Meanings
Usage patterns
お宅はどちらですかa polite way to ask where someone lives
Excuse me, but where do you live?
お宅にお邪魔するto visit someone's home (polite)
Would it be all right if I visited your home tomorrow?
お宅は何人家族ですかa polite way to ask how many people are in someone's family
How many people are there in your family?