Where Should Carbon Monoxide Alarms Go? A Room-by-Room Home Check

Carbon monoxide is invisible and odorless. EPA guidance gives homeowners a practical starting point for where alarms belong and how often to test them.

Last updated: October 8, 2026.

Carbon monoxide can build up without a smell or visible warning. Alarms are one of the simplest layers of protection, but placement matters.

Quick takeaway: EPA recommends CO alarms in a central location on every level of livable space, near or inside each sleeping area, and inside the home near a door to an attached garage. Follow the alarm manufacturer’s instructions and local codes.

Every Livable Level

Include the basement when it is part of the home’s livable space. A single alarm on one floor may not provide the same warning throughout a multi-level house.

Near Sleeping Areas

Place alarms where they can wake people. EPA recommends placement near or inside each sleeping area.

Attached Garages Need Attention

Vehicles and fuel-burning equipment can create carbon monoxide. EPA recommends an alarm inside the home near the door leading to an attached garage and in rooms located over the garage.

Keep Distance From Fuel-Burning Appliances

EPA’s infographic calls for alarms to be at least 15 feet away from fuel-burning appliances, while still following the device manufacturer’s instructions and applicable codes.

Test Monthly

Testing confirms the alarm electronics and sounder are responding. Replacement schedules vary, so check the date and manufacturer instructions rather than assuming the unit lasts forever.

The Bottom Line

A CO alarm is inexpensive compared with the risk it helps address. Make placement, testing and replacement part of routine home maintenance.

Source: U.S. EPA — Carbon Monoxide Alarms.

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