How often should I test smoke alarms?
Test monthly using the test button, replace batteries as recommended for your device, and replace whole units at the end of the service life printed on the housing.
Last reviewed 2026-07-15
Sensors degrade with age regardless of battery condition, which is why alarms carry an expiry date. An alarm that beeps on test can still be past its useful sensing life.
Placement matters as much as testing: inside each sleeping room, outside each sleeping area, and on every level of the home.
What to check first
- Manufacture or expiry date printed on the alarm housing
- Coverage on every level and outside every sleeping area
- Carbon monoxide alarms present where fuel-burning appliances or an attached garage exist
- Interconnection, if the home has interconnected alarms
When to call a professional
- Hardwired alarms fail after replacement or chirp continuously with new batteries
- A CO alarm activates — leave the building first and call emergency services