How to Replace the 9V Battery in a Smoke Alarm

Place your step-ladder beneath the smoke alarm so you can reach it on the ceiling or wall. Have someone support the ladder as you climb, if possible. Make sure you can easily reach the smoke alarm from your ladder; don't lean or stretch to reach because you can tip the ladder and injure yourself.

Remove the screws from the cover, if fitted. Some smoke alarms can be opened by pinching or twisting the smoke alarm's cover and pulling downward. In some cases, you might be able to unclip the alarm from the mounting on the ceiling or wall and work at ground level.

Pull the battery out of its plastic holder, and peel off the fastener that connects to the battery's positive and negative terminals. Discard the old battery and remove the replacement from its packaging. Always use fresh batteries in your smoke alarm.,

Connect the new battery to the unit. The octagonal terminal on the battery clips onto the circular connection on the plastic cover, and the circular connection on the battery clips into the octagonal terminal on the cover. The battery-connection cover should be held firmly in place when the battery is installed correctly.

Slide the new battery back into its plastic holder inside the smoke alarm and replace the cover, attaching the screws if necessary. Your new 9-volt battery should last approximately 12 months before needing replacing. You should change your smoke alarm battery every 12 months, even if the low battery warning doesn't sound.

Press the "Test" button on the smoke alarm when you have replaced the cover; the alarm should sound while you hold the button if the battery is working correctly. Use another battery or purchase and install a replacement alarm if the "Test" button fails to produce a sound.