How often should carbon monoxide alarms and connected appliances be replaced?

• A. When they reach the end-of-life signal or the manufacturer's replacement date
• B. Every year
• C. Every 5 years
• D. When the device fails a self-test

Answer: (A)

Carbon monoxide alarms have a finite lifespan because the sensors and electronics gradually degrade, reducing their ability to detect CO accurately. To keep safety levels reliable, manufacturers specify an end-of-life date or provide an end-of-life indicator, and you should replace the unit when that signal occurs or when the manufacturer recommends replacement. Relying on a self-test to determine when to replace isn’t as trustworthy because a unit can pass a self-test yet still have degraded sensing performance long before or after that test. Replacing on the end-of-life signal or the manufacturer’s replacement date ensures the device continues to provide timely and trustworthy CO detection.