The alarm provides continuous protection from smoke and fire, even during power outages.
At the end of alarm life, the unit will chirp, indicating the alarm is in need of replacement. Industry experts (such as the NFPA), recommend that both ionization and photoelectric smoke alarms be installed to help insure maximum detection of the various types of fires that can occur within the home. Kidde Worry-Free Living Area Smoke Alarm with Sealed Lithium Battery Power, Model P3010L | CVS Ionization sensing alarms may detect invisible fire particles (associated with flaming fires) sooner than photoelectric alarms.