I installed a T2 relay and a W100 temperature sensor to control my boiler, all connected to an Aqara M2 hub.
I created automation rules based on the temperature measured by the W100 and the time of day.
Issue
The W100 displays the temperature with a resolution of 0.1°C.
However, the automation rules in Aqara Home only allow temperature values in steps of 0.5°C.
So the trigger thresholds are, for example, 18°C / 18.5°C / 19°C.
Here is how my automation is configured:
Night (23:30 → 05:30)
Turn ON the T2 relay (boiler) if temperature < 18°C
Turn OFF if temperature > 18.5°C
Day (05:45 → 23:00)
Turn ON if temperature < 18.5°C
Turn OFF if temperature > 19°C
The problem
This morning when I woke up (6:20), the heating was OFF.
On the W100 screen, the temperature was 17.7°C.
But in the Aqara Home app, the temperature was displayed as 18.1°C.
As a result, Aqara considered the temperature to be above 18°C, so the heating did not start — even though the real temperature was actually lower than 18°C.
Questions
How can I fix this inconsistency between the W100 display and the Aqara Home app?
Why is there a difference between the temperature shown on the W100 screen and the value processed by Aqara Home?
Is it possible to request a firmware update to modify the temperature resolution used in automations (from 0.5°C to 0.1°C)?
First of all, Best wishes for the year 2026 just starting.
@gafich10, I took the time to read all your recommendations and I understand some points better now
Nevertheless, for me it doesn’t answer to these 2 points :
Why is there a difference between the temperature shown on the W100 screen and the value processed by Aqara Home?
For example, the W100 screen displays 19.5°C, and when I open the Aqara app, the temperature displayed on the card in the home screen is also 19.5°C, but when I check the temperature reading (still in the app by entering the card), it’s 19.4°C. There seems to be a discrepancy between the two displays.
Second point, the W100 is screening the temperature with a resolution of 0,1°C. So I assume it is measuring with the same accuracy. So for example 18,4°C then 18,5°C… But the automation parameters only allow to select a treshold with 0.5°C sensitivity. So for example 19°C or 19,5°C.
Is it possible to request a firmware update or the app settings to modify the temperature resolution used in automations (from 0.5°C to 0.1°C or 0.2°C)?
Regarding the second question, the Aqara app allows you to set only a threshold of 0.5°C, believe me, I have been fighting with developers for more than three years for these 0.5°C. My recommendations are, if you want a range of 0.1°C, in automation set On if more than XX°C and Off if less than XX°C. In W100, set the sensitivity to 0.2°C in the settings.
When the temperature changes by 0.2°C, the information will immediately go to the automation for execution. The peculiarity of this setting is that we can control in increments of 0.5°C (…10;10.5;11;11.5…°C), I think this feature is not very critical for the room.
Set the update time according to the criticality needs (I choose 10 min) of temperature control in the room, this time makes the temperature survey independent, always, with the set period (sends the result to automation). If you set a very short time, the heating boiler will be triggered (On/Off).
