Carbon monoxide detectors typically have a replacement interval equal to:

• A. Seven years
• B. Five years
• C. Ten years
• D. Fourteen years

Answer: (A)

CO detectors have a limited lifespan because the sensors degrade over time, and their accuracy can drop. To ensure reliable protection, these devices are treated as having a finite service life. The standard replacement interval you’ll see in safety guidance and manufacturer recommendations is about seven years. This reflects the point at which the detector’s ability to sense carbon monoxide with guaranteed reliability is no longer assured. While some models may be rated for five years or others for longer than seven, seven years is the typical interval used in training and practice, making it the best choice. Replacing earlier—though possible—risks unnecessary costs, and delaying beyond seven years increases the chance of failure to alert.