VOLTCRAFT Energy - Logger 4000, this is another portable (plug-in) energy meter.
This is not new released product, it appears to be in the market of
north Europe since 2010.
Even so, by reading it specifications, this is the only product which it does mention accuracy at low watts.
5 - 3500 W (±1% + 1 count)
2 - 5 W (±5% + 1 count)
< 2 W (±15% + 1 count)
In theory this is capable to measure
0,1 - 3500 W.
Most other similar gadgets they mention 1W as lower value.
The interesting part is that VOLTCRAFT 4000 at video reviews, this appears to have very insensitive Power Factor measurement at 5W and below.
I am not willing to get this product and review it, for the discovery of actual limits at measuring low watts, mostly because distribution and sales are limited to Conrad, an German based super store.
But if you do own one?
Then feel free, to share with us, your thoughts of how this meter behaves at 5W and below.
VOLTCRAFT energy 4000, this is capable to store measurements over SD card, and therefore if you have export low watts measurements to MS Excel file, this is able to demonstrate measuring limits about Power Factor at highest detail.