How to reset a smoke alarm

Some smoke alarms are hard-wired into the electrical system of a house, while others utilise batteries to power the device. Smoke detectors only draw a small amount of a house's power but batteries have finite reserves and need to be replaced periodically, followed by an alarm reset. Continuous beeping or flashing lights indicate that the alarm has faulted or the unit's batteries need to be replaced.

Locate the reset button on the alarm and press it. Press and hold the "Test" button on the alarm for 10 seconds if the smoke alarm does not have a dedicated reset button.

Remove the battery cover if the beeping or flashing continues. Depending on your model, you may need to remove the alarm from the wall or ceiling to replace the batteries.

Remove the old batteries from the smoke alarm.

Press and hold the "Test" button for 15 seconds. Remove your finger when the alarm begins to "chirp." Place new batteries in the unit once the chirping stops.

Replace the battery cover or return the alarm to its position on the wall.

Press the reset button or hold the "Test" button to reset the smoke alarm.


If the smoke detector is connected to the house electrical system in any way, disconnect the power to the smoke alarm prior to replacing the battery. Do not remove the batteries to silence an alarm caused by cooking smoke or heat. Different models of smoke alarms use different types of batteries.

Things You'll Need

  • Batteries
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About the Author

Brad Chacos started writing professionally in 2005, specializing in electronics and technology. His work has appeared in, Gizmodo, "PC Gamer," "Maximum PC,",, "Wired,", and more. Chacos is a frequent contributor to "PCWorld," "Laptop Magazine" and the Intuit Small Business Blog.