Do I Need to Place Carbon Monoxide Detectors on Every Level of my House?

Yes, it is essential to have detection on every floor of your residence. According to the California Electrical Code (Title 24, Part 3), hardwired and interconnected carbon monoxide detectors with battery backup are required on every habitable level of a home.

Following this code ensures that if a carbon monoxide (CO) event is detected on one level—such as in a basement furnace room—every alarm throughout the structure will sound simultaneously. This interconnection provides the critical early warning needed to alert occupants, regardless of where they are in the house.

When planning your installation, keep these placement priorities in mind:

• Proximity to Sleeping Areas: The most crucial priority is placing a detector in the hallway immediately outside of bedroom doors to ensure the alarm is loud enough to wake occupants.
• The Breathing Zone: Detectors should be mounted 3 to 5 feet from the floor. Because carbon monoxide has a relative density nearly identical to air, it disperses evenly throughout a room. Mounting at this height allows the sensor to sample the air in the zone where you actually breathe.
• Distance from Appliances: To prevent nuisance alarms, maintain a safe distance from fuel-burning appliances like furnaces, water heaters, and gas stoves.
• Avoid Humid Areas: Do not install detectors inside bathrooms or laundry rooms, as high moisture and steam can damage the sensors or trigger false alerts.

• Carbon Monoxide Detector Placement Guide: Essential Home Safety Tips