.
Problems start when combustion is incomplete or the exhaust has nowhere to go. A blocked vent, a chimney that no longer drafts, a dirty burner or a cracked heat exchanger can all let CO build up indoors. Furnaces are not the only source. Gas water heaters, fireplaces, ranges, dryers and a car idling in an attached garage can all contribute.
Early exposure feels a lot like the flu: headache, dizziness, nausea, tiredness and confusion. A useful pattern to notice is that symptoms ease when people leave the house and return when they come back, or that several people in the home feel unwell at the same time without a fever.
Ontario requires an alarm next to each sleeping area
The Ontario Fire Code requires a working carbon monoxide alarm next to each sleeping area in a home that has a fuel-burning appliance, a fireplace or an attached garage. If you heat with a gas furnace, that rule applies to you.
In practice, that means:
- An alarm in the hallway outside the bedrooms, close enough that it will wake people who are asleep.
- If bedrooms are spread across different floors or ends of the house, an alarm near each group of bedrooms.
- Alarms placed and mounted the way the manufacturer's instructions describe, since some are meant for the wall and some for the ceiling.
Many households also add an alarm on each storey, including the basement where the furnace sits. That goes beyond the minimum, but it gives earlier warning if a problem starts near the appliance. Keep a basement alarm a short distance away from the furnace and water heater rather than right beside them, and follow the spacing the manufacturer gives.
A few habits keep alarms doing their job:
- Press the test button once a month.
- Replace batteries on the schedule the manufacturer suggests, or when the alarm chirps.
- Check the replacement date printed on the back. CO alarms wear out, and the sensor stops being reliable after its rated life.
- Do not paint over an alarm or tuck it behind curtains or furniture.
Combination smoke and CO alarms are fine, as long as there is one in each place the Fire Code requires.
If the CO alarm goes off, leave first
This is the one part of the guide to treat as firm. If a carbon monoxide alarm sounds, or if anyone in the house has symptoms that fit, get everyone outside, including pets. Do not stop to look for the source.
Once you are outside, call emergency services. If you also suspect a gas leak, call your gas supplier's emergency line from outside. Stay out until responders tell you the house is clear.
After that, the furnace and any other gas appliances should stay off until a gas technician has inspected them. Do not reset the furnace and hope the alarm was a fluke. The alarm may well be right.
If the alarm is chirping rather than sounding a full alarm, it is usually a low battery or an end-of-life warning. The pattern differs by model, so check the label or the instructions to tell the two apart.
Binbrook's houses carry different risks
Binbrook has three broad kinds of houses, and each tends to have its own venting story.
**The village core along Highway 56 and Binbrook Road.** The oldest houses here were often built for oil or coal and converted to gas later. A technician may find an old chimney that was never relined, or ducts that were never resized. An unlined masonry chimney can crumble inside, cool the exhaust too much and stop drafting properly, which can push combustion gases back into the house.
**Mid-century houses along Binbrook Road.** These usually have mid-efficiency gas furnaces that vent through a chimney. Many are near the end of their life. Worn heat exchangers and venting that is the wrong size for the furnace are common findings. A cracked heat exchanger is a fault that should not be left running, because it can let combustion gases, including CO, into the air the furnace circulates. For more on age and wear, see how long a furnace lasts.
**Newer subdivisions around Fall Fair Way, Fletcher Road and Royal Winter Blvd.** These homes usually have high-efficiency condensing furnaces that vent through the side wall with plastic pipe. The furnace is designed to shut itself off if the vent is blocked, but a drift or ice over the pipes is still worth clearing promptly. Winters up on the Mountain bring regular snow, and side-wall vents sit low enough to get buried.
What is safe to check yourself
Some things are well within reach of any homeowner:
- Look at the side-wall vent pipes outside after a snowfall and clear snow or ice away by hand.
- Keep the area around the furnace and water heater clear of storage, laundry and anything that blocks airflow.
- Change the furnace filter on schedule.
- Watch the burner flame through the viewing window if your furnace has one. A steady blue flame is normal. A lazy, yellow or flickering flame is a reason to book a visit.
- Notice soot, rust or water staining near the furnace, the vent connector or the chimney base.
- Never run a car, generator or barbecue inside a garage or the house.
What to leave to a technician
Opening the furnace cabinet, inspecting the heat exchanger, testing combustion and checking chimney draft are jobs for a gas technician. In Ontario, gas appliances must be installed, serviced and repaired by a registered gas contractor's technicians under Ontario Regulation 212/01, and installations follow the CSA B149.1 Natural Gas and Propane Installation Code. That rule exists for good reason, and it also keeps manufacturer warranty terms intact.
An annual inspection is the most practical defence. A technician can check the venting, measure combustion, look for cracks and confirm the chimney is drafting. Catching a worn part early usually costs far less, and causes far less worry, than a mid-winter shutdown. If your furnace has also been blowing cold air or cycling oddly, our guide on why a furnace blows cold air may help, and the FAQ covers other common questions.
Work is performed by TSSA-certified gas technicians.
If you would like your venting and heat exchanger checked before the cold settles in, book a furnace and AC maintenance visit with Binbrook Furnace Repair.