If that old smoke detector, stained with paint or discolored with years of household grime, could send you a silent message, 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 detectors every 10 years,” says Nicolette Nye, a public affairs specialist with the Consumer Product Safety Commission (CPSC). Both organizations cite sensor degradation rates of 3 percent per year for their replacement recommendations.

“After 10 years, there’s a 30 percent potential failure rate,” says Nye, who also cited a CPSC recommendation that consumers look for smoke alarms 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, according to 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 it’s time the unit was replaced,” says Mahoney.

The NFPA not only recommends 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 you’re going to miss it, especially if you have battery-only systems,” Mahoney says.

According to the CPSC, smoke alarms and carbon monoxide detectors represent good investments in your family’s safety. Nye says, “Consumers who have working smoke alarms in their homes die in fires at about half the rate of those who do not have them. 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 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 near cooking appliances, manufacturers have improved the technology. NFPA’s Mahoney says, “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 available to enhance the safety of the hearing impaired, says CPSC’s Nye, adding that those include bed shakers and strobe lights offering another level of alert to fire or carbon monoxide danger.

Carbon monoxide detectors are designed to sound the alert before carbon monoxide reaches life threatening levels. Photo Source: Abi Begum