A short chirp every minute or so almost always means the battery is low. In a hardwired alarm, it is usually the backup battery. If a fresh battery does not stop it, the alarm may be at the end of its life. The USFA says to replace smoke alarms every 10 years. Never leave one out without replacing it.
The usual causes
A low battery. This is the most common cause.
A low backup battery in a hardwired alarm. Hardwired alarms have a battery for power outages, and it wears out too.
An alarm at the end of its life. Many alarms chirp when they reach it, even with a good battery.
A battery that is not seated fully, or a battery door left open.
Finding the one that is chirping
A chirp is hard to place, especially with alarms in several rooms. Stand under each alarm and wait for the next chirp. Many alarms have a small light that blinks differently when the battery is low. Write down which one it was so you are not hunting for it again. If your alarms are linked, they may all sound in an alarm, but a low-battery chirp usually comes only from the one that needs attention.
Safe steps
Use a sturdy step stool, not a chair, and have someone hold it if you can.
Replace the battery with the type printed on the alarm or in its manual.
Press the test button to make sure it sounds.
Check the date on the back. If it is 10 years old or older, or you cannot find a date, replace the alarm.
If you are not steady on a ladder, ask a family member or call us.
Hardwired alarms
A hardwired alarm is connected to your home’s wiring. You can change its backup battery yourself, the same way as a battery alarm. Replacing the alarm itself means working with the wiring, so leave that to an electrician. Never pull one down and leave it disconnected to stop the noise, even for one night. A missing alarm gives no warning at all.
Talk to a real person
Call (602) 999-2770 and a person answers, any hour. We install and replace hardwired smoke alarms, and we can check that linked alarms all sound together. You will hear the price before anyone drives out.
A full alarm, not a chirp, means treat it as real. Get everyone out and call 911 from outside.
Common questions
Why does my smoke detector chirp at night?
Batteries lose voltage as the house cools overnight, so a weak battery often starts chirping in the early morning hours.
I changed the battery and it still chirps. Why?
The battery may not be seated, the alarm may need a reset per its manual, or the alarm may be at the end of its life.
