@Schlitzkasten1 Hi, Thanks for the suggestion ... I tried and took a picture after a few hours - it improved a bit but I'd say not so much as for the T315's to be considered really useful for now.

add calibration, please

Agree, urgently needed. I got a number of ThermoPro non-smart Sensors around the house and they agree on Temperature and Humidity in any given location ... with the T315s constantly showing 5-10%...