The law is changing for carbon monoxide alarms

Which homes need one, where to install them and more

Feature story

As of January 1, 2026, changes to the Ontario Fire Code will require increased carbon monoxide (CO) alarm detection in residential occupancies and care occupancies.

CO is a silent killer: it’s colourless, odourless, tasteless and can be deadly when inhaled in high concentrations. It’s produced when fuels like wood, gas, oil, or propane don’t burn completely. Without proper ventilation, CO can build up indoors, making a working carbon monoxide alarm essential for home safety.

A carbon monoxide alarm is a device that detects unsafe levels of CO in your home and sounds an alarm to warn you to evacuate. Because CO is undetectable by human senses, an alarm is the only reliable way to know that it is present.

 

In Ontario, carbon monoxide alarms are legally required in any home that has:

• A fuel-burning appliance (like a gas stove, water heater, or fireplace),
• A wood-burning fireplace, or
• An attached garage

This applies to detached houses, townhouses, apartments and condos.

 

Where should CO alarms be installed?

In houses and townhomes where CO alarms are required:

• CO alarms are required adjacent to each sleeping area and as of January 1, 2026, on every level of the home.
• For example, if bedrooms are on the same floor but far apart (for example, on opposite sides of a living room) you need two CO alarms on that floor: one in the hallway outside each group of bedrooms.

If a building has a storage garage, you must install CO alarms:

• Next to each sleeping area in any apartment or care unit that shares a wall, floor, or ceiling with the garage
• On every level of those same units that doesn’t have a sleeping area
• Next to each sleeping room that isn’t part of a dwelling unit (for example, a staff sleep room)

If a building is heated by a forced-air fuel-burning appliance that’s not inside a home or care unit, you must install CO alarms:

• In the service room or area where the appliance is located (if it’s in the building)
• In any public hallway heated by the appliance:
  • At least one alarm in each section if the hallway is divided
  • Alarms spaced no more than 25 metres apart in undivided hallways
• Next to each sleeping area in any unit heated by the appliance
• On every level of those units that doesn’t have a sleeping area

 

Testing and maintaining your CO alarm

Carbon monoxide alarms need regular testing and replacement to work properly:

• Test monthly by pressing the “Test” button
• Replace batteries yearly (unless your alarm uses a sealed battery)
• Replace the alarm every seven to 10 years, or according to manufacturer instructions. Look for models marked CSA-6.19 or UL 2034 to meet safety standards.

Renters should test alarms monthly and report any issues to their landlord. Landlords are responsible for ensuring working alarms are installed.

 

CO safety tips for winter

As temperatures drop and we close our windows, CO risks increase. Follow these tips to stay safe:

• Book an annual inspection of all fuel-burning appliances: furnaces, fireplaces, gas stoves, gas dryers and chimneys.
• Keep vents, intakes and exhaust pipes clear of snow and debris.
• Never idle your car in the garage, even with the door open.
• Only use generators and fuel-powered equipment outside, far from windows, doors, or vents.
• Do not use gas stoves, ovens, BBQs, or camping equipment to heat your home unless the device is designed for indoor use.

 

For more fire safety tips and resources, visit Ottawa Fire Services’ Fire safety, prevention and education page or contact the Fire Prevention and Education Team.