Stop a smoke alarm from chirping
A single chirp every 30 to 60 seconds is the alarm asking for a new battery. If it keeps chirping after a fresh one, it may need to be reset, or it may have reached the end of its life. Smoke alarms are meant to be replaced after 10 years, and the date is printed on the back. There's a reason the chirp tends to start in the middle of the night: a weak battery struggles most as the house cools off.
Why alarms chirp
Alarms chirp for a low battery, and they're designed to be annoying on purpose so you don't ignore it. It tends to happen at night because batteries lose a little voltage as the house cools down, which pushes a weak battery below the threshold.
Smoke alarms also expire. The sensors lose sensitivity, and most manufacturers say to replace the whole unit every 10 years. Many chirp at end of life, and no new battery will stop it.
Reasons it won't stop
The most likely reason, and the cheapest to rule out.
Batteries lose a bit of voltage as the house cools, which is why weak batteries chirp at night.
Most alarms are meant to be replaced every 10 years. Many chirp at end of life, and no battery will stop it.
Some alarms keep chirping after a battery change until you hold the test button to clear the memory.
| What you hear | What it usually means | What to do |
|---|---|---|
| One short chirp every 30 to 60 seconds | Low battery | Replace the battery, then hold the test button to reset. |
| Still chirping after a new battery | Memory not cleared, battery not seated, or end of life | Hold test for 15 to 20 seconds. Check the date on the back. |
| Three loud beeps, a pause, repeating | Smoke alarm | Get everyone out. Call 911 from outside. |
| Four loud beeps, a pause, repeating | Carbon monoxide alarm (on CO or combo units) | Get everyone out into fresh air. Call 911 from outside. |
| Several chirps together, or a voice saying end of life | End of life on many models | Replace the alarm. Check the label for your model's signals. |
| Every alarm in the house sounding together | Hardwired alarms are linked | Find the one with the fast-flashing light. That one started it. |
Silence the chirp
- Find the chirperStand still and wait for the chirp. Sound bounces, so check each alarm's light. The chirping one often has a flashing or different-colored light.
- Twist it off and check the dateMost alarms twist counter-clockwise off the base. On a hardwired alarm, unplug the wiring connector from the back, or turn off its breaker first if you're unsure. Look for the manufacture date on the back.
- Replace the batterySwap in a fresh battery, pressing it firmly into place. For hardwired alarms, there's still a backup battery inside. If the label says it has a sealed 10-year battery, there's nothing to replace; a chirp means the whole alarm is due for replacement.
- Hold the test buttonHold it for 15 to 20 seconds. This clears the memory on many models, and some keep chirping without it. Some manufacturers have you do this with the battery out, so check the instructions on the back of the alarm.
- Reinstall and testTwist it back on and press test. You should hear a loud alarm.
Watch it done
- The chirping has stopped
- Pressing test gives a loud alarm
- The battery drawer is fully closed and the alarm is twisted onto its base
If a new battery didn't stop it
Hold the test button for 15 to 20 seconds to clear the alarm's memory, and make sure the battery drawer is fully closed. Some won't make contact otherwise.
A hardwired alarm has a backup battery too. Replace it, then hold the test button to reset it.
If an alarm goes off every time you cook, it may be too close to the kitchen. NFPA guidance suggests keeping smoke alarms about 10 feet from cooking appliances where possible; the alarm's instructions list its own placement rules. Photoelectric alarms tend to have fewer false alarms from cooking.
What a pro typically charges (a rough estimate; prices vary by area): New smoke alarms cost $15–$60 each. An electrician typically charges $100–$250 to replace hardwired alarms.
Find an electrician near you