Completely erroneous measurements

Holder of a module AND a Netatmo Netatmo additional module, I placed the two in the same room ... and I found huge differences between the two (and not always in the same direction).
Ex:
- Ventilated room: Module 1 indicates 407 ppm CO2, the module 2 indicates 453 ppm CO2.
(!): - Unventilated room module 1 indicates 2435 ppm CO2, the module 2 indicates 1283 ppm CO2.

The same variations were observed for moisture (ie 41% vs 84% ​​in the same room at the same time) and temperature (19.5 ° versus 20.3 °).

I contacted the SAV Netatmo, they said that this was due to "degassing of new materials from the factory" and I had to wait a few weeks as the situation stabilizes ... After 2 months, the situation worsened.

In short, it is VERY far from a margin of error of 5% as announced by the manufacturer. This is actually a useless gadget. Back to Amazon and reimbursement.

My advice: do not buy especially not this.