The Untapped Housing Supply: Could Roommates Help Solve America’s Housing Crisis?
America faces a severe housing affordability crisis. The standard response is simple: build more housing. New housing is essential. However, another question deserves attention.
Are we fully using the housing we already have?
This question is rarely discussed. Yet it may represent one of the largest untapped opportunities to improve housing affordability.
A Different Way to Think About Housing
Housing shortages are usually measured by counting homes. However, housing demand is driven by households, not people.
When two people share one home, they form one household. When they live separately, they form two households.
As a result, changes in household formation can significantly affect housing demand without adding or removing a single resident.
Over the past several decades, Americans have increasingly chosen to live alone. This trend has many positive explanations. People marry later. Americans live longer. Divorce rates changed family structures. Greater financial independence also allows more people to maintain their own homes.
Nevertheless, every one-person household requires its own housing unit.
Consequently, even modest changes in household size create large changes in housing demand.
The Housing Stock May Have More Capacity Than We Think
According to the U.S. Census Bureau, the average household size has steadily declined over time. At the same time, the nation’s housing stock has continued to grow.
Even so, housing affordability continues to worsen.
The conversation usually focuses on building enough new homes. That remains critical. However, existing homes may also contain unused capacity.
Many apartments and houses have spare bedrooms. Others are occupied by a single resident who pays the entire rent alone.
That raises an important question.
How many cost-burdened renters live alone today?
Unfortunately, the Census Bureau does not publish that figure in a standard table. Researchers must calculate it using the American Community Survey Public Use Microdata Sample (PUMS).
Based on current ACS data and published national housing statistics, a reasonable estimate is that approximately 10 million renter households both:
- consist of one person, and
- spend more than 30 percent of household income on housing.
The exact figure requires a custom analysis of the latest ACS microdata.
Why This Matters
Living alone does not mean someone should have a roommate.
Many people value privacy. Others have disabilities, caregiving responsibilities, or personal circumstances that make shared housing impractical.
However, many others could benefit from sharing housing.
Young professionals often seek roommates to reduce expenses. Likewise, older adults increasingly participate in home-sharing programs for affordability, companionship, and safety.
Therefore, the question is not whether everyone should share housing.
Instead, the question is whether more people could choose to share housing if better options existed.
A Small Change Could Have a Large Impact
The math becomes surprisingly powerful.
Suppose two million renters currently living alone chose to share homes.
Those two million households would become one million shared households.
As a result, roughly one million housing units would become available for others.
Importantly, no new construction would be required.
This thought experiment does not suggest that one million new homes become unnecessary forever. Instead, it demonstrates how household formation directly affects housing demand.
Even a modest increase in average household size could create meaningful housing capacity nationwide.
Shared Housing Is Not a Replacement for New Construction
Some readers may assume this argument opposes new housing development.
It does not.
America still needs millions of additional homes. Population growth, migration, aging infrastructure, and regional job growth continue to drive demand.
Furthermore, many communities already face genuine shortages of housing across nearly every price point.
Instead, shared housing should be viewed as another tool.
Communities need more housing supply. They also need policies that encourage better use of existing housing.
These goals complement each other.
Policy Opportunities Worth Exploring
Several strategies deserve greater attention.
Communities could modernize zoning rules that unnecessarily restrict unrelated adults from sharing homes.
Cities could encourage professionally managed co-living developments.
Communities could expand senior home-sharing programs.
Developers could also design apartments that better accommodate unrelated adults while preserving privacy.
Likewise, affordable housing developers and managers could evaluate floor plans that support flexible household arrangements over time.
These ideas will not solve every housing challenge. However, they could reduce pressure while new housing is planned, financed, and built.
The Data Gap
One surprising fact emerged while researching this topic.
The federal government publishes detailed affordability statistics. Yet it does not publish the national count of cost-burdened renters who live alone.
That statistic must be calculated from household-level ACS microdata.
Given today’s affordability challenges, this metric deserves much greater attention.
It would help policymakers better understand how much housing demand stems from limited housing supply versus changing household formation.
Looking Ahead
Housing affordability deserves more than one solution.
We should continue building more homes, streamline approvals, encourage innovation in construction, and expand modular and off-site housing. But we should also examine how existing homes are being used.
America’s housing crisis is fundamentally about matching people with housing.
Sometimes the answer is building more homes.
Sometimes the answer is building different homes.
And sometimes the answer is helping more people successfully share the homes we already have.
The most effective housing strategy will likely include all three.
References
- U.S. Census Bureau. 2024 American Community Survey (ACS) 1-Year Public Use Microdata Sample (PUMS). https://www.census.gov/programs-surveys/acs/microdata.html
- U.S. Census Bureau. American Community Survey 1-Year Estimates. https://www.census.gov/programs-surveys/acs
- Harvard Joint Center for Housing Studies. Housing Unaffordability Soared to New Highs in 2024. https://www.jchs.harvard.edu/blog/housing-unaffordability-soared-new-highs-2024
- Harvard Joint Center for Housing Studies. Are More Older Adults Sharing Housing? https://www.jchs.harvard.edu/blog/are-more-older-adults-sharing-housing
- U.S. Department of Housing and Urban Development. Comprehensive Housing Affordability Strategy (CHAS): Cost Burden Definitions. https://www.huduser.gov/portal/datasets/cp.html
- U.S. Department of Housing and Urban Development. Insights into Shared Housing. https://www.huduser.gov/portal/sites/default/files/pdf/Insights-of-Housing.pdf
