@BastianWag 

Given the working principle of the Kasa thermostat valve, its heating state may be challenging to use as a smart action trigger, at least from my point of view. The valve regulates the temperature by controlling the flow of hot water. Unlike a heater, which has a one-time on/off operation, the valve operates intermittently and continuously. 

It aims to keep the temperature stable by gently opening and closing the valve. If it completely turns off when reaching the set temperature, it may lead to a significant temperature drop, requiring more energy for re-heating.