If that old smoke detector, discolored, stained with paint or years of household grime, could send you a message silently, it might say “please replace me.” Those lifesaving warning devices designed to alert us to smoke and fire were never meant to last forever.
“The National Fire Protection Association and Underwriters Laboratories suggests replacing smoke every 10 years,” said Nicolette Nye, a public affairs specialist with the Consumer Product Safety Commission (CPSC). Both organizations cite sensor degradation rates of 3% per year for their replacement recommendations.
“After 10 years, there would a potential of a 30% failure rate,” said Nye, who also cited a CPSC recommendation that consumers look for smoke alarms rated of certified by Underwriters Laboratories designated by the symbol “UL” or the Electrical Testing Laboratories, marked with the “ETL” logo.
Both smoke alarms and carbon monoxide detectors are designed with a timeframe or useful lifespan of 10 years, said Shawn Mahoney, a National Fire Protection Association (NFPA) technical services engineer.
“Once they start to reach their end of life, consumers may notice alarm signals—typically a chirping sound that is either a low battery or an indication of the device’s end of life, meaning that it’s time the unit was replaced,” said Mahoney.

The NFPA not only recommends that batteries be replaced once a year, but also urges you to test the unit once a month as an added precaution against failure. Chirping, prompted by a drained battery will typically stop within seven days and when that happens, the unit stops functioning.
“If you’re just waiting to hear the sound and not testing regularly, there’s a possibility that you’re going to miss that, especially if you have battery-only systems,” Mahoney said.
According to the CPSC, smoke alarms and carbon monoxide detectors represent good investments in your family’s safety, said Nye, emphasizing that both types of devices should be replaced after 10 years. “Consumers who have working smoke alarms in their homes die in fires at about half the rate of those who do not have alarms. Install working carbon monoxide detectors on every level of the home and outside of sleeping areas. CO detectors are designed to sound the alert before carbon monoxide reaches life threatening levels.”
Design improvements are another great reason to consider replacement of older units. Ionization smoke alarms made their debut in the consumer market in 1970. Photoelectric smoke detectors were first patented in 1972, and the first 10-year lithium battery-powered smoke alarms hit the market in 1995. Since then, units using the best features of all three technologies have become popular.
Many states have upgraded building codes to require hardwired smoke alarms with battery backup power, and carbon monoxide detectors in all new residential construction.
As fire codes have evolved to require smoke alarms in close proximity to cooking appliances, manufacturers have improved the technology, said NFPA’s Mahoney. “They can distinguish between an actual fire event in the home and cooking fumes, reducing the incidence of nuisance alarms.”
Features for residential alarms and detectors are also available to enhance the safety of the hearing impaired, said CPSC’s Nye, adding that those include bed shakers and strobe lights offering another level of alert to fire or carbon monoxide danger.
Derrill Holly writes on consumer and cooperative affairs for the National Rural Electric Cooperative Association, the national trade association representing more than 900 local electric cooperatives. From growing suburbs to remote farming communities, electric co-ops serve as engines of economic development for 42 million Americans across 56 percent of the nation’s landscape.