They monitor what is the lowest CO2 ppm value read and assume this is 400 ppm. This is processed in 8 days cycles, where the lowest ppm value from the previous period is used for the current.stefxx wrote: One question: how accurate are your sensors (how are they calibrated)?
The sensor is electro chemical and according to the spec the error they give is +- 15-20% . When i was measuring them against a K30 CO2 sensor, it was even better. But it all depends on how correct the baseline has been computed. here you can read some more details in case you are interested
I am currently researching some new "cheap" (<40 eur) NDIR sensors that promise error <5%, but i am still in the research phase. The last i tried from another company (MH-Z19) was crap. In case it turns out they work fine it will be great