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Small is Beautiful: Micro-Units Can Help Make NYC Housing Affordable

Cities Housing

Editor's note: The following is the first chapter of the book Urban Policy Frontiers published by the Manhattan Institute.

The populations of many large cities across the U.S. are at an alltime high,[1] and there is a shortage of affordable housing as rent and property values increase faster than incomes.[2] The problem is particularly acute in New York. The National Low Income Housing Coalition (NLIHC) ranked the state as the country’s fourth-leastaffordable rental housing market,[3] and the Council for Community and Economic Research ranked New York City (with an estimated population of 8.5 million) as having the most expensive cost of living in the U.S.[4]

Measures need to be taken throughout the U.S. to increase the housing stock, ensure that housing is affordable, and increase the variety of housing options that are available to better accommodate shifting demographics. This paper argues that these goals can be
achieved in New York City by strategic changes to zoning, density, and building-code requirements to allow for smaller units, shared units, and other alternative housing arrangements.

The Mismatch Between Supply and Demand

There are approximately 3.13 million households in New York City.[5] According to research by the nonprofit Citizens Housing and Planning Council (CHPC), the makeup of these households varies widely (Figure 1).[6]

The physical characteristics of occupied housing in NYC reveal a discrepancy between the available housing stock and the city’s demographic profile (Figure 2).

For example, while 32% of households are single people and another 16% are couples without children who could comfortably rent or own studios or one-bedroom apartments—for a total of 48%—only 38% of occupied apartments are of this type. That’s a potential 10% deficit. But shared housing—unrelated and related adults (who are not couples) currently living together—represents a latent demand for single-person housing. If we assume that these individuals would prefer to live in their own units, the total deficit of small apartments (studios and one-bedrooms) could be as high as 35%.[7] Based on CHPC research, 87% of shared units show the presence of a single person who, in theory, needs a small space. Furthermore, there is very likely a gross undercount of shared units. A survey by two nonprofits several years ago estimated that there are 114,000 illegal units in New York City.[8]

The shortage of appropriately-size and affordably-priced housing is further illustrated by the percentage of NYC residents who can rent an apartment in a new development with middle or even low land costs. To estimate this, we came up with a rough but realistic calculation, based on rule-of-thumb pricing for construction costs, financing, and profit margins and compared it with income data from the U.S. Census Bureau’s American Community Survey (ACS).

First, we estimated the costs associated with building new housing units in NYC, including land, construction, labor, and financing. We then looked at data from the ACS to determine what percentage of households could afford a new unit based on a  determination by the U.S. Department of Housing and Urban Development (HUD) that affordable rent be no more than 30% of monthly adjusted income.[9] We further broke this down based on household income by household size to understand how household size affects affordability. For example, a five-person household cannot share a unit with fewer than three bedrooms without being considered overcrowded (the legal determination of overcrowding is examined in more detail below.)

According to our calculations (for more detail, see Figures 10 and 11), 25% of all NYC households can afford a new one-bedroom apartment, and 18% of renter households can meet such rent with 30% of their income. When rental households are broken down by size, these numbers vary significantly. About 16% of the city’s singleperson renter households can afford a newly built studio, while only 10% can afford a new one-bedroom unit. Similarly, 31% of two-person renter households can afford a studio, while 25% and 18% can afford one- and two-bedroom apartments, respectively. Affordability is an even greater problem for larger households. If a six-person renter household were to occupy a newly built three-bedroom apartment, only 6% of six-person renter households could afford to pay rent with 30% or less of their income.

Though our numbers are a rough estimate of new development costs, they suggest that less than one-fifth of single-person renter households (30% of all NYC households) are able to rent a new studio unit affordably. Second, 3+ bedroom apartments are  particularly unaffordable, with less than 9% of all renter households able to afford a newly built three-bedroom unit. Given that single-person households and couples without children account for 48% of all NYC households, why do 64% of the housing units have two or more bedrooms?

One factor may be the assumptions that informed planning policy in the past half-century. In 1950, 78% of households consisted of a married couple with children. Since then, there has been a steady decline in the nuclear-family household. By 1989, the percentage of this type of household dropped to 56%, and by 2013, to 46%.[10] Despite this decline, NYC density regulations and parking requirements encourage the construction of larger, family-size units.

Density factors in the NYC Zoning Resolution limit the number of units in a building, essentially establishing that the minimum average unit size be somewhere between a studio and one bedroom. For multifamily buildings, the density factor is 680 square feet (sf) per unit. Using a loss factor of 20%,[11] the minimum average net unit size of a finished apartment is approximately 544 sf, which is between a typical studio and one bedroom. A crucial point: the Zoning Resolution density regulations require a building’s average unit size to be 680 sf, over twice the size of a modern “micro-unit”—a residential unit of about 300 sf.[12] These regulations essentially prevent the construction of buildings of primarily small or micro-units, as larger units are required to offset the floor area of smaller units so that the average unit size in a building exceeds the minimum. Thus, new housing developments cannot legally provide a high concentration of small units.

Parking requirements also influence the type of units that are built—by creating an increased cost to developers providing smaller units. For new residential buildings in New York City, parking requirements are determined by the number of units in a building, as opposed to the number of bedrooms. This means that a building consisting of large units requires fewer parking spaces than a building of the same size that has been divided into small units, even though both buildings can house about the same number of people. This is especially significant, given that the cost to build off-street parking in NYC can cost upward of $50,000 per enclosed parking space.[13] In addition, the ability for a developer to recoup the capital used to build parking influences how much it is willing or able to provide. In affordable and low-cost housing, residents are less likely to own a car and less likely to pay for off-street or private parking facilities.[14]

It should be noted that the core of Manhattan (areas below 110th Street on the west side of Central Park and below 96th Street on the east side) imposes a parking maximum rather than a minimum, a restriction added in 1982 to reduce air pollution in the congested city center.[15] According to 2015 ACS data, Manhattan also has significantly higher concentrations of studios and one-bedroom apartments (Figure 3). The parking maximum, which effectively removed the parking “minimum,” is likely one of several factors contributing to this.

Los Angeles provides an example of how to modify parking requirements. The city’s zoning code adjusts parking requirements per bedroom, such that studios require one space, one-bedroom units require one-and-a-half spaces, and two-or-more-bedroom
units require two spaces.[16] Though the parking per unit required in Los Angeles exceeds what is required in NYC (because it is a more car-dependent city), a room-based parking requirement model could alleviate the small-unit parking penalty that is indirectly imposed by the NYC Zoning Resolution.

The Options

New York City, as well as other cities, has three ways to ameliorate a shortage of affordable housing:

  • The city could use “up-zoning” to enable greater residential density, such as by a higher floor area ratio (FAR).[17] New York is pursuing this avenue but with mixed results. Up-zoning often meets resistance because people do not want to see change in their neighborhood.
  • New units can be built on undeveloped land, even in cities limited by political and geographic boundaries. For example, NYC could allow building over railyards and highways, creating development potential over existing, often publicly owned, infrastructure. The authors’ architecture firm recently studied building over a railroad cut in the Bronx.[18] There is available land in the areas around New York, but transportation, politics, regulations, and other issues have limited density increases in the ring around the city.
  • Cities could find ways to house more people in the same space. This can be done by creating smaller, more efficient units, or having people share larger units. This strategy is the focus of this paper.

Small Living Units: Past Controversies and Present Considerations

Small, affordable units have long been part of the housing stock in high-density cities, but they can lead to unsafe, unhealthy, or dangerous living conditions. Tenement housing for poor workers and immigrants in NYC in the late 19th and early 20th centuries, for example, was often overcrowded and the living conditions unsafe. Single Room Occupancy (SRO) buildings and hotels provided low-cost rooms with shared bathrooms and kitchens through much of the 20th century but were marred by bad management practices and poorly maintained facilities.

Despite SROs’ unsavory reputation, Brian Sullivan and Jonathan Burke have shown that they served a crucial role as an affordable housing option; in fact, they represented more than 10% of NYC’s housing stock in the 1950s.[19] The prevalence of SROs as a low-cost housing option “intensified connections between ‘SRO housing,’ ‘bad housing,’ and the poor.”[20] Racial undertones also surrounded the discussion and eventual demolition of SROs because, particularly after World War II, there was an influx of minorities into SRO housing.[21]

Beginning in the 1960s, NYC created tax and financial incentives that encouraged landlords to convert SRO buildings into apartments. By the late 1980s, more than 100,000 low-cost SRO units had been removed from the market. The loss of this housing contributed to the increasing homelessness crisis, and, in 1985, the government attempted to reverse its policy, first by removing the incentives for conversion, and then by placing a temporary ban on the conversion of SROs.[22] Currently, NYC’s SRO policies are contradictory—they do not allow the construction of new for-profit SRO buildings but strongly discourage the conversion of existing SROs. In addition, nonprofit developers for the past 25 years have been allowed to build new SRO and mini dwelling units with city and state support if they provide supportive services.[23] SRO housing units in the “bad old days” were substandard not necessarily because of the amount of space but because of the quality of the buildings, shared living facilities, and maintenance. A successful SRO housing policy would hinge on management practices. So-called supportive SRO housing achieves this by requiring newly constructed SRO housing to include social services for residents—which inherently require more management by specialized staff. Supportive housing, moreover, is run by nonprofit institutions that specialize in helping those in precarious situations. If well-maintained SRO units are, in fact, livable, for-profit SRO units with adequate management might be reintroduced as an affordable housing option.[24]

Affordability Considerations

With housing construction costs growing at a faster rate than both housing costs and incomes, the nation’s housing affordability gap continues to increase. SROs are just one example that can help address this.[25] Micro-units have the potential to alleviate this problem, primarily because they cost less to build per unit, allowing developers to charge a lower rent per unit while still maintaining a profit in private developments. Meanwhile, current demographic trends suggest that the size of families will continue to decline, as will the corresponding demand for large apartments. A study by CBRE Global Investors, a real-estate investment company, predicted that by 2025, only 10% of new households in the U.S. will have children and only 25% of all households will have children.[26] If this prediction is accurate, the current mismatch between housing stock and demand could worsen unless many more small units are built.

It should be noted that newly constructed micro-housing may not directly address affordability. In NYC, for example, many micro-units are marketed to young professionals with high-end convertible furniture, generous amenities, and prime locations. Studio apartments (ranging from 265 sf to 360 sf) at Carmel Place, a new micro-unit project by nArchitects, offer 22 units that are affordable, but the remaining market-rate units start at about $3,000 a month. This implies an annual income of about $120,000 if the rent is to represent 30% of the renter’s income.[27] Even so, market-rate micro-units could relieve upward pressure on rents by increasing the overall housing supply and by providing young singles with a housing option that reduces the burden on other housing stock.


Smaller apartments do raise the risk of overcrowding—which has been associated with psychological stress, especially in children—in numerous studies.[28]

HUD defines overcrowding as any dwelling unit that has more than two people per bedroom.[29] By this standard, NYC has a real problem. In a 2015 report, city comptroller Scott Stringer noted: New York City’s overall crowding rate, which includes rental and ownership housing units, rose to 8.8% in 2013, compared to 7.6% in 2005—a proportional increase of 15.8%. The City’s crowding rate is more than two and a half times the national crowding rate of 3.3%.[30] One hopes that the creation of more units would reduce overcrowding, but modified density requirements should be coupled with increased enforcement of regulations to prevent the unhealthy effects associated with overcrowding.

Accessibility Requirements

For most housing, a building must comply with the Federal Fair Housing Act and the New York City Building Code. With the 2014 update of the New York City Building Code, the two standards are largely in alignment. Accessibility codes affect minimum unit sizes because they require minimum door and hall sizes, as well as clearances at doors, appliances, and fixtures that allow mobility-impaired individuals to comfortably and safely navigate a space. Figure 4 shows a bathroom and kitchen layout for a 270-sf micro-unit that approaches the minimum possible size while complying with accessibility codes, which we see as a given condition. In addition to the standard bathrooms, our firm developed a slightly smaller bathroom that merges the shower and the toilet spaces (Figure 5). This unit shows that careful design would allow living units considerably below the city zoning’s current 680-sf average per unit, while meeting accessibility requirements.

Small Unit Design and Management

The design in Figure 4 is one of many that are possible. Another apartment design has been developed by Graham Hill, founder of LifeEdited. This unit is located in lower Manhattan in a typical apartment building (Figure 6). The space is designed to comfortably house two people, accommodate a dinner party of up to 12 people, and could even sleep two additional guests within 420 square feet.[31

The recent “adAPT NYC” competition hosted by the New York City Department of Housing Preservation and Development (HPD) allowed the city to create a special zoning exception to allow for experimental micro-housing units, which resulted in Carmel Place, a project mentioned earlier. Carmel Place features 260-sf to 360-sf studio units with convertible furniture and community spaces (Figure 7).[32] Recent college graduates, who are accustomed to small and shared spaces, could adapt to such a micro-unit more readily. People who spend part of their week in another city, or who spend weekends elsewhere, may greatly prefer the affordability of a micro-unit to a hotel. At an institutional level, supportive housing in New York has successfully provided small units of just over 300 sf for singles populations, typically with special needs and supportive services. As with supportive housing, we believe that with small units, the amenities outside the unit become more important to the success of the building and the unit.

Legal Perspective

Three regulations define the minimum room size in NYC:[33] the New York City Housing Maintenance Code, the New York City Building Code, and the New York State Multiple Dwelling Law. Their main requirements are that every apartment has a living room of 150 sf[34] and a minimum of 80 sf per person in the case of multiple occupants[35] and that each room conforms to certain minimum required dimensions. Within these constraints—and including the addition of cooking, bathing, and circulation spaces—design studies by the authors’ architectural firm indicate that the minimum unit size under current law is approximately 270 sf.

Figure 12 (see in PDF) in the Appendix summarizes our findings for minimum unit sizes in many other cities.[36] Overall, the habitable area requirement of a minimum of 150 sf per apartment in New York City does not seem to be out of line with other U.S. cities. However, the parking and density regulations in the NYC Zoning Resolution, discussed earlier, prevent the construction of entire buildings to this density.

If these requirements are intended to prevent the development of uninhabitable apartments by establishing minimum unit sizes, the requirements are redundant and are already established by the habitable area requirement. If the density requirements are intended to prevent increased population density, the requirements are likely outdated; in many cases, population density would not change drastically if the limits were removed, given the area per person requirements and how units are shared and occupied. The density requirement duplicates the requirements of the state’s Multiple Dwelling Law, the NYC Building Code, and the city’s Housing Maintenance Code. Updating the Zoning Resolution’s density requirement would allow for the construction of new buildings with a higher proportion of small units.

HPD also has design standards for apartments that establish the minimum unit size, room size, and room dimensions. Until recently, a studio had to be slightly over 400 sf to meet the standards. In 2016, the standards were modified such that a unit could be designed in 350 sf. HPD’s standard for supportive housing allows for units of about 310 sf, or what we would call a mini-dwelling unit. As previously noted, these design standards also require that 10%– 15% of the building be community and/or social-services spaces.[37] In the Zoning Resolution, buildings that provide housing and social services are considered nonprofit entities with sleeping accommodations, which allows the city to waive the density requirements and/or lower the parking requirement.

How Small Should We Go?

CHPC has organized two studies—One Size Fits Some and Making Room—and one exhibition on small units in developed countries. In addition to looking at the U.S., small-housing-unit projects in Germany, Spain, and Japan were studied. Azby Brown, an architect in Tokyo, analyzed Japanese living spaces from 150 years ago, explaining that three-fourths of the urban population in Japan lived in 105- sf living spaces that utilized shared cooking and hygiene facilities,[38] much like current SRO units. Architect Vicente Guallarte presented projects from Valencia, Spain, including one that incorporated generous shared spaces to give a 270-sf unit an effective living space of 807 sf.[39]

The studies make clear that sharing spaces and resources is an essential part of living in small spaces. The smaller the space one lives in, the more options one needs outside this space, such as a shared lounge, balcony, exercise room, or community room. These amenities allow people to successfully live in less space because it provides options to spend time in larger spaces that are still semiprivate and familiar.

Another option that could facilitate smaller living units is to accompany small units with shared household accessories, as was proposed by Graham Hill for the NYC adAPT competition team in collaboration with Curtis + Ginsberg Architects, Jonathan Rose Companies, and Grimshaw.[40] For items that people use infrequently but that require large amounts of space to store (such as extra chairs, tables, large pots for cooking big meals, and tools), a communal storage space filled with shared items could reduce the need for individual storage closets. Current trends for digital storage and devices could also reduce spatial needs for apartments. Forty years ago, listening to music required vinyl records and a turntable, which took up space. Now one’s entire recorded music library can be saved on a storage device the size of a key; TVs used to be very large but now are flat and take up about the same space as a large painting on a wall. Instead of keeping paper documents, one can file them electronically, eliminating the need for file cabinets. In short, technology allows us to reduce the amount of storage space we need.

Another consideration: designers tend to think about living spaces in two dimensions: living spaces, furniture, and rooms are drawn in plan and the space above and below them are assumed to be devoted to that use. As a result, space below or above a couch, for example, might not be utilized to its full potential. However, if we look at how living spaces, storage spaces, or equipment can be stacked vertically, our understanding of how living spaces can be arranged changes. Architect Peter Gluck designed micro-loft studio units with tall ceilings and mezzanines (kitchenettes and bathrooms on the ground level in the space below the mezzanines) and shared communal spaces (Figure 8).

Given these considerations, we believe that it is possible to design a much smaller apartment than is currently allowed by density requirements or financially reasonable, given parking constraints— but one that still meets current building code requirements. In New York City, at least one habitable room of 150 sf is required, excluding the bathroom and kitchen areas. However, to meet the additional requirement of 80 sf per person, living rooms should be designed to be 160 sf, so that two people have the option to share the unit legally. As noted, the smallest code-compliant apartment permitted in New York City is about 270 sf. We think that this is about the minimum size that should be permissible for reasonable habitation for a full apartment. In the case of SROs, units could be as small as 150 sf, since bathrooms and kitchens are shared.[41]

Next Steps

NYC’s parking requirement discourages smaller units by making them costlier. Yet there are a few possible fixes. One already being implemented is the “Transit Zone” exclusion, which allows affordable housing developments to waive parking requirements if they are built near mass transit.[42] Another approach is not to require parking but to allow it if potential renters desire or demand it. For many developments, especially in lower-density areas and areas not well served by mass transit, the developer tends to build more than the required parking, since people will not purchase or rent without a parking space. A more politically palatable solution would be for parking to be calculated by the number of bedrooms, as is done in Los Angeles, which would make developments with small units more feasible to build.

There is a certain point beyond which a lower unit size does not significantly reduce cost. Bathrooms and kitchens are the most expensive rooms to build in a new apartment, so there is a base price associated with an apartment of any size. While this price floor is dependent on a range of factors, our cost estimates suggest that a studio in a new development built to today’s size requirements can be afforded only by a person earning at 140% of Area Median Income (AMI).[43] One benefit of micro-units is that more units can be built on a piece of land, lowering the per-unit land cost. Encouraging the production of micro-units may not immediately or directly provide affordable housing. However, micro-units may free up older, more affordable units or become more affordable as micro-unit buildings age and become more widespread.

Additional Solutions

Apart from small units, there are two related ways of increasing the number of apartments without building more or larger buildings: shared units and basement units.

Shared units have become ubiquitous in New York City. Typically, younger singles or low-income singles will rent or purchase an apartment together, allowing them to find a relatively affordable housing option by taking an apartment designed for a family and sharing it. Shared units also enable a higher density because one unit of 600 sf is occupied by two individuals, resulting in an effective 300-sf unit per person. Our firm has produced studies for apartments that take advantage of this by developing a shared two-bedroom micro-unit that allows for some privacy between two unrelated tenants that share common spaces (Figure 9).

By law, shared units are limited to three unrelated people living together.[44] This limitation is rarely enforced and, according to a court ruling in California, may even be illegal.[45] Regulations covering minimum area per person and room size seem to cover basic density requirements. Allowing more than three unrelated people to live together in a shared situation should be permitted, but it also needs to be controlled and inspected more consistently by the regulatory agency to ensure that no unsafe conditions are created, such as overcrowded units or room subdivisions that block fire escapes. Legalizing basement apartments[46] could also increase urban housing options. Early this year, CHPC released a study on the conversion of single-family houses into two-family residences in NYC.[47] The study was based on homes that are not affected by the Multiple Dwelling Law, which applies to all buildings with three or more units. It also was limited to locations where the additional apartment does not require an additional parking space or where it was expected that there was an additional parking space available, because of the parking requirement discussed earlier.

Within these limits, the study showed that there were 12,000– 38,000 units that could be created or legalized. If cellars with adequate light and ventilation for living spaces were included, up to 210,000 units could be converted into legal units. If two-unit buildings were permitted to convert to three units with some relief from the Multiple Dwelling Law, more units would be available. Following the suggestions of the study would not lead to a direct increase in housing units in NYC, as many of the houses included in the survey have already been illegally converted into dwelling units. In these instances, the focus should be legalizing units, since this is important for safety and for homeowners to obtain financing for the conversion, which can occur only with a legal unit.

Legalizing basement units would also permit the creation of accessory units, sometimes called “granny flats.” These are apartments within a house that allow families to support aging members while maintaining a degree of privacy and separation. Finally, simplified regulations that allow for basement units would enable homeowners to benefit from a legal rental income.


Given the mismatch between NYC’s household types and housing supply, regulations should be modified to allow greater flexibility in housing options. Modifications would legalize currently illegal housing that meets building codes and the Zoning Resolution—such as basement apartments, subdivided apartments, and apartments shared by more than three unrelated people—but that does not satisfy zoning requirements.

Legalization would likely make life safer for occupants and first responders. Currently, public officials often look the other way on illegal housing, since vacating it would force many residents into the shelter system. It would be far better to bring this housing out of the shadows. There is also a need for more research establishing acceptable minimums without adversely affecting physical and mental health.

In New York City, we recommend the following:

  • The maximum number of people sharing an apartment should be removed (or increased) from the Zoning Resolution, the NYC Building Code, the (state) Multiple Dwelling Law, and the Housing Maintenance Code. The new rule should reside in one place.
  • Density requirements in the Zoning Resolution should be removed or reduced, so that units that meet building codes and provide healthy living environments are not prohibited.
  • Parking requirements should be modified so as not to penalize small units; for example, parking requirements could be based on the number of bedrooms.
  • New for-profit SRO buildings with clear and enforceable requirements for maintenance and common facilities should be permitted and encouraged.

Regulations that do not need adjustment include:

  • One room in each apartment shall be 150 habitable sf
  • 80 habitable sf per person shall be provided in an apartment
  • Minimum room dimensions
  • Accessibility codes

Ultimately, these recommendations aim to increase the diversity of housing options available in NYC and to facilitate the construction of units that are sized according to the needs of the city’s shifting demographics. In NYC and other large cities, this means increasing the amount of studio and one-bedroom units for the increasing population of singles and childless couples.

We understand that the politics of implementing density changes and parking requirements is difficult, particularly when people believe that the quality of their neighborhoods or lives will deteriorate. Still, our recommendations are not intended to radically change density and parking amenities. Rather, they aim to make the current effective density of the city legal and to remove barriers that prevent the construction of housing that more closely resembles the demographic profile of NYC’s population.

We thank David Dixon, Sarah Watson, and Frank Braconi for offering their expertise to this paper; and Graham Hill for providing images of his work. We also thank the NYU Furman Center for its assistance with data and comments. Finally, we thank the Citizens Housing and Planning Council, whose Making Room initiative serves as the basis for much of this paper.


We estimated the average cost per square foot of new construction in the NYC area to be $300, based on Mark Ginsberg’s experience in managing an architecture firm. In addition to this hard cost, we assumed 28% soft costs (architects’ and legal fees, project management, etc.). We factored in monthly operating costs based on the New York City Rent Guidelines Board 2016 Income and Expense study[48] and estimated financing for a 30-year amortizing mortgage at 5.2% interest. We assumed a 10% cash-on-cash profit for the developer. We applied the per-sf costs over standard sizes for zero-, one-, two-, and three-bedroom apartments to estimate what a range of newly constructed units cost (Figure 10, see in PDF).[49] Next, we looked at the rentals necessary to compensate the developer for his costs and earn a competitive return on his capital. We calculated the income necessary to pay these rents (with housing costs pegged to 30% of income) and displayed the number and percentage of NYC households that could afford these units. For example, the household income necessary to afford a new studio unit is $87,659. There are 512,815 such rental households in NYC, 24% of the total, that meet this income threshold.


  1. Paul Mackun and Steven Wilson, “Population Distribution and Change: 2000 to 2010,” U.S. Census Bureau, Mar. 2011.
  2. RealtyTrac, Home Prices and Sales; RealtyTrac, 2006 Rental Affordability Report.
  3. Diane Yentel et al., “Out of Reach: No Refuge for Low Income Renters,” National Low Income Housing Coalition, 2016.
  4. For the city’s population, see NYC Dept. of City Planning, Current and Projected Populations, 2016. For affordability, see “COLI [Cost of Living Index] Release Highlights, Quarter 3, 2016.”
  5. U.S. Census Bureau, American FactFinder.
  6. U.S. Census Bureau, American Community Survey, S1101: Households and Families.
  7. This assumption does not account for people who deliberately choose to live in shared housing. It also does not include people living in illegally shared housing, which could significantly increase the deficit between housing supply and demand for smaller units.
  8. Chayya Community Development Corporation and Pratt Center for Community Development, “New York’s Housing Underground: A Refuge and Resource,” Mar. 2008.
  9. U.S. Dept. of Housing and Urban Development (HUD), HUD’s Public Housing Program.
  10. U.S. Census Bureau, “Families and Households”; Gretchen Livingston, “Fewer than Half of U.S. Kids Today Live in a ‘Traditional’ Family,” Pew Research Center, Dec. 2014.
  11. The term “loss factor” describes the proportion of area in an apartment that is unusable, such as the space between walls, structure, vertical shafts for ventilation, stairs, corridors, and space for plumbing and heating equipment.
  12. Micro-units achieve this result by taking advantage of efficient design and furniture. For density regulations, see NYC City Planning Commission, Zoning Resolution, Pub. L. No. Section 23-22, 2016.
  13. Angie Schmitt, “Americans Can’t Afford the High Cost of Parking Requirements,” Streetsblog USA, June 6, 2016. There is no parking requirement in Manhattan (largely south of 96th Street) and in a small area of Long Island City. Data show that there are many more small apartments in these areas—even though at these locations, parking spaces can typically pay for themselves.
  14. NYC Dept. of City Planning, “Inner Ring: Residential Parking Study,” Dec. 2013.
  15. NYC Dept. of City Planning, “Manhattan Core Public Parking Study,” Dec. 2011.
  16. Los Angeles Dept. of Building and Safety, Zoning Code: Manual and Commentary, sec. 12.21A.4.(C); City of Los Angeles, Summary of Parking Regulations.
  17. FAR is the ratio of lot area to the floor area of all the floors of a building. The higher the FAR, the larger the building can be on a given piece of land.
  18. Aaron Elstein et al., “New York Firms Envision Ways for the City to Absorb 9 Million Residents,” Crain’s New York Business, Oct. 30, 2016.
  19. Brian J. Sullivan and Jonathan Burke, “Single-Room Occupancy Housing in New York City: The Origins and Dimensions of a Crisis,” City University of New York Law Review 17, no. 901 (Winter 2014): 900–932.
  20. Ibid.
  21. Kenneth L. Kusmer, Down and Out, on the Road: The Homeless in American History (New York: Oxford University Press, 2002).
  22. Sullivan and Burke, “Single-Room Occupancy Housing,” argue that this action was “too little, too late.”
  23. Supportive services include access to social workers, health-care services, and social-support networks.
  24. See Josh Leopold, “Innovations NYC Health and Human Services Policy: Street Homelessness and Supportive Housing,” Urban Institute, Mar. 17, 2014; Lukas Vrbka, “Success and Struggles Point to a Better Way to Help NYC’s Chronically Homeless,”, Aug. 23, 2016.
  25. Andrew Aurand et al., “The Gap: A Shortage of Affordable Homes,” National Low Income Housing Coalition, Mar. 2017; Yentel, “Out of Reach”; Wendell Cox and Hugh Pavletich, “13th Annual Demographia International Housing Affordability Survey: 2017,”
  26. Anthony Wirth, “U.S. Urbanization Trends: Investment Implications for Commercial Real Estate,” CBRE Global Investors, 2016.
  27. Ondel Hylton, Micro-Apartments at Carmel Place Starting from $2,570 and Offering a Month Free,, June 9, 2016; Christine Brun, “Micro Housing Provides a New Option for Millennials and Seniors,” Daily Herald, Apr. 23, 2017.
  28. Gary W. Evans, Nancy M. Wells, and Annie Moch, “Housing and Mental Health: A Review of the Evidence and a Methodological and Conceptual Critique,” Journal of Social Issues 59, no. 3 (July 2003): 475–500; Scott M. Stringer, “NYC Housing Brief: Hidden Households,” Office of New York City Comptroller, Oct. 2015.
  29. HUD, Measuring Overcrowding in Housing, Sept. 2007.
  30. Stringer, “NYC Housing Brief: Hidden Households.”
  31. Graham Hill, “Life Edited,” As built, the apartment is not compliant with the accessibility requirements of the Americans with Disabilities Act.
  32. NYC Dept. of Housing Preservation and Development (HPD), adAPT NYC Request for Proposals.
  33. There are some exceptions, such as senior housing, which requires a minimum unit size of 325 sf, per the Zoning Resolution.
  34. NYC HPD, Housing Maintenance Code, “Minimum Room Sizes.”
  35. NYC HPD, Housing Maintenance Code, “Maximum Permitted Occupancy.”
  36. There is variation on minimum permitted sizes from city to city, and some of the information is difficult to compare because of differing methods to establish minimums. Some cities, including New York, have different requirements for SROs, compared with apartments. Others establish limits only on habitable space, while others require minimum room widths, which may further increase floor areas because of how rooms can be arranged.
  37. NYC HPD, Design Guidelines for Supportive Housing, 2015.
  38. Jerilyn Perine and Sarah Watson, eds., Making Room, “One Size Fits Some” (New York: Citizens Housing & Planning Council, 2009).
  39. Ibid.
  40. Hill, “Life Edited.”
  41. NYC HPD, Housing Maintenance Code.
  42. NYC Dept. of City Planning, Zoning Resolution, Appendix I: Transit Zone.
  43. NYC HPD, “What Is Affordable Housing?”
  44. See NYC’s Housing Maintenance Code and Building Code. There are fewer restrictive requirements in the state’s Multiple Dwelling Law and the city’s Zoning Resolution. Having different requirements in different codes is confusing and makes modification difficult.
  45. In City of Santa Barbara v. Adamson (1980), the California Supreme court struck down Santa Barbara’s definition of “family” in the zoning code as violating the right of privacy expressly guaranteed by the California state constitution.
  46. A below-grade room is considered a basement as long as 50% of the wall height is above-grade; otherwise, it is considered a cellar and is not legal for occupation.
  47. Kate Leitch and Sarah Watson, “Hidden Housing: The Case for a Conversion Program for Basement Apartments in NYC,” CHPC, Feb. 14, 2017.
  48. NYC Rent Guidelines Board, 2016 Income and Expense Study, Apr. 7, 2016.
  49. The authors note that this is by no means a universally applicable calculation; rather, it is an illustrative estimate.