First, verify that the installation is done correctly (see installation instructions in this section).
If Smart Valves are installed in unfavorable positions (e.g. vertically on the top of the radiator, covered by curtains, next to recesses or heating sources), the detected temperature might be affected by errors.
Therefore, you can set an "offset" (temperature difference of 0°-5° less) through the app, by selecting "Menu --> Devices --> Smart Valve": then, select the valve in the room by clicking on it and click on "Optimisations - Offset".