How does Scrooge's greed cause his loneliness?

The wealthy Scrooge lives in miserable circumstances in a cold abandoned building that is dark because he does not want to spend money on candles ("darkness was cheap, and Scrooge liked it"). His wealth is not bringing him any more happiness—it only perpetuates the fear that one day he will lose it. Scrooge rebukes the people in his life that want to give him warmth and love like his nephew Fred.