Is an alarm sounding now?
The Government of Ontario says to get everyone out of the home immediately and call 911 from outside the building (Government of Ontario). Read the rest later.
Which Ontario homes need a carbon monoxide alarm?
The rules differ slightly for a house and for an apartment or condo unit. Every line below is from the Government of Ontario's carbon monoxide page (Government of Ontario).
| Home | An alarm is required if |
|---|---|
| A house | It has a fuel-burning appliance, a fireplace or an attached garage, or (since January 1, 2026) it is heated by air from a fuel-burning appliance not contained within the home. |
| An apartment or condo unit | The unit has a fuel-burning appliance or a fireplace; the unit is directly above, below or beside a service room or a garage; or (since January 1, 2026) the unit is heated by air from a fuel-burning appliance outside it, such as a furnace in a building service room. |
Where do the alarms have to go?
| Location | House | Apartment or condo |
|---|---|---|
| Beside each sleeping area (the hallway outside the bedrooms) | Yes | Yes |
| Every storey, including storeys without bedrooms | Yes, since January 1, 2026 | Yes, since January 1, 2026 |
| Public corridors heated by air from a fuel-burning appliance | Not applicable | Yes, since January 1, 2026 |
So a basement with a furnace and no bedroom now needs its own alarm. Alarms may be hardwired, battery-operated or plug-in, and many units combine a smoke alarm and a carbon monoxide alarm; the two sound differently, so everyone in the home should know which is which.
Who is responsible in a rental?
The landlord installs and maintains the alarms, tests them every year, when the battery is replaced, when the electrical circuit changes and when tenants change, and gives the tenant the maintenance instructions. The tenant tells the landlord about any problem with an alarm. It is against the law for anyone to remove the batteries or tamper with an alarm (Government of Ontario).
What are the signs of carbon monoxide?
The province calls carbon monoxide an invisible, tasteless and odourless gas. Exposure can cause headaches, nausea, dizziness, confusion, drowsiness, loss of consciousness and death. It comes from fuels such as natural gas, propane, oil or wood that do not burn completely.
What do I do when the alarm sounds?
- Get everyone out of the home immediately.
- Call 911 from outside the building.
- Once the emergency services say it is safe, have the fuel-burning appliances checked before they run again. Jackman Mechanical services furnaces, boilers and water heaters: (416) 888-1371.
How do I lower the risk?
The province's own list, shortened:
- Have fuel-burning appliances, chimneys and vents cleaned and inspected by professionals every year, before cold weather sets in.
- Keep outside vents and chimneys for the dryer, furnace, stove, fireplace and other appliances clear of snow and debris.
- Use gas and charcoal barbecues outside only, away from doors, windows and vents, and never in a garage.
- Never use a stove or oven to heat your home, and open the flue before using a fireplace.
- Never run a vehicle or engine inside a garage, even with the door open.
The yearly inspection belongs to a TSSA-registered contractor with certified gas technicians, explained in who can work on gas appliances.