There's a misunderstanding here that needs some attention.
'My Father's house' is not in heaven. Jesus says so:
John 2:16 And said unto them that sold doves, Take these things hence; make not my Father’s house an house of merchandise.
Clearly, this is the temple.
Isaiah and others agree: The house of God is the temple of the Lord:
2 And it shall come to pass in the last days, that the mountain of the LORD’S house shall be established in the top of the mountains, and shall be exalted above the hills; and all nations shall flow unto it.
3 And many people shall go and say, Come ye, and let us go up to the mountain of the LORD, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem.
The location is also given, you notice: Jerusalem, both in the gospels and in Isaiah 2.
Jesus' words are:
2 In my Father’s house are many mansions: if it were not so, I would have told you. I go to prepare a place for you.
He is GOING: which means, dying.
By his sacrifice, the place of His disciples (those who believe in Him as Jn 14.1 says) in the house of God is prepared.
3 And if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also.
When He comes again, where will He be? On the earth, of course. So where are we going to be? On the earth as well, because 'the meek shall inherit the earth'.