Carbon Monoxide Detector Law Changes in Ontario: What Homeowners Need to Know
Carbon Monoxide Detector Law Changes in Ontario: What Homeowners Need to Know
Carbon monoxide (CO) is often called the “silent” hazard because you can’t see it, smell it, or taste it. And when it’s present, you usually don’t realize it until symptoms show up — which can be too late.
That’s why Ontario has updated its rules for carbon monoxide alarms. If you own a home (or a rental property), this is worth understanding now, because many homes that were “fine” under the old setup will need additional protection to remain compliant.
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1. What’s Changing (and When)
Ontario Fire Code requirements for carbon monoxide alarms are expanding. The key change is this:
If your home meets certain conditions, you’ll need a CO alarm on every storey of the home — not just near bedrooms.
The updated requirements take effect January 1, 2026.
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2. Which Homes Are Affected
You generally need carbon monoxide alarms if your home has any of the following:
A fuel-burning appliance (gas, propane, oil, or wood furnace, boiler, water heater, stove, dryer, etc.)
A fireplace
An attached garage
Heated air supplied by a fuel-burning appliance located outside the home
If your home is fully electric with no attached garage and no fuel-burning sources, CO alarms may not be required under the Fire Code.
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3. Where CO Alarms Must Be Installed (Simple Version)
If your home meets the conditions above, CO alarms must be installed:
Adjacent to each sleeping area, and
On every storey of the home, including floors that don’t have bedrooms
This “every storey” requirement is the part that will catch many homeowners off guard, because older guidance often focused mainly on bedroom areas.
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4. What About Smoke / CO Combination Alarms?
Many homeowners don’t realize that combination smoke and carbon monoxide alarms are available — and they’re often a practical option.
Smoke/CO combo units:
Detect both smoke and carbon monoxide in a single device
Can simplify placement where both alarms are required
Reduce the total number of devices on walls and ceilings
Are commonly used near bedrooms and on main living levels
The key is that the device must be approved for both functions and installed according to the manufacturer’s instructions and the Fire Code. Not every location that needs a smoke alarm automatically qualifies for a combo unit — placement still matters.
For some homes, a mix of standalone CO alarms and combination units makes the most sense.
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5. Hardwired vs Plug-In vs Battery: What’s Allowed?
Carbon monoxide alarms may be:
Hardwired
Plug-in
Battery-operated
What matters most is that the alarm is approved, installed in the correct location, and maintained properly.
One thing homeowners often overlook: some plug-in and hardwired alarms do not function during a power outage unless they have battery backup. That’s worth checking before choosing a model.
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6. CO Alarms Need Maintenance Too (Not Just Installation)
Installing a CO alarm is only part of the equation.
Just like smoke detectors, carbon monoxide alarms:
Collect dust over time
Can become less responsive if vents are blocked
Have sensors that age and eventually expire
Basic maintenance includes:
Monthly testing using the test button
Periodic light cleaning or vacuuming to remove dust buildup
Replacing the entire alarm at the end of its service life (often 5–10 years)
This is similar to smoke detectors: a unit that’s never been cleaned or tested may still be mounted on the ceiling, but that doesn’t mean it will work when needed.
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7. The “It’s Never Gone Off, So It Must Be Fine” Assumption
A common misconception is that alarms are “working” simply because they haven’t activated.
In reality:
A failed sensor often stays silent
Dead or contaminated detectors don’t announce themselves
Some alarms only show trouble indicators that go unnoticed
Just like breakers that don’t trip when they should, a detector that never alarms isn’t always a good sign.
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8. What Homeowners Should Do Next
A simple, practical checklist:
Confirm whether your home has any fuel-burning sources, a fireplace, or an attached garage
Make sure CO alarms are installed near sleeping areas
Make sure CO alarms are installed on every storey
Check the age and condition of existing alarms
Confirm whether any combination smoke/CO units are properly rated and placed
If your home has a unique layout — older construction, mixed heating sources, or multi-unit considerations — it’s worth taking a closer look rather than assuming compliance.
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Final Thoughts
Ontario’s updated carbon monoxide alarm requirements are straightforward in principle:
If CO could be produced in or near your home, alarms should be installed near bedrooms and on every level.
Installation matters — but so does ongoing maintenance. A detector that’s clean, tested, and within its service life is far more likely to do its job than one that’s simply been hanging on the ceiling for years.
