I have set three ground rules for this list:
a. The horror is either supernatural or its precise nature is left open to interpretation – nothing clearly caused by people and their madness alone. This rules out works like A Rose for Emily, Northanger Abbey, Jane Eyre, Rebecca, Great Expectations, and The Yellow Wallpaper.
b. The story has to take place in an actual house; no Castle of Otranto or The Shining.
c. The house is the main setting of the story and/or the horror in question is tied to the house in some way.