The plug-in with display
First Alert CO615
Plugs into any outlet with battery backup and shows the actual ppm reading — the display turns a mystery chirp into information.
Gear guide · Air · updated October 2, 2026
Carbon monoxide alarms
If your home burns anything — gas, oil, propane, wood — or has an attached garage, Ontario law requires CO alarms adjacent to sleeping areas. They're $40–$80, they expire on a printed date, and they're the last line of defence behind the annual servicing and the audit's spillage check.
Not sure this category applies to your home? The 30-second screener flags it if so, and the carbon monoxide guide covers the testing side.
The other benchmark
Kidde Nighthawk (digital display)
The long-running Kidde equivalent — AC powered, battery backup, digital readout, and a peak-level memory button that tells you what happened while you were out.
The consolidator
First Alert combination smoke + CO
Where a smoke alarm is due for replacement anyway, a combination unit covers both requirements in one ceiling spot — check it carries both CSA marks.
Before you buy
- Look for CSA 6.19 certification — it's the Canadian standard CO alarms are tested to.
- Every CO alarm has an end-of-life date printed on the back, typically 7–10 years from manufacture. Check yours today; replace on schedule.
- One adjacent to each sleeping area is the legal minimum — one per storey with fuel appliances is the sensible spec.
- An alarm is the backstop, not the fix: annual appliance servicing and the audit's combustion spillage check come first.
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Measure, then act
Gear works best inside a plan: the planner reads your home's era, heating, and symptoms, flags the tests that matter, and puts the right categories on your list.
Also in gear guides: Radon monitors & test kits · Indoor air quality monitors · Air purifiers (HEPA)