I don't have my meter connected yet, but I did an experiment. I don't have battery or loads connected. Only solar and grid connected. Back feeding to grid.
I waited until solar production was just under 100W. It showed that the inverter was using power from the grid. However, when I turned off the grid, the inverter continued to work on solar only. The fans were running at the same speed for a while until the sun went down more.
So I think it's using under 100W. I guess I'll know for sure when I can get my meter running. In my opinion, anything over 50W is a lot. That's over 1kw per day at 50W already