Carbon monoxide detector: choosing and placing one

What a carbon monoxide alarm detects

Carbon monoxide (CO) is a toxic gas produced by incomplete combustion. It cannot be seen or smelled. A CO alarm is different from a smoke alarm and from a carbon dioxide (CO₂) monitor; choose a device specifically certified to detect carbon monoxide.

• It is especially important near fuel-burning equipment or an attached garage.
• Never run grills, camp stoves or generators inside homes, garages or enclosed spaces.
• A combination alarm should clearly identify every hazard it detects.

Where to place it

Placement and height depend on the model, building layout and local rules. Follow the manufacturer's manual. Protect sleeping areas and rooms with fuel-burning appliances while avoiding steam, grease, strong drafts and obstructions that may interfere with the sensor.

• Do not hide the alarm inside a cabinet or behind curtains.
• Keep the specified distance from appliances, windows and vents.
• Multi-level homes may need more than one alarm.
• Do not follow a generic mounting height that conflicts with the manual.

Test, power and replace it

Use the test button at the interval stated by the manufacturer, clean the unit as directed and replace batteries or the entire alarm when due. Keep the manual so everyone can distinguish a low-battery signal from an end-of-life warning or a CO alarm.

What to do when it alarms

Do not ignore the alarm or search for the source. Move everyone, including pets, into fresh air and call emergency services from a safe location. Do not re-enter until responders or a qualified professional say it is safe.

• Headache, dizziness, weakness, nausea, chest pain and confusion can indicate poisoning.
• Sleeping people, infants, older adults and people with chronic illness may be especially vulnerable.
• Tell emergency services immediately if anyone is unresponsive or struggling to breathe.