June Heiress lives in a beautiful house that she inherited from an indulgent aunt, and on which she has no mortgage. The house is indestructible, and will last forever. A similar house across the street recently sold for $500,000.
Another house next door was rented for a year for $20,000. The bank down the street pays 5% interest on savings deposits.
Aside from utilities, taxes, and maintenance, what is the cost to June of living in this house for a year? Explain in one or two sentences.