Where to install the temperature sensor and others in the house?

Question

Smart House

I read thematic articles and forums, in most cases it is advised to install the temperature sensor at a height of 1.5 m from the floor, away from windows, doors, heating radiators and from light sources.
In August (without heating) and in December (with heating), I measured the temperatures in the apartment with three different thermometers (1 electronic from Ali, 2 non-electronic from the local market).
Depending on the altitude and location, the difference in temperature was 2.3, 2.9 and 3.1 degrees for the three instruments. At a level of about 5 cm from the floor, the lowest temperature, at a height of 2-3 cm from the ceiling, the highest. At a height of 1.5 m, everyone shows the same temperature (taking into account the error of each, the difference in the readings was 0.5 g; acceptable).
There is also a difference at different distances from the wall: close, 3-4 cm, 1 m. The temperature is lower near the wall, closer to the center of the room it is warmer. I think the wall gives off its cold. There is a time difference. All this is quite logical from the point of view of the laws of physics.
Before the experiment, I planned to install temperature sensors next to sockets or a light switch in a plastic case. The opinion of those who already use temperature sensors at home is interesting. No less interesting is the installation location for humidity, light (and pressure) sensors.
Added: The house will have underfloor heating.

Answer 1

Usually they are installed at a height of about 1.5 meters, only it is necessary that there are no devices that emit heat / cold nearby, and also do not put in a draft - so that the readings do not jump

Answer 2

just an article on the installation of the sensor