CO2 and all other air quality indexers have to be very carefully calibrated regularly. It's not some slop you can just throw into a consoomer cheap iot device.

Article author completely ignores this for the obvious reasons.

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Gigachad 5 hours ago | parent | next [-]

For the purposes of indoor ventilation monitoring you can calibrate by occasionally exposing the sensor to fresh air. Either taking it outside or just the room not having people in it. The sensor will treat the lowest reading it gets as 400ppm since this is what outdoor air is.

A sensor mounted in the office will get calibrated every night when the office is empty.

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	▲	OutOfHere 3 hours ago \| parent \| prev [-]
		The outdoor CO2 is rising every year. It is not fixed at 400 ppm. The calibrations you speak of are fake. A good sensor can be expected to remain within 10% of reference for ten years.

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OutOfHere 3 hours ago | parent | prev [-]

Not really. For ventilation purposes, a good sensor remain within 10% variation for nearly ten years. We are not running a controlled science experiment here.