Ontario Is Expanding CO Alarm Requirements in 2026
Starting January 1, 2026, the Ontario Fire Code will introduce important changes to where and how carbon monoxide (CO) alarms must be installed in residential properties. These updated requirements are designed to increase early detection of carbon monoxide: an invisible, odourless and tasteless gas that can be deadly without a working alarm.
Carbon monoxide is produced when fuels such as natural gas, propane, oil, wood, or gasoline don’t burn completely in appliances such as furnaces, water heaters, fireplaces, stoves, or space heaters, or when vehicles run in attached garages. Because it can’t be detected by the human senses, a properly installed CO alarm is the only reliable way to detect dangerous levels.
What the Average Home or Condo Owner Needs to Know
Under the updated Fire Code, homes with any of the following must have CO alarms installed:
- A fuel-burning appliance (e.g., furnace, water heater, gas stove)
- A fireplace
- An attached garage
- Heated air supplied from a fuel-burning appliance not located within the home (such as external boilers or outdoor furnaces)
Where alarms must be installed:
- Adjacent to every sleeping area — meaning in the hallway or common area near bedrooms
- On every storey (every floor) of the home, even floors that don’t have bedrooms
- CO alarms must meet recognized safety standards (CSA, ULC, ETL or equivalent) and be installed according to the manufacturer’s instructions.
What Landlords & Tenants Need to Know
Landlords are responsible for:
- Installing required CO alarms in all rental units that meet the criteria above
- Maintaining alarms in working order, which includes testing, replacing batteries or power sources, and replacing alarms at end of life
- Testing alarms annually and whenever there is a change in tenancy or electrical system
- Providing tenants with maintenance instructions for the CO alarms inside the unit
Ontario
Tenants are responsible for:
- Regularly test CO alarms, typically by pressing the test button each month
- Notify the landlord immediately if an alarm isn’t working, is damaged, or its operation is impaired
- Never tamper with the CO alarm in any way; this is against the law
Old Requirements vs. New Requirements
Before January 1, 2026: CO alarms were required in residential homes near all sleeping areas, only if the home had a fuel-burning appliance, a fireplace, or an attached garage. Apartment and condo rules were similar but dependent on building configuration.
After January 1, 2026: In addition to the above, CO alarms must now be installed on every storey of a home, including floors without bedrooms. This applies to single-family homes, townhomes, condos, and other residential buildings that meet the criteria. Fire Code changes also expand the scope to include homes heated with air from external fuel-burning systems.
Why These New Requirements Are in Place
Carbon monoxide poisoning continues to be a leading cause of accidental poisoning deaths in Ontario. Since CO is undetectable by human senses, the only way occupants can be alerted to dangerous levels is through properly installed and maintained alarms. The updated Fire Code aligns Ontario with more protective standards, similar to the
2020 National Fire Code of Canada, and ensures broader coverage across all floors of residential buildings. These changes will help provide earlier detection and better protection for families, renters and homeowners throughout the province.
Final Safety Reminders
- Test your CO alarms monthly
- Replace batteries annually or as recommended by the manufacturer
- Replace CO alarms according to the manufacturer’s lifespan (usually every 7-10 years)
- Have fuel-burning appliances inspected yearly by a qualified technician
- If a CO alarm sounds, get everyone outside immediately and call 9-1-1.
Ontario’s updated carbon monoxide alarm requirements taking effect on January 1, 2026 are designed to provide earlier detection and stronger protection against an invisible but very real risk. Homeowners, condo owners, landlords, and tenants all have a role to play, by understanding where alarms are required, ensuring they are properly installed and maintained, and responding quickly if an alarm signals danger. These changes are a practical reminder that small safety measures can make a life-saving difference.