Special Studies January 2, 2019
By Na Zhao, Ph.D
NAHB Economics and Housing Policy Group
Report available to the public as a courtesy of HousingEconomics.com
This article announces NAHB’s “priced out estimates” for 2019, showing how higher home prices and interest rates affect housing affordability. The 2019 U.S. estimates indicate that a $1,000 increase in the median new home price would price 127,560 U.S. households out of the market. In other words, 127,560 households would qualify for the new home mortgage before the change, but not afterwards. Similarly, 25 basis points added to the current mortgage rate would price out around 1 million households. The article also includes priced out estimates for individual states and more than 300 metropolitan areas.
The Priced Out Methodology and Data
The NAHB Priced Out model uses the ability to qualify a mortgage to measure housing affordability, because most home buyers finance their new home purchase with conventional loans,  and because convenient underwriting standards for these loans exist. The standard NAHB adopts for its priced-out estimates is that the sum of the mortgage payment (including the principal amount, loan interest, property tax, homeowners’ property and private mortgage insurance premiums (PITI), is no more than 28 percent of monthly gross household income.
As a result the number of households that qualify for mortgages for a certain priced home depends on the household income distribution in an area and the mortgage interest rate at that time. The most recent detailed household income distributions for all states and metro areas are from the 2017 American Community Survey (ACS). NAHB adjusts the income distributions to reflect the income and population changes that may happen from 2017 to 2019. The income distribution is adjusted for inflation using the 2018 median family income published by the Department of Housing and Urban Development (HUD) for all states and metro areas, and then extrapolated it into 2019. The number of households in 2019 is projected by the growth rate of households from 2016 to 2017.
The assumptions of the priced out calculation include a 10% s down payment and a 30-year fixed rate mortgage, at an interest rate of 4.85%. For a loan with this down payment, private mortgage insurance is required by lenders and also included as part of PITI. The typical private mortgage insurance annual premium is 73 basis points, based on the standard assumption of national median credit score of 738 and 10% down payment and 30-year fixed mortgage rate. Effective local property tax rates are calculated using data from the 2017 American Community Survey (ACS) summary files. Homeowner’s insurance rates are constructed from the 2016 ACS Public Use Microdata Sample (PUMS). For the U.S. as a whole, the property tax is $12 per $1,000 of property value and the homeowner insurance is $4 per $1,000 property value.
Under these assumptions, 32.7 million of the 122.5 million U.S. households could afford to buy a new median priced home at $355,183 in 2019. A $1,000 home price increase thus would price 127,560 households out of the market for this home. These are the households that can qualify for a mortgage before a $1,000 increase but not afterwards, as shown in Table 1 below.
State and Local Estimates
The number of priced out households varies across both states and metropolitan areas, largely affected by the sizes of local population and the affordability of new homes. The 2019 priced-out estimates for all states and the District of Columbia are shown in Table 2 (available in the Additional Resources box), which presents the projected 2019 median new home price and the amount of income needed to qualify the mortgage, and the number of households could be priced out if price goes up by $1,000. Among all the states, Texas registered the largest number of households priced out of the market by a $1,000 increase in the median-priced home in the state (11,152), followed by California (9,897), and Ohio (7,341).
Table 3, which is available in the Additional Resources box, shows the 2019 priced-out estimates for 382 metropolitan statistical areas. The metropolitan area with the largest priced out effect, in terms of absolute numbers, is Chicago-Naperville-Elgin, IL-IN-WI, where 4,598 households are squeezed out of the market for a new median-priced home if price increases by $1,000. This is largely because Chicago is a populous metropolitan area with a large number of households; and, compared to the largest metropolitan areas on the East and West costs, the median priced home is more affordable to begin with. Around 26% of households there are capable of buying new median-priced homes. For similar reasons, Houston-The Woodlands-Sugar Land, TX metro area, where nearly 32% of households can afford median-priced new homes.to begin with, registered the second largest number of priced out households (3,622). In New York-Newark-Jersey City, NY-NJ-PA, 3,613 households are squeezed out of the housing market for a new median-priced home if price increases by $1,000. Compared to Chicago or Houston, the median-priced new home is affordable to a smaller share of the households in New York, but New York is the largest metro area by population size with over 7 million households.
The NAHB 2019 priced-out estimates also present how interest rates affect the number of households would be priced out of the new home market. If the mortgage interest rate goes up, the monthly mortgage payments will increase as well and therefore higher household income thresholds to qualify a mortgage loan. Table 4 shows the number of households priced out of the market for a new median priced home at $355,183 by each 25 basis-point increase in interest rate from 2.85% to 10.85%. When interest rates goes up from 2.85% to 3.10%, around 1.26 million households could no longer afford buying median-priced new homes. An increase from 4.85% to 5.10% could price approximately one million households out of the market. However, about 423,000 households would be squeezed out of the market if interest rate goes up to 10.85% from 10.6%. This diminishing effects happen because only a few households at the thinner end of household income distribution will be affected. On the contrary, when interest rates are relatively low, 25 basis-point increase would affect a larger number of households at the thicker part of income distribution.
According to the 2017 American Housing Survey (funded by HUD and conducted by the Census Bureau), 74 percent of the home buyers who moved into their homes in 2016 or 2017 had a regular primary mortgage on the home.
Producing metro level estimates from the ACS PUMS involves aggregating Public Use Microdata Area (PUMA) level data according to the latest definitions of metropolitan areas. Due to complexity of these procedures and since metro level insurance rates tend to remain stable over time, NAHB revises these estimates only periodically.