When the Bible speaks about heaven, it speaks of it in different terms.
Many times when the Bible uses the term ouranos, which is a Greek word for “heaven,” it simply refers to the sky. It is also used to describe the dwelling place of God, and that’s a more specific and exalted view of the term heaven.
Now, when we’re talking in Revelation about the new heaven and the new earth, it means that the whole cosmos is going to go through this redemptive process of renovation. Heaven and earth, everything that is, will be renewed by the power of God on the last day. I think that’s the simple meaning of it.