Although it can be done easily with a template (as the other options), it would be a good idea to add difference as a new option to “Combine the state of several sensors” helper.
For instance, it can be used to substract the power or energy of a appliance to the general one to distinguish its use from the rest of the charge.
definitely could use this…
would make creating new sensors a breeze for noobs out there.
Great example is Enphase Solar. You must create a sensor subtracting the Production from Consumption and Vise Versa then take the result (watts) and convert to kW in order to use in the dashboard.