DIChoose the maintenance pattern
Sealed vs Replaceable Smoke Alarm Batteries
The backup-battery design changes routine maintenance, but it does not change the need for monthly testing or end-of-life replacement.
Replaceable batteries
Traditional battery-powered and hardwired alarms may use replaceable batteries. Follow the model instructions, respond to low-battery chirps promptly and test after every battery change.
Sealed ten-year backup
A sealed backup is designed to remain with the alarm through its service life. It is not opened for yearly battery changes; when the sealed battery or alarm reaches end of life, the whole unit is replaced.
Hardwired is a separate question
“Hardwired” describes the primary power and interconnect arrangement. A hardwired alarm can have either a replaceable or sealed backup battery.
Detector Inspectors’ replacement models
The First Alert SM105-AC smoke alarm and SMICO105-AC smoke-and-CO alarm used in the published replacement services are hardwired models with sealed 10-year backups.
Safety references
Primary sources used for this page:
- First Alert SM105-AC product information
- First Alert SMICO105-AC product information
- North Metro Fire smoke and CO alarm program
Manufacturer instructions and current local requirements control. For an emergency, call 911.