Smoke Detectors and Carbon Monoxide Detectors Recalled
That annoying "chirp" sound your smoke detector makes when the battery is low is actually a good thing. It's alerting you to change the battery before a real threat is present and it's useless.
Unfortunately, WCVB reports that millions of smoke and carbon monoxide detectors are being recalled because they stop "chirping" after seven years. You may think it's still working and the battery is fine, but it's not.
"The recall involves the Kidde NightHawk talking combo smoke/carbon monoxide alarm with model number KN-COSM-IB. The alarms are hard-wired into a home's electrical system." Eight malfunctions have been reported, without injury.