Safety
When to Replace Hardwired Smoke Alarms
Updated
Short answer
Replace smoke alarms about 10 years after the manufacture date printed on the back. If a hardwired alarm keeps chirping after a new backup battery, it has likely reached end of life.
Check the date
Twist the alarm off its base and read the date on the back.
Interconnection
Interconnected alarms sound together, so a fire in the basement wakes people upstairs.
Carbon monoxide
Homes with gas appliances, fireplaces or attached garages need CO alarms near sleeping areas.
When to call an electrician
If anything is warm, smells hot, sparks or keeps failing after the simple checks above, stop and call. The electrician will test the circuit, find the cause and make it safe. Related service: Smoke & CO Detector Installation.
Questions
Can I replace a hardwired alarm with a battery one?
Hardwired locations should stay hardwired; an electrician can replace them with compatible units.
Local help with smoke & co detector installation
City guides with local permit offices, utilities and housing notes:
Editorial note: this guide is general information for US homes, not a substitute for an on-site assessment by a licensed electrician. Codes and permit rules vary by location.