Energy usage without sensors


I don’t have sensors that measure energy. But I often do know how much individual bulbs use.
Is there a way I can say f.e. “the group kitchenlight uses xxx energy when on”?

And in the same avenue; I don’t have anything to follow up my meters. But I could enter them on an (ir-)regular basis into a spreadsheet of some sort to be able to track my usage? is there a solution for this?

Thank you

For the first:

For the second you can enter the value in in an input number that is then monitored by a template sensor.