Smoke and CO alarms · triage
Smoke or CO alarm chirping, even with a new battery
The short answer
A full, continuous alarm means act now. A single chirp about once a minute is a low battery or the alarm reaching end of life. Check the date on the back: NFPA recommends replacing smoke alarms 10 years after the manufacture date.
Continuous alarm = actIf the alarm sounds continuously: for smoke, get out and call 911; for CO, get to fresh air and call 911.
Every outcome on this card
Emergency nowThe alarm is sounding
Smoke: get out. CO: fresh air. Call 911.
- Get everyone out
- Call 911 from outside
- Stay out until responders clear the house
This weekThe alarm has reached end of life
Replace it this week.
- Replace the whole alarm, not just the battery Many alarms chirp at end of life by design.
- Write the install date on the new one And add it to your record.
- Test it with the button NFPA: test alarms monthly.
Sensors degrade. NFPA recommends replacing smoke alarms 10 years from the manufacture date; CO alarm life varies by model, so follow the label.
This weekA battery or a reset
This week; sooner if it is your only alarm.
- Use a fresh, correct battery and seat it fully Some chirp until the battery drawer is fully closed.
- Hold the test button 15–20 seconds to clear the memory
- Hardwired alarms have a backup battery too If it still chirps, replace the alarm.
Related
Written from
Original casaq guidance, updated 2026-10-05. General guidance, not a diagnosis; licensed-pro review pending. Severity levels: Emergency now / Today / This week / This month / Watch. Send a correction.
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