That's a bit unreliable calibration, mean CO₂ are... mean... Witch means that might vary more than a bit from here to there... With no knowledge about how such

That's a bit unreliable calibration, mean CO₂ are... mean... Witch means that might vary more than a bit from here to there... With no knowledge about how such sensors works internally, my VMC have an optional CO₂-monitoring-driver to automatically regulate the fan speed: even the vendor state it's not worth the money, it might spare few € in electricity but not more.