The other comment is correct, but I was going to add additional evidence. I'm fairly certain in Official Vampire Lore*, it has to be someone who lives in the house to invite them in. Otherwise the vampires would just send Renfield in and have him invite them inside.
*Buffy, Season 5, Episode 2.
In related news, the people who said we shouldn't cut down all of the American Chestnut trees when they got a blight were absolutely right, but were overruled by capitalism.