Smoke & Carbon Monoxide Alarms

Working smoke alarms roughly cut the risk of dying in a home fire in half. Carbon monoxide (CO) alarms warn you of a gas you can’t see or smell.

Homeowners
Renters

Alarm locations in a two-story home: every bedroom, outside sleeping areas, every level. — Where to put smoke and carbon monoxide alarms in a two-story home

Smoke alarms

In every bedroom, outside each sleeping area, and on every level including the basement
On the ceiling or high on the wall, away from kitchens and bathrooms to reduce nuisance alarms
Interconnected alarms (when one sounds, they all sound) are best
Test monthly with the test button
Replace batteries as the manufacturer says (or use 10-year sealed battery alarms)
Replace the whole alarm every 10 years (check the date on the back)

Carbon monoxide alarms

Outside each sleeping area and on every level, if you have any fuel-burning appliance, a fireplace, or an attached garage
Test monthly; replace per the manufacturer (often 5 to 10 years)
Combination smoke/CO alarms are available

If the CO alarm sounds: get everyone outside to fresh air right away and call 911. Don’t go back in until responders say it’s safe. Symptoms of CO poisoning include headache, dizziness, nausea and confusion, and can feel like the flu.

Special needs

Alarms with strobe lights and bed shakers are available for people who are deaf or hard of hearing. Many fire departments install alarms for free.

Standards & references

Last updated: October 2, 2026