I've always held that the occupant of a building must be the one to invite, not the owner.

Reasoning: vampyric stories have been around since monarchies and nobility were the standard for landowners. The people in houses all over the kingdom didn't own the houses or land, that belonged to some lord somewhere.

So since the people still had to be wary of inviting in strangers. The vampire could enter if they, the occupant (but not owner) invited them in.

Your best bet is to just stab everyone who asks to enter with a silver crucifix-stake dipped in garlic and holy water.