On the covered First Alert smoke and carbon monoxide alarm, chirping on an older alarm means an expired alarm. First Alert says smoke alarms lose reliability after 10 years, and that a chirp on an older unit can be an end-of-life warning. First, remove the unit from its mounting bracket and read the manufacture date on the back label.
Differential
Likely causes of “First Alert smoke and carbon monoxide alarm chirping on an older alarm”, and how to tell them apart
- 1
The alarm has reached the end of its life
What separates it The unit is ten years old or more, and it chirps at intervals even with a good battery
How to confirm Take the alarm off its bracket and read the manufacture date on the back label
- 2
What separates it The label is worn, painted over or missing
How to confirm Treat the alarm as expired and replace it
- 3
A chirp about once a minute from an old alarm
What separates it The alarm chirps with a battery that is known to be good
How to confirm Replace the alarm if it is near or past the ten-year mark
- 4
A sealed battery that has run down
What separates it The chirp comes about every thirty seconds on a sealed-battery model
How to confirm Replace the whole unit, as the battery cannot be changed
- 5
Dust or insects in the sensing chamber
What separates it The alarm gives false alarms or odd chirps in a room that is dusty or damp
How to confirm Vacuum the vents gently, but replace the alarm if it is old
Before you touch a setting
Record this first — changing settings destroys the evidence
- The manufacture date printed on the back label
- The model number, which tells you whether the battery can be changed
- The chirp pattern and how often it repeats
- How long the alarm has been up and whether it has ever been cleaned
Try in this order
0 of 8 completedWhat to do first
ReversibleRemove the unit from its mounting bracket and read the manufacture date on the back label.
Correct only the documented fault domain
ReversibleFirst Alert says to replace the entire unit if it is near or past the 10-year mark, and to replace it immediately if the label is missing or unreadable.
Take the alarm off its bracket
ReversibleTwist it gently counter-clockwise to release it from its base. On a hardwired model, switch off the circuit first and unplug the connector.
Read the back label
ReversibleLook for a manufacture date or a replace-by date. A label that has faded may still show a few digits that tell you the year.
Count the years
ReversibleTen years from the date of manufacture is the limit. A chirp from an alarm at or beyond that age is an end-of-life warning.
Replace the alarm if it is old
ReversibleBuy a new alarm of the same type, with a sealed or changeable battery as you prefer, and fit it to the bracket.
Test the new alarm
ReversiblePress the test button on the new alarm and check that it sounds, and test the others in the home at the same time.
Dispose of the old alarm properly
ReversibleFollow local rules, since some alarms contain a small radioactive source or a battery that should not go in household waste.
Model-specific
What is true of this model and not of its siblings
- The condition on this page
- An expired alarm, past its ten-year life.
- Parts involved
- The whole alarm, since the sensor cannot be replaced separately.
- Source
- First Alert's guide to chirping and beep patterns.
Stop boundary
When this stops being a self-service repair
- !Replace the entire unit if it is near or past ten years old, as First Alert says
- !Never remove an old alarm without a working one to replace it, since a home with no working alarm is at risk
- !Contact First Alert if you are unsure of the date or the model
Evidence ledger
Sources behind this answer
Exact questions
Common questions
What does chirping on an older alarm mean on a First Alert smoke and carbon monoxide alarm?+
An expired alarm. First Alert says smoke alarms lose reliability after 10 years, and that a chirp on an older unit can be an end-of-life warning.
How long does a First Alert smoke alarm last?+
About ten years from the date of manufacture, after which the sensor can lose its reliability.
Can I fit a new battery instead of replacing it?+
Only on a model with a changeable battery, and not once the alarm is near or past ten years old.
Where is the manufacture date printed?+
On the back or the side label, which you see once you remove the alarm from its bracket.
What if the label is missing or unreadable?+
First Alert says to replace the alarm immediately, because its age cannot be known.
Does every chirp mean replace the alarm?+
Not every chirp, since a low battery chirps too, but on an old alarm a chirp is often an end-of-life warning.