In the United States, efforts to improve the squalid living conditions of tenement dwellers led to projects like the now-landmarked apartment houses on Manhattan's Upper East Side built by the City and Suburban Homes Company at the turn of the last century (where this writer happily resided for several years in a rent-stabilized studio). Within the buildings, generous courtyards provide light and air in every room of the units, which average 370 square feet.

At about the same time, local authorities in cities throughout the country passed legislation requiring exposure to light and air in dwellings and setting a minimum size. But those very laws enacted at the turn of this century to protect the quality of housing—which include density and parking regulations—have until recently hampered developments of the existenzminimum of today, namely the micro unit. Targeted at young, college-educated individuals, the micro unit serves as a center-city option for those who prefer to have their own space rather than cramped quarters (often illegally altered) with roommates.