Where to Put a Carbon Monoxide Detector?

Proper placement is critical for a carbon monoxide (CO) detector to work effectively. CO is roughly the same density as air and mixes evenly throughout a room, but placement can still be affected by airflow and potential sources.

The Most Important Rule: Follow Manufacturer's Instructions

Always check the manual that comes with your specific detector first, as it may have model-specific requirements.

Ideal Placement: The "Where"

1. On Every Level: Install at least one CO detector on every level of your home, including the basement.

2. Near Sleeping Areas: Place a detector within 10 feet of every bedroom door. The goal is to be loud enough to wake everyone up if it alarms during the night.

3. Mount High or Low? Mount it on the wall at chest height or on the ceiling.

• Why? While CO mixes with air, this placement avoids dead air spaces and makes testing and battery replacement easier. Many manufacturers recommend placing it at least 5 feet from the ground to avoid pet interference or accidental bumps.

• Note: Some detectors are specifically designed for plug-in outlets near the floor. Always follow the manufacturer's guidelines.

Critical Placement: The "Where Not To"

Avoid these locations, as they can lead to false alarms or prevent the detector from sensing CO accurately:

• ❌ Within 5 feet of Fuel-Burning Appliances: Do not place it directly next to your furnace, water heater, fireplace, or stove. The initial burst of CO during startup could trigger a false alarm before the appliance vents properly.

• ❌ In or Near Humid Areas: Avoid bathrooms, saunas, or very damp rooms. Excessive moisture can damage the sensor.

• ❌ Near Windows, Doors, or Vents: Drafts from these openings can disperse CO, preventing it from reaching the detector in sufficient concentration.

• ❌ In Direct Sunlight or Extremely Hot/Cold Areas: Don't place it in an attic or unfinished garage where temperatures exceed the detector's operational limits (check the manual).

• ❌ In Areas with Obstructions: Avoid placing it behind furniture, curtains, or in any corner where air circulation is blocked.

Summary of Best Practices

• DO: Place on every level and outside all sleeping areas.

• DO: Mount on a wall or ceiling according to the manufacturer's height recommendation.

• DO: Interconnect detectors if possible, so when one sounds, they all sound.

• DON'T: Place too close to appliances or in dead air spaces.

• DON'T: Forget to test your detectors monthly and replace them every 5-7 years (check the expiry date on the unit).