@Giraffe, I use the following query to generate a cumulative kWh graph. The 2380 is an offset to sync up with my electricity meter:
SELECT cumulative_sum(integral("value",1000h)) + 2380 FROM "house_power" WHERE $timeFilter GROUP BY time($__interval) fill(null)
@overeasy, I think the ability to select units is a great addition and looking forward to trying it out! Only suggestion would be to have a mechanism to “sync” the kWh field with the electricity meter reading when required (e.g. on initial installation of the iotawatt or if you get a new electricity meter). Perhaps, allowing to overwrite the last kWh value via the iotawatt UI and have it continue to aggregate and publish from that value onward would work?
As a side note, the drift against meter has only been around 0.4% over the last 6 months which is pretty good in my book!