How long the battery of a smoke detector lasts depends greatly on a number of factors:
- The type of battery
- Whether the detector is wirelessly linked or not
- How often the detector is tested and/or goes into alarm
- Operating temperature
In general you can expect the following life expectancy:
- Detectors with 9V batteries (supplemented with AA batteries for wirelessly connectable devices): replace annually.
- Detectors with AA batteries: +- 3 years if not paired, +- 1 year if paired
- Detectors with built-in lithium battery: device life (maximum 10 years)