Carbon Monoxide Detector Replacement FAQs

Carbon monoxide detectors, commonly shortened to CO alarms, need to be replaced regularly in order for them to continue operating correctly. Whether you have a non-digital, digital, or combo alarm, there are signs to watch out for in order to keep yourself protected.

Learn How Often to Replace CO Detectors

Carbon monoxide detector replacement is crucial to keeping you and your loved ones safe, especially if your CO alarm is starting to near the end of its life span.


Is your carbon monoxide alarm beeping? To determine if your alarm is at the end of its life, refer to the following:

  • End-of-Life warning will sound every 30 seconds

  • If the alarm has a digital display, it displays the ERR or END error code

  • The beep will ONLY STOP when the alarm is out of power

  • Replacing the battery WON'T STOP the beep

Carbon monoxide alarms do not detect the presence of carbon monoxide when in end-of-life mode, which is why it's important to take precautionary steps when you realize your CO detector is nearing time to be replaced.


Do you have a non-digital carbon monoxide alarm? To determine if your carbon monoxide non-digital alarm has reached its end of life, refer to the following:

  • When the CO alarm emits a quick beep every 30 seconds and the red LED flashes, you may need to change the batteries.

  • Replace the batteries in the alarm

  • If the alarm continues to emit a quick beep every 30 seconds and the red LED flashes, the alarm has reached the end-of-life.

To determine if your combo alarm has reached its end-of-life, look for these signs:

  • If the alarm emits a chirp every 30 seconds, it is either an end-of-life alert or a sensor error

  • If the alarm emits a chirp every 60 seconds, it indicates the battery power is not sufficient to power the unit in full alarm

  • An end-of-life or sensor error will not respond to a battery change

How Long is a Kidde Carbon Monoxide Detector Good For?

In 2009, Underwriters Laboratories (UL), began requiring an end-of-life warning to alert homeowners when their carbon monoxide alarm has reached the end of its useful life. As an industry leader committed to safety, Kidde has included this feature in all its carbon monoxide alarms since 2001. Kidde carbon monoxide alarms have a proven life of seven to ten years, depending on the model type.


As of 2013, ALL Kidde carbon monoxide alarms have a 10-year life, with the following exceptions: Model KN-COEG-3, KN-COPE-I and KN-COPP-3. If your CO alarm was manufactured before 2013, it has a seven-year life.


If you're unsure of your alarm's age, look for the manufactured date on the back of the alarm.


In accordance with the National Fire Protection Association (NFPA), Kidde recommends replacing smoke and heat alarms every ten years and replacing carbon monoxide and combination alarms every seven to ten years (depending on your model) to benefit from the latest technology upgrades. Carbon monoxide detector replacement is a quick way to ensure that the presence of CO is detected accurately.


For more assistance, please email or call Kidde Consumer Product Support at 1-800-880-6788 Monday through Friday from 8:00 AM – 5:00 PM EST Saturday 9:00 AM – 3:00 PM EST.




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