Lets make sure we’re all on the same page here. I don’t believe the switches themselves are actually consuming that much power. The problem, IMO, is the value it reports which is not necessarily a super-accurate number … especially at lower power levels. It doesn’t have milliamp accuracy.
And that right there basically supports my previous statement that the reporting is wrong at very low power levels and the switches are not consuming 40kWH per every month for every switch. Common sense says that smart switches would not be consuming 20% of your total electric bill.
That is the problem. Low level power reporting is not accurate without specialized hardware. The power sensing hardware in smart switches is intended for sensing higher loads in the 50w-500w range, NOT the low level 5mW-50mW range that the internal switch electronics use.
For the sake of this discussion, I hooked up a LZW31 Black Dimmer (don’t have a spare Red at the moment) on my test bench with a kill-a-watt type of device which is not particularly a super accurate device, but its capable of measuring as low as 0.1w and its reporting 0.3w for just the switch itself (no load, no bypass) and that comes to 0.22kWH per month. Where I live ($0.11/kWH) that’s only 2.4 CENTS per month - no where near the $9-$10 per month that some of you estimated.
I believe there is something in the hardware/firmware that imposes a lower-limit on the power reporting. For my Inovellis that number seems to be 1.6W. That’s the lowest value it reports for me under any conditions, but I’m confident the actual power consumption of the switch itself is less than that. I’m not saying 0.3W is the most accurate number, but I do believe its a lot closer than the 1.6w-2.3w that the switch is reporting with no load.