The kidde 10y29 alarm features an innovative early and silent low battery warning this means that rather than chirping and beeping an led light will flash at the early signs of the battery running out after 30 days the alarm will then start chirping for 30 more days to indicate the end of life this silent alert feature will be a real benefit when low ambient temperatures occur as this decreases the batterys temperature and therefore voltage this typically occurs during the early hours of