Improving accuracy: Vue readings are 2-5% below what is reported by utility

[meetc0]

My utility has support for Green Button, and can output a XML or CSV with usage data in 15 minute increments, measured in watt-hours (not kilowatt). Home Assistant (by default) only shows 60 minute increments on the energy dashboard, but that's a different topic. I am getting an inconsistent variation between what the utility reports, and what the Vue collects. I have already completed voltage calibration on both phases, and the reported Vue voltage is very accurate compared to that of a multimeter.

Here is a list of total daily usage for July this year. Ignore the discrepancy on July 11 and 14, that was due to downtime of HomeAssistant and/or the Vue

And by hour energy for July 1

Other than the voltage calibration, how else can accuracy be improved for the data collection by the Vue?

[garylankford8]

I could be wrong, but I think this is what I'd try...

Throw out the outliers in your observations and average the percentages (looks like ~2.5%).

In the CT section, where a multiplication factor of 2 is usually applied to 240v circuits, apply a factor of 1.025 to 120v circuits, and 2.050 to 240v circuits.

[meetc0]

Can a multiplier be added to inputs A and B for the mains?

[garylankford8]

Not in the same way, and I don't know how to do it...

Could probably be done with a lambda calculation; something I need to learn!

Sorry I'm not more help.

[flaviut]

You could update the calibration: field you've already updated so that the power comes out to be correct, even if the voltage isn't quite right. If you want the voltage to be correct too then, you could add a multiplier filter on the voltage configs.

But in general I'd say that 2.5% percent is pretty good! I use mine for automations & identifying power hogs, and for that a few percents don't make much of a difference.