The answer to 'carbon monoxide detector making buzzing noise' is that a buzzing or chirping sound from a carbon monoxide (CO) detector is often an indication of a problem. This could be due to a low battery, a sensor issue, or the detector reaching the end of its lifespan.
If the detector is making a consistent buzzing or beeping sound, it's important to address the issue promptly. Start by replacing the batteries. If the sound persists, the detector may need to be replaced, as the sensor could be malfunctioning. In some cases, the detector may be nearing the end of its 5-7 year lifespan and will need to be replaced entirely.