Carbon Monoxide Alarms

Carbon monoxide (CO) is a poisonous gas that you can't see, smell, or taste. Over 65 per cent of all deaths and injuries from CO occur in homes.

As of January 1, 2026, Ontario Fire Code changes require:

  • A CO alarm adjacent to every sleeping area in your home.
  • A CO alarm on every storey of your home that does not contain a sleeping area (for example, a main floor or basement).

Even if your home already has CO alarms, you may need to add more to comply with the updated Fire Code. For added protection, combination smoke/CO alarms on each level can be used.

Using Fuel-Burning Appliances Safely

Never use outdoor fuel-burning appliances, such as barbeques, camping stoves, or propane heaters, indoors. Only use them outdoors.

Know What to Do

A working CO alarm gives warning if dangerous levels of CO are present. If the alarm goes off, or if anyone shows symptoms of CO poisoning, leave your home immediately and call 9-1-1.

Symptoms may include:

  • Confusion
  • Dizziness
  • Headaches
  • Nausea
  • Shortness of breath

Maintain Your Fuel-Burning Appliances

Have all fuel-burning appliances and vents inspected annually by a licensed contractor. Common CO sources include:

  • Fireplaces
  • Furnaces
  • Gas dryers
  • Portable fuel heaters
  • Stoves
  • Water heaters
  • Solid fuel-burning appliances (e.g., wood stoves)

Testing and Replacing CO Alarms

Test CO alarms monthly and replace batteries at least once a year. Replace alarms according to manufacturer recommendations (typically every 5–10 years).

Landlords and Tenants

Landlords must install and maintain working CO alarms in rental properties and provide maintenance instructions to tenants. They must also test alarms annually and replace batteries as needed. Tenants must report (in writing) any non-functioning CO alarms. Removing batteries or tampering with detectors is against the law.