[K2h]

If you try to measure CO2 usage, be aware of the fineprint in your sensor, depending on the sensor it may just take the lowest reading over some period and self calibrate (incorrectly) as normal air CO2 concentration (~400ppm)

<https://www.extech.com/products/CO240>

Automatic CO2 Baseline Calibration (ABC) The ABC algorithm continually tracks the sensor’s lowest reading over a fixed time interval and slowly corrects for any long-term drift (as compared to the expected fresh air value of 400ppm). The ABC period is 15 days, during which the ABC function default is always on.