I have 3 sonoff humidity/temp sensors and, like in the article, the temperature is very accurate but the humidity is way off. I compared them with each other, with our TADO system and a non-smart simple weatherstation.
I would not buy them if you plan to use it as a humidity sensor.
To be clear, other sonoff devices are well worth the money imo.
I have a few of them and are in the process of replacing them. They tend to fall off the zigbee network and even worse, the reset button is so filigree that it easily breaks if you push it too hard. I can not recommend the Sonoff SNZB-02 if you are after reliability and durability.
I have moved to the Xiaomi Mijia Temperature/Humidity sensors LYWSD03MMC (replaced 5 SNZB-02’s so far) but converted them to Zigbee. Those are cheap and working well as end devices within the Zigbee network but they have screens.
Since most people are wondering how battery life is affected on the Zigbee firmware compared to the original BLE firmware, developer pvvx wrote a short paragraph explaining his findings:
“The final average consumption of LYWSD03MC B1.4 when measured from a 3.3V source is from 14 to 26 µA, depending on the dynamics of changes in temperature and humidity. For comparison, the BLE version consumes 14 µA with default settings and constant transmission of all measured values every 10 seconds.”
It’s safe to say that even though battery consumption is higher on the Zigbee firmware, in reality it will be affected very little compared to the default setting of the BLE version.
Take notice there that Zigbee Coordinator and devices is extremely sensitive to EMF.
I suggest still buying a Zigbee Coordinator USB adapter instead and buying USB over Cat6 conversion adapter kit that will convert any shielded Ethernet cable into a very long USB extension cable as that can be easier to maintain and upgrade when needed (plus the conversion adapters are dumb so less chance to break), check out these and similar for example: