Mat 10:12 And when you enter into an house, salute it.

"Salute" is aspazomai, which means "to draw to one's self." It means an embrace of greeting.

So, when you actually get invited into someone's house, we are to greet and embrace its family members. (The word for "house" is oikia, which means both the physical building and the members of the household or clan.) In other words, we aren't to be stand-offish.