Acts 20:20 HAS to mean "in private homes." The context shows that Paul is discussing his teaching of the elders of the Ephesian church. Nothing in the passage suggests anything about a door-to-door proselytizing work. In verse 20, Paul writes, "You know that I have not hesitated to preach anything that would be helpful to you but have taught you publicly and from house to house." The "you" is shown by verse 17 to be the elders; not the regular church members, not the general public. He taught them "from house to house" by visiting the various private homes of the elders, not by going up the street knocking on doors. Unless the Witness is willing to take the position that Paul found a neighborhood, started going down the street knocking on every door until he found an elder of the church and then taught him, there is no warrant whatsoever for using this verse in support of a house-to-house ministry such as that of the JWs.