Researchers, investors, and policymakers need reliable housing affordability data to understand market conditions and make informed decisions. Whether you’re tracking price-to-income ratios, rent burdens, or mortgage-payment metrics across regions, the right data sources provide the foundation for credible analysis. This guide covers 10 of the most widely used and trusted housing affordability data sources available today.
Each source offers different geographic granularity, update frequency, and measurement approaches—from broad national indices to city-level comparisons. Knowing which source fits your research question is key to drawing accurate conclusions about housing conditions.
Quick Overview List
- National Association of Realtors (NAR) Housing Affordability Index — A monthly index measuring whether typical families can afford median-priced homes at national and regional levels.
- NAHB/Wells Fargo Cost of Housing Index (CHI) — A quarterly measure showing what percentage of family income is needed for mortgage payments on median-priced new and existing homes.
- Zillow Research (ZORI and ZHVI) — A comprehensive rent and home value tracking system offering asking rent indices and affordability metrics at multiple geographic scales.
- American Community Survey (ACS) — The Census Bureau’s annual survey capturing home values, rents, housing costs, utilities, and cost-burden data nationwide.
- HUD’s Comprehensive Housing Affordability Strategy (CHAS) Data — Custom Census tabulations showing housing problems and needs by income level, updated annually.
- American Housing Survey (AHS) — A biennial Census Bureau survey (HUD-sponsored) with comprehensive data on housing conditions, costs, and demographics.
- FRED (Federal Reserve Economic Data) — An economic database hosting NAR housing affordability indices, mortgage rates, and other housing-related time series.
- HUD’s Homebuyer Affordability Index — A ratio-based measure of median income to the income needed to afford a median-priced home in a given area.
- Joint Center for Housing Studies (JCHS) — Harvard-based research center publishing annual State of the Nation’s Housing reports with affordability analysis and trend data.
- Ocity.org Housing Affordability Index — A city-level ranking of 500+ U.S. cities using price-to-income ratios and rent-burden metrics from Census and Zillow data.
1. National Association of Realtors (NAR) Housing Affordability Index
What it is
The NAR Housing Affordability Index is a monthly measure that indicates whether a typical family earns enough income to qualify for a mortgage loan on a typical home. It’s calculated at the national level and for select regions, based on the most recent price and income data. An index value of 100 means a family with median income has exactly enough income to qualify for a mortgage on a median-priced home; above 100 signals better affordability.
Why it matters
- Most widely cited affordability metric in real estate publications and news coverage.
- Offers monthly updates, making it responsive to market shifts in mortgage rates and home prices.
- Available at national and regional levels, enabling side-by-side market comparison.
- Long historical data (decades) allows trend analysis and cyclical pattern identification.
How to use it / Key details
Access NAR data directly through their research portal or via FRED. The index assumes a 20% down payment and uses mortgage rates from Freddie Mac’s Primary Mortgage Market Survey. Note that NAR discontinued composite indices (mixing fixed and ARM rates) in 2019, so you’ll now find fixed-rate-only versions. Use the data for quick market snapshots or to track whether affordability improved or declined month-to-month or year-over-year.
2. NAHB/Wells Fargo Cost of Housing Index (CHI)
What it is
The NAHB/Wells Fargo Cost of Housing Index is a quarterly measure that expresses mortgage payments as a percentage of a typical family’s pre-tax income. A CHI reading of 32% means a typical family must allocate 32% of income to cover the mortgage payment on a median-priced home. It covers both new and existing homes at the national level, and existing homes in 175 metro areas.
Why it matters
- Offers a more intuitive interpretation than other indices—straightforward percentage format.
- Includes a low-income variant (families earning 50% of area median income) for vulnerable populations.
- Covers metro-level detail, useful for developer and investor site selection.
- Accounts for property taxes, insurance, and PMI in the calculation, capturing full housing cost burden.
How to use it / Key details
Released quarterly by NAHB; access via their website or Eye On Housing blog. The index assumes a 10% down payment (unlike NAR’s 20%) and uses HUD-reported median family income. Compare CHI across metros to identify which markets require the smallest income share for homeownership. Track the low-income CHI separately if your research focuses on entry-level buyer affordability or workforce housing needs.
3. Zillow Research (ZORI and ZHVI)
What it is
Zillow publishes two primary affordability indices: the Zillow Observed Rent Index (ZORI)—a monthly measure of asking rents controlled for quality changes—and the Zillow Home Value Index (ZHVI)—a measure of typical home values across regions. Zillow also calculates derived affordability metrics like “New Renter Income Needed” and “Affordable Home Price” to show what income is required to stay within a 30% cost-burden threshold.
Why it matters
- ZORI is a leading indicator for rental market trends and is widely used by investors to gauge demand.
- Granular geographic coverage: national, metro, county, city, and ZIP-code levels.
- Monthly updates and freely available data downloads make tracking current market conditions easy.
- Derived affordability metrics (income needed, affordable price) connect home/rent values directly to income requirements.
How to use it / Key details
Access all Zillow data free through research.zillow.com/data; data is updated monthly with a 2-week lag. ZORI measures asking rents on active listings (not executed rents), so it can overstate actual rent growth in tight markets where landlords renew existing tenants at smaller increases. Use ZORI for comparative analysis (which markets have momentum?) rather than absolute rent levels. Pair it with Census income data for quick affordability ratios.
4. American Community Survey (ACS)
What it is
The American Community Survey is the Census Bureau’s primary source of updated housing information between the decennial census. Released annually, the ACS captures home values, rents, housing costs, utilities, housing age, and occupancy data. It is available in 1-year and 5-year rolling averages; the 1-year covers only counties with 65,000+ population, while the 5-year covers all geographies.
Why it matters
- Most comprehensive official housing dataset; covers both owners and renters.
- Enables tracking of cost-burden rates (share of income spent on housing) by demographic group.
- Data are available down to Census tract level, supporting hyperlocal affordability analysis.
- Linked with HUD administrative data in special tabulations (CHAS) for targeted affordability research.
How to use it / Key details
Access ACS data through census.gov, American FactFinder, or via PUMS (Public Use Microdata Sample) if you need to create custom cross-tabulations. The survey asks households about selected monthly owner costs (mortgage, taxes, insurance, utilities, HOA) and gross rent, enabling direct cost-burden calculations. Use 5-year estimates for small areas; 1-year data is faster but geographically limited.
5. HUD’s Comprehensive Housing Affordability Strategy (CHAS) Data
What it is
CHAS data are custom tabulations of American Community Survey responses prepared annually by HUD. They are designed to show the extent of housing problems and needs, particularly for low-income households, by breaking down housing cost burden by income level, family type, and race/ethnicity. HUD uses CHAS to allocate federal funds and support local housing planning.
Why it matters
- Isolates affordability challenges for specific income tiers and demographic groups.
- Quantifies the number of households with cost burden (typically 30%+ threshold).
- Available down to local jurisdiction level, supporting comprehensive planning and grant applications.
- Designed for policy and program evaluation, making it highly relevant for affordable housing analysis.
How to use it / Key details
Access CHAS via HUD USER (huduser.gov) using their web-based query tool or by downloading raw data files. The tool provides counts of cost-burdened households, housing quality issues, and unaffordable rentals/sales by income. If you’re analyzing HUD grant applications, Consolidated Plans, or housing bond issuances, CHAS data is often required or expected to justify need.
6. American Housing Survey (AHS)
What it is
The American Housing Survey is a biennial Census Bureau survey sponsored by HUD. It covers roughly 100,000 housing units and collects detailed information on housing conditions, costs, demographics, vacancies, and physical characteristics. The survey has both national and metro-area versions, with the national version published every two years.
Why it matters
- Captures housing conditions beyond affordability: quality, age, vacancy, and maintenance issues.
- Provides demographic breakdowns by household type, allowing analysis of affordability by family structure.
- Long historical continuity (since 1973) enables multi-decade trend analysis.
- Metropolitan data allows regional comparisons of housing stock characteristics and costs.
How to use it / Key details
Download AHS data from census.gov/programs-surveys/ahs.html or HUD USER. The AHS Housing Affordability Data System (HADS) is a derived dataset specifically organized for affordability research. Note: AHS data are collected biennially (not annually), so updates lag behind Census’s annual ACS releases. Use AHS when you need housing-quality context alongside affordability metrics.
7. FRED (Federal Reserve Economic Data)
What it is
FRED is the Federal Reserve Bank of St. Louis’s open-access economic database that hosts thousands of time series, including NAR’s monthly Housing Affordability Index (both fixed and ARM versions), Freddie Mac mortgage rates, home prices, and other housing-related indicators. Data are updated automatically and made available in multiple download formats.
Why it matters
- Centralizes housing affordability data alongside broader economic indicators (unemployment, income, inflation).
- Allows easy visualization, download, and export of time series for economic modeling.
- Reliability and consistency: FRED is a trusted Fed resource, commonly cited in academic and policy research.
- Enables quick correlation analysis (e.g., affordability vs. mortgage rates vs. GDP).
How to use it / Key details
Visit fred.stlouisfed.org, search for housing indicators by series ID (e.g., FIXHAI for NAR fixed affordability), and download data in multiple formats (XLS, CSV, JSON). FRED’s graphing tool is useful for quick visual comparisons and trend identification. Note: housing affordability data available through FRED typically lag behind original source publications by a few weeks.
8. HUD’s Homebuyer Affordability Index
What it is
HUD’s Homebuyer Affordability Index is a ratio-based measure calculated by HUD’s Economics and Market Analysis Division (EMAD). It compares the median income in an area to the income needed to afford a median-priced home while spending no more than 30% of income on housing. An index of 1.0 or above indicates a typical family can afford the median home; below 1.0 indicates unaffordability.
Why it matters
- Direct comparison metric: makes it easy to see which areas are affordable vs. unaffordable at a glance.
- HUD also publishes a rental affordability index using the same methodology, enabling owner/renter comparison.
- Tied to HUD policy and funding allocations, making it relevant for compliance and planning.
- Consistent methodology across metros allows direct cross-market ranking.
How to use it / Key details
Access HUD homebuyer and renter affordability indices through huduser.gov/portal. EMAD updates these measures quarterly. The sales index covers all metros; the rental index is available for states and some metro areas. Use these indices when you need a simple pass/fail test of affordability or want to rank metros from most to least affordable.
9. Joint Center for Housing Studies (JCHS)
What it is
The Joint Center for Housing Studies at Harvard University publishes an annual “State of the Nation’s Housing” report with deep analysis of housing affordability, supply, demographics, and policy challenges. The reports synthesize data from Census, HUD, NAR, NAHB, and other official sources, plus original research, to provide context and interpretation.
Why it matters
- Provides narrative context and policy framing around the data—not just numbers, but explanation of trends.
- Combines multiple data sources in one report, reducing the need to manually reconcile different datasets.
- Identifies emerging affordability challenges before they become mainstream news.
- Free, publicly available; widely cited in housing policy discussions.
How to use it / Key details
Download annual reports from jchs.harvard.edu. JCHS reports include detailed data tables, methodology notes, and policy recommendations. Use JCHS reports for literature review, baseline statistics, and to understand which affordability trends deserve attention. The JCHS blog often highlights preliminary findings and provides updated analysis between annual report releases.
10. Ocity.org Housing Affordability Index
What it is
Ocity.org publishes an annual Housing Affordability Index ranking 500+ U.S. cities by affordability using price-to-income (PTI) ratios and rent-burden metrics. The data combine Census ACS income figures, Zillow home-value and rent data, and Bureau of Labor Statistics metrics. Cities are ranked by lowest PTI first, showing which markets offer the most purchasing power.
Why it matters
- Bridges rental and ownership affordability in a single, city-level comparison.
- Identifies regional patterns (e.g., Midwest cities maintain 2-3x PTI; coastal metros exceed 7-10x).
- Highlights the rent-burden gap: some cities have burden under 15%, others exceed 40%.
- Useful for relocation analysis, site selection for developers, and migration trend research.
How to use it / Key details
Access the Ocity.org Housing Affordability Index report at ocity.org/reports/housing-affordability-index-2026. The report includes detailed methodology, full city rankings, and regional insights. Use Ocity to answer “which cities are most affordable?” or to identify affordability arbitrage opportunities. Note: only cities with population over 50,000 are included, so smaller markets are not represented.
FAQ
What is the difference between asking rent and executed rent, and why does it matter?
Asking rent is the posted price for a new lease (tracked by Zillow’s ZORI), while executed rent is what tenants actually pay. In slow rental markets, landlords may renew existing tenants below the asking price, so ZORI can overstate actual rent growth. For affordability research, try to pair ZORI with Census ACS gross-rent data (executed rents) to avoid bias toward new-lease pricing.
Should I use NAR or NAHB affordability data?
Both are credible, but they measure slightly different things. NAR’s index uses a 20% down payment and is released monthly, making it responsive to short-term rate changes. NAHB’s Cost of Housing Index uses 10% down, includes taxes and insurance, and is released quarterly. Choose NAR for trend spotting; choose NAHB for policy discussions focused on cost burden or when you need metro-level existing-home data.
Can I compare affordability across states using ACS data?
Yes, the Census Bureau’s ACS 1-year estimates include state-level summaries of home values, rents, and cost burdens. However, cost-of-living adjustment varies by state, and ACS income is pre-tax, so direct state comparisons can be misleading. For fairer cross-state analysis, normalize by local income using price-to-income ratios or pair ACS with regional wage data from BLS.
How often are housing affordability datasets updated?
Update frequency varies: NAR publishes monthly, NAHB quarterly, ACS annually (1-year) or every 5 years (5-year rolling average), Zillow monthly, and JCHS annually. For real-time monitoring, rely on NAR and Zillow. For policy research and demographic analysis, ACS and CHAS are standard but arrive with a lag (often 9-12 months after data collection).
Which data source is best for analyzing rental affordability?
For current rental asking prices and trends, use Zillow’s ZORI or the affordability metrics they publish. For executed rents, Census cost-burden data, and demographic breakdowns of renters, use ACS or the HUD renter affordability index. If you need detailed rental market conditions including vacancies and turnover, turn to the American Housing Survey.
