The house is an important motif in "The Rocking-Horse Winner" because it's the symbolic and literal source of the family's monetary anxieties. The house is first mentioned as something that directly represents the idea of superior social status:
[The family] lived in a pleasant house, with a garden, and they had discreet servants, and felt themselves superior to anyone in the neighborhood.
Lawrence here draws a connection between the house and feelings of superiority. Note, crucially, that the house and any other material possessions confer superiority on the family only insofar as the family members themselves believe that those things have power. Paradoxically, the sentence immediately following the one above situates the house as the source of their anxiety, derived from the family's fear than any decrease in income will decrease their social status:
Although they lived in style, they always felt anxiety in the house. There was never enough money. The mother had a small income, and the father had a small income, but not nearly enough for the social position which they had to keep up.
The house is just as capable of lowering the family's "social position" as it is capable of elevating it. Consequently, the house serves as a constant reminder to Paul and Hester of their precarious socioeconomic status. A steady flow of money is required to maintain the house, along with the family's superiority. Throughout the story, the house reappears as a motif and symbol of this class-based anxiety, even whispering to the characters and feeding on their monetary insecurities:
"Our house! I hate our house for whispering."
"What does it whisper?"
"Why? Why?"—the boy fidgeted —"Why, I don't know? But it's always short of money, you know, Uncle."
The intensity of the whispering increases as the story goes on, with the house's presence becoming ever more overbearing. Paul does not seem to know, in the above excerpt, why the house is whispering or when it will stop. He is simply driven to fulfill the materialistic demands of the house, which are not in his own best interest. As the whispering intensifies, Paul is driven to greater and greater extremes to satiate the house's greed, eventually losing his own life in his quest to appease the house's materialistic influence.
