I was not frightened by Hell House. To instill horror, the novel depends largely on the transgression of sexual mores. Those mores seem quite outdated to this reader in 2016. There are already many excellent reviews that make the same point, so I'll say no more on that topic.
I gave Hell House two stars because of Matheson's craftsmanship. It's built to last with solid joinery and thick coat of polyurethane. It's too bad that it elicits no more emotion than would a chest of drawers.