The answer to 'carbon monoxide detector buzzing noise' is that a buzzing or beeping sound from a carbon monoxide (CO) detector is usually an indication of a problem. Common causes include low battery, sensor malfunction, or the detector reaching the end of its lifespan.
If the detector is beeping intermittently, it likely means the battery is low and needs to be replaced. If the beeping is constant, it could mean the sensor is malfunctioning and the entire unit needs to be replaced. CO detectors typically last 5-7 years, so a persistent buzzing may also signal that the device has reached the end of its useful life and should be upgraded.