The term "affordable housing" refers to housing that is considered economically accessible for individuals and families whose household income falls at or below the Area Median Income (AMI), as evaluated by either national or local government authorities through an officially recognized housing affordability index. However, in the United States, the term is mostly used to refer to housing units that are deed restricted (for typically at least 30 years) to households considered Low-Income (80% of AMI), Very Low-Income (50% of AMI), and Extremely Low-Income (30% of AMI). These units are often constructed by non-profit "affordable housing developers" who use a combination of private money and government subsidies. For-profit developers, when building market-rate developments, may include some "affordable" units (often 10-30%), if required as part of a city's inclusionary zoning mandate.
Housing has consistently been the largest expenditure within the average American family's financial plan. Housing expenses have also traditionally outpaced income growth, especially impacting those who rent their residences. Following the Great Recession in 2008, there has been a substantial decline in the rate of home ownership, leading to increases in foreclosures and short sales. This, in turn, has driven a surge in the number of individuals and families opting to rent homes, causing greater rental expenses.