Final answer:
PITH in housing expenses stands for Principal, Interest, Tax, and Heating, representing the full monthly cost of owning a home.
Step-by-step explanation:
When calculating a borrower's comprehensive monthly housing expenses, PITH stands for Principal, Interest, Tax, and Heating. These components are essential to understanding the full cost of home ownership beyond just the mortgage payment itself. The principal and the interest make up the mortgage payment, tax refers to property taxes, and heating covers the cost of heating the home, which is necessary to consider in areas where heating expenses can significantly impact monthly housing costs.