One of the comments says, it does effect the electric company (why shouldn't it, energy does not come out of nowhere) and they can meassure it.

"Velemu says: There was one case in Finland in The 90s, where someone did this to power their summer cottage. When Power company found, where the extra parasitic load came from, they sued the guy to hell and back again. This kind of load is actually actively measured by Power companies, since it is also used to find other failure modes on powerlines, and is easy to detect. Just don’t do it…."