The part from the post that answers your question is this:
The sensing platform used is a Sensirion SEN63C, which uses a STCC4 for CO₂ measurements. Unfortunately, this is not an NDIR sensor. Instead it uses less accurate thermal conductivity sensing. This allows building smaller/cheaper sensors, but it depends on the input of the temperature/humidity sensor, because e.g. humidity influences measurements. Also, the sensor relies on the air mixture being 78% N₂, 21% O₂, 0.93% Ar, 400 ppm CO₂ and will stop giving accurate readings when this composition changes (modulo CO₂). The operating conditions are also more limited than most other CO₂ sensors (10–40 °C, 20–80% RH).
From what I could gather and what is also mentioned in the conclusion is that the sensor is fine to get a general feeling of the CO2 trends, but that you're better off getting a better sensor if you care about exact values.
Oh, that's a shame :(
Similar to when I bought a TVOC sensor that claimed to have CO2 as well. Until I realized it was eCO2 which is pretty much useless because it just guestimated based on TVOC counts.
The part from the post that answers your question is this:
The sensing platform used is a Sensirion SEN63C, which uses a STCC4 for CO₂ measurements. Unfortunately, this is not an NDIR sensor. Instead it uses less accurate thermal conductivity sensing. This allows building smaller/cheaper sensors, but it depends on the input of the temperature/humidity sensor, because e.g. humidity influences measurements. Also, the sensor relies on the air mixture being 78% N₂, 21% O₂, 0.93% Ar, 400 ppm CO₂ and will stop giving accurate readings when this composition changes (modulo CO₂). The operating conditions are also more limited than most other CO₂ sensors (10–40 °C, 20–80% RH).
From what I could gather and what is also mentioned in the conclusion is that the sensor is fine to get a general feeling of the CO2 trends, but that you're better off getting a better sensor if you care about exact values.