Bradbury describes the bedroom as a mausoleum. How is this description appropriate?

The author wants to describe Montag's house and his relationship with Mildred as cold.

It was like coming into the cold marbled room of a mausoleum after the moon had set. Complete darkness, not a hint of the silver world outside. The windows tightly shut, the chamber of a tomb-world where no sound from the great city could penetrate.

The feeling of coldness is a metaphor for how cold and detached Montag's life is.