Two more texts in John, both of which inform us of nearly the same thing:
12:27 ?Now my heart is troubled, and what shall I say? ?Father, save me from this hour?? No, it was for this very reason I came to this hour. 28 Father, glorify your name!? Then a voice came from heaven, ?I have glorified it, and will glorify it again.? 29 The crowd that was there and heard it said it had thundered; others said an angel had spoken to him.
17:1 After Jesus said this, he looked toward heaven and prayed: ?Father, the time has come. Glorify your Son, that your Son may glorify you.
God the Father is in heaven.
Out of heaven God speaks.
Jesus looks up to heaven when he prays.
One of the most common uses of “heaven” is to refer to “up-ness” and I would think this is metaphorical for the Beyond and The Most High One. There is a spatial-ness about this kind of language. I think it entirely possible that this would refer to a “place” but that word might not be transcendent enough to do the word “heaven” justice. Space, yes, and much more.
But, notice too in John this theme: it is the place out of which God’s Voice comes and out of which God exits in order to descend into the earthly realm.