Do you *really* have to replace carbon monoxide detectors on the date they say in the outside, or does the battery just need changing? π€¨
@dajbelshaw Depends on the sensor being used.
It looks like all the major types of CO sensors are pretty durable.
I think the convention of replacing your detector came from smoke detectors, which use a radioactive source, and thus will indeed run out in a way that can't be recharged. Companies were more than happy to capitalize on this consumer habit with similar systems.
That said, it really is hard to tell how a specific sensor is engineered. Physical systems do eventually break down.
Ionising smoke detectors use americum, which has half-life of ~400 years - in any case it seems like they were gradually replaced by optical detectors - basically LED and sensors in a dark chamber
@kravietz @dajbelshaw A half life of 400 years doesn't necessarily mean they last 400 years.
The engineers are likely using as little Americium as possible, because it's radioactive and expensive, so it's hard to tell exactly when it'll get below the useful threshold. You just can't know without the engineering specs used (or reverse engineering, which is really dangerous when Americium is involved). All you can be confident in is that they hit their target lifespan.