Once you receive a low-battery alert on your smartphone, you can purchase a Roost Battery Replacement.
Once you receive the battery replacement, remove the Roost Smart Battery from your smoke alarm. Then disconnect the smart module from the bottom of your old battery and attach it to the new Battery Replacement. Reinstall the new battery (with the smart module attached) in your smoke alarm. Please test your new Smart Battery by pressing "test" on your smoke alarm. You should hear your smoke alarm sound and receive a notification in your Roost app. If you do not receive a notification, please contact Roost Support.