How to change a smoke alarm battery
The low-battery chirp, the battery swap, and the monthly test.
How to change a smoke alarm battery
- 1Twist the alarm off its base, anticlockwise.
- 2Open the battery door.
- 3Take out the old battery.
- 4Put in a new one of the type printed inside, + to + and − to −.
- 5Close the door and twist the alarm back on.
- 6Press and hold the test button until it sounds.
Many fire services suggest a new battery once a year, at a date you'll remember, even before it chirps. Check the date on the back too: alarms wear out, and are replaced 10 years after they were made. Wired-in alarms have a backup battery that is changed the same way.
Safety
- Use a sturdy step ladder with someone holding it, not a chair.
- Don't leave an alarm without a battery to stop false alarms.
- If the alarm is wired into the house, switch off its circuit at the breaker before unplugging it, or ask an electrician.
- Replace any alarm 10 years after the date on its back, and test alarms every month.
General information, not professional advice: your manual and local rules come first. You use this at your own risk; see our Terms.
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