Is it important the the reading is precisely correct for my use? It doesn't seem so. How do you know your thermometer is calibrated? Your thermostat? Your spee

Is it important the the reading is precisely correct for my use? It doesn't seem so. How do you know your thermometer is calibrated? Your thermostat? Your speedometer? Did you have your computer monitor calibrated by a professional? The CO2 meter has a self-calibration function that I've used that calibrates it to the baseline known outdoor PPM. Indoors, it is clearly responsive to the environment. And the readings correlate with noticeable changes in air quality. The primary interesting part about it is that it gives a clear indication of how long it takes for the air in the house to be exchanged by the vent fan and return to the outdoor PPM. I don't see how precise calibration really matters for this use case.