BME680 sIAQ and CO2 sudden permanent increase

[Sepro]

I've been running an BME680 in combination with an esp8266 and esphome for a few months, which had been giving me very plausible estimated CO2 and (static) IAQ levels. However, since a few days both appear way off, even next to an open window CO2 levels would be 1400 ppm and IAQ well over 200, which used to be 500 ppm and ~35 IAQ.

Any thoughs what might have caused this sensor to be thrown off, and suggestions how to mitigate this ?

How far back go the reference values for calculating the sIAQ (is that the 28days in the config filename ?)?

[BSTRobin]

Hi Sepro,

Thanks for your inquiry.

The completion of IAQ backend calibration takes time, and the calibration time depends on the configuration you are using. For example, generic_33v_3s_28d, the backend calibration time will take 28 days.

In addition, when you check the IAQ and CO2 output, you can also check the calibration accuracy value to see whether the calibration is currently completed or in progress.