Install Carbon Monoxide Alarms for Complete Home Coverage

Proper carbon monoxide (CO) alarm placement and installation helps your home get the earliest warning possible. This guide covers where to install CO alarms, how many you may need, installation basics for different power types, rental/apartment considerations, and what to do if your alarm goes off.

Where to Install Carbon Monoxide Detectors
Mounting Height: You Don’t Need to Install Near the Floor
Hardwired vs Battery vs Plug-In: Installation Guides
Tools Required & Safety Tips
How Many CO Detectors Do I Need?
Placement by Home Layout (Ranch, 2-Story, Basement, etc.)
CO Detector Placement in Apartments & Rental Properties
What to Do If Your CO Alarm Goes Off
FAQs

Where to Install CO Detectors

Carbon monoxide (CO) is an invisible, odorless killer. For maximum safety, install CO alarms in these key areas:

Outside every sleeping area: Hallways near bedroom doors.
On every level: Including finished and unfinished basements.
Common living spaces: Areas where your family spends the most time.

Common locations to avoid

Garages: Exhaust fumes cause frequent false alarms.
Next to appliances: Spacing avoids triggers from normal fuel-burning operation.
Humid areas: Keep away from steamy bathrooms or laundry rooms.
Obstructions: Avoid tight corners, curtains, or direct airflow from vents and fans.

Installation & Mounting Height

Contrary to the myth that CO "sinks," it mixes with air throughout the room. Follow manufacturer instructions for wall or ceiling mounting at a height that is easy to access for monthly testing.

Power Options

Battery-Operated: Fastest for older homes and rentals. Mark, drill, mount, and test.
Plug-In: Best for hallways. Use an outlet not controlled by a wall switch.
Hardwired: Best for new construction. These interconnect for whole-home alerts; professional installation is recommended.

How Many Do I Need?

At a minimum, install one alarm per floor and one near every bedroom.

Add more if: Your home has separate wings, a finished basement, or long hallways.
For Rentals: Focus on bedroom hallways and use battery units if drilling is restricted. Check your lease for specific mounting rules.

Maintenance & Safety Checklist

Monthly Tests: Establish a routine to check sensor functionality.
Cleaning: Lightly vacuum or brush sensors to remove dust buildup.
Never Paint: Avoid painting over the unit or covering its vents.
Expiration: Replace units immediately when the end-of-life signal sounds.

Emergency Response: If the Alarm Sounds

Exit Immediately: Move everyone to fresh air or an open window.
Call 911: Contact emergency services once you are outside.
Stay Out: Do not re-enter until cleared by emergency professionals.
Medical Check: Seek help for headaches, dizziness, or nausea.
Professional Inspection: Have a technician check all fuel-burning appliances before returning.