The book of Acts:
Acts 2:2
And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting.
At first, though they met in the Jewish temple (until thrown out), they celebrated as Christians from house to house,
Acts 2:46
And they, continuing daily with one accord in the temple, and breaking bread from house to house, did eat their meat with gladness and singleness of heart,
Acts 5:42
And daily in the temple, and in every house, they ceased not to teach and preach Jesus Christ.
When Saul (before he became Paul) sought to persecute Christians he knew where he could find them...in their houses.
Acts 8:3
As for Saul, he made havock of the church, entering into every house, and haling men and women committed them to prison.
Acts 9:11
And the Lord said unto him, Arise, and go into the street which is called Straight, and enquire in the house of Judas for one called Saul, of Tarsus: for, behold, he prayeth,
Acts 9:17
And Ananias went his way, and entered into the house; and putting his hands on him said, Brother Saul, the Lord, even Jesus, that appeared unto thee in the way as thou camest, hath sent me, that thou mightest receive thy sight, and be filled with the Holy Ghost
Acts 10:9
On the morrow, as they went on their journey, and drew nigh unto the city, Peter went up upon the housetop to pray about the sixth hour:
Acts 10:22
And they said, Cornelius the centurion, a just man, and one that feareth God, and of good report among all the nation of the Jews, was warned from God by an holy angel to send for thee into his house, and to hear words of thee.
Acts 12:12
And when he had considered the thing, he came to the house of Mary the mother of John, whose surname was Mark; where many were gathered together praying.
Acts 20:20
And how I kept back nothing that was profitable unto you, but have shewed you, and have taught you publicly, and from house to house,
Acts 28:30-31
And Paul dwelt two whole years in his own hired house, and received all that came in unto him,
Preaching the kingdom of God, and teaching those things which concern the Lord Jesus Christ, with all confidence, no man forbidding him.