ᐅ Weather Stations with Multiple External Sensors?!

You put it clearly and precisely as usual :-). I also noticed the variations in relative humidity; according to reviews, it seems a bit of a lottery whether your own Netatmo measures reasonably accurately or not. For that reason, I find it far too expensive!

Netatmo would be nice in terms of functionality, though:
- Temperature
- Relative humidity
- CO2
- Precipitation
- Wind (which isn’t important to me personally)
- All of this both indoors and outdoors

Other disadvantages: apparently(?) it runs through a Netatmo server. Does it require a constant internet connection? That’s not clear to me yet, and that would be for me another reason to exclude it.

The Klima Logg Pro from TFA seems more reliable at first glance. I haven’t fully understood yet how it records outdoor data.

I am also looking for a reliable sensor for room temperature and humidity. I have already tried several inexpensive devices, but the deviations were always quite extreme. However, I do not believe that higher prices automatically guarantee better accuracy.

Bieber0815 schrieb:

Klima Logg Pro by TFA seems more reliable at first glance. I haven’t quite understood yet how the outdoor unit records data.

I simply placed one of the external sensors outside on the balcony (I’m aware that near the wall it’s usually a bit warmer than on the ground in the garden). The sensors transmit data wirelessly to the display unit. The display unit also has built-in sensors that show the data for its own location. The external devices alternate between showing temperature and humidity on their own display and send data to the display unit at regular intervals.

You can set how often these values are saved on the display unit, for example every 5 minutes. The shorter the interval, the more detailed the data resolution that can be later transferred to a PC.

Regarding the accuracy of humidity measurement: I tested all 8 of my external sensors side by side in the same spot. Only one external sensor showed a deviation of about 3% in humidity; all the others displayed almost the same value after a short acclimatization period. Whether the absolute values are correct, I can’t say, but that wasn’t very important to me. The fact that almost all values were consistent indicates that the devices are reasonably well calibrated when delivered. For higher accuracy, you’ll probably need to invest more money.

One more tip: I bought a second set later, which was cheaper than purchasing four external sensors individually. This way, I still have a spare display unit that I’m not currently using. Of course, you could also set it up at another location and pair sensors there, so you would have two display units running in parallel.

The best and most accurate devices are probably still those that use chemical "tricks" (e.g., temperature measuring units with mercury).

It is clear that a high price is not a guarantee that the devices measure properly. However, it is basically unacceptable to spend money on attractive aesthetics instead of ensuring the actual functionality. A 10% deviation in relative humidity is not measuring but guessing.

Payday schrieb:
The best and most accurate devices are probably still those that use chemical "tricks" (for example, temperature measuring units with mercury).

Apparently not, how do you come to that conclusion? Stiftung Warentest tested hygrometers back in 2003 and found that electronic devices are generally superior because mechanical ones are often not properly calibrated. Among the electronic devices, the measurements of 5 out of 7 tested units were good.
Although the test is quite old and I can’t say whether the results still apply today, the trend often points to cheap, low-quality products, which probably also applies to mechanical devices. There are various websites claiming to have tested hygrometers, but how reliable those are is questionable... Often the devices from TFA rank among the better ones. And whether Amazon reviews provide more clarity is also doubtful.
At least I am satisfied with my devices and am aware that they are not really intended for scientific or expert use. For that, you would have to look at brands like Fluke or similar, where you can find something for higher demands—but those are not weather stations.

I am very satisfied with Netatmo. I have good access to all measured data on all mobile devices. The most important feature for us has become the CO2 measurement. Paired with a Hue lamp, it signals when it is time to ventilate again. At a level of 1300 ppm, a lamp starts glowing red. Really practical.