Wolferl, that is not acceptable. Our Gaslab 501, IQ Air Visual Pro ($239) and AWAIR Element ($149) all provide accurate CO2 readings that are in agreement with each other and that properly compensate for temp changes. Your readings are off by multiple 100’s of PPM, not just 50 or 5%. Your device costs 2x to 4x more than these others, it should be better, not worse.

“…one never knows” – YOU should know. You are the manufacturer.

“that sensor performs some magic self calibration”. Some magic? You are the manufacturer of a device that you are selling. You should fully understand exactly what your vendors are doing. Others who use this same sensor are getting accurate results from it, why are you not?