Please also read the critical reviews

I bought the station, because the predominant assessments are positive. I bought the station plus additional internal module and then release to send a replacement unit another station, the "defective" but has not yet returned. (Prima that this is all so possible on Amazon). I have therefore since 2 weeks 1 indoor station and 1 entry panel and since yesterday 2 stations and 1 internal add-on module (ie 3 indoor stations) and 2 outstations in the observation. I made a lot of negative experiences that made Chris and Wupper world.

In a nutshell:
For me the two outstation run correctly, ie they show almost exactly the same values ​​and are plausible.

The indoor stations disastrous deviations from each other (temperatures about 1 degree (21.3 instead of 20.4), humidity over 10% (ie 51% instead of 40%), CO2 more than 250 units, so for example, 290 and 540). That CO2 difference when the air is bad is sometimes higher (1.600 and 2.100))

My Conclusion:

a) The stations are pretty and very nice apps. The whole thing is fun and you can see the development of temperature and CO2 during the day.
b) The built-in sensors of the indoor stations are definitely bad and so are the values ​​definitely wrong
c) As the tendency statements stations naturally useful (if you want to know when to ventilate again)

Oh yes: The technological dependence should not go unnoticed. My WiFi is my failed due to a defect. During this time I had none of the station. If the manufacturing company go bankrupt, the stations are also worthless.

Unfortunately, there is nothing like it is from another manufacturer and I have found nothing.