they have to make adaption to my old electric system at home and do some digging to find the acces point outside and than pull an electric cable to my electric cabinet inside..
Ah okay.
If they have to "update" you whole electrical system, then that's another factor.
Maybe really think about it, if it is not worth to update your building's electrical system now, because in the future you may have to do it anyways if you add other big electrical devices (air condition system or heat pump)