It’s a sensor. There is no way to know if it’s on or off. Pretty sure state_color only works for binary type devices, like switch/light/binary_sensor, etc since those all are forced to return either true or false.
@jocnnor hi and thanks for your reply. But if it is no way of knowing if it is ‘on’ or ‘off’ why then does show_state: true work exactly as it should ?
Because it will show the state. It doesn’t care if the state is ‘on’, ‘off’, ‘the_climate_is_on’, ‘Please Fasten Your Seatbelts’…it’s always just a text string. It doesn’t try to translate the state string to a boolean.