How have house prices and mortgage rates changed monthly payments?
Core argument: Inflation-adjusted U.S. house prices stand 2.7% below their 2022 peak, based on the Case-Shiller National Index, seasonally adjusted.
I’ve put together my own affordability index [using] median income from the Census Bureau (estimated 2024 and 2025), assumed a 15% down payment, and used a 2% estimate for property taxes, insurance and maintenance. This is probably low for high property tax states like New Jersey and Texas, and too high for lower property tax states. For house prices, I used the Case-Shiller National Index, Seasonally Adjusted (SA). Also, for the down payment - there wasn’t a significant difference between 15% and 20%. For mortgage rates, I used the Freddie Mac PMMS (30-year fixed rates). Here is what the index looks like (lower is more affordable). In July 2021, the payment on a $500,000 house, with a 20% down payment and 2.87% 30-year mortgage rates, would be around $1,658 for principal and interest. The monthly payment for the same house, with house prices up 24% over four years and mortgage rates at 6.72% in July 2025, would be $3,218 - an increase of 94%! Almost double the payment for the same house!

