Affordable housing refers to housing that is priced below market. Both rental apartments and homeownership condos can be developed as affordable properties. Non-profit organizations such as the Coalition, some for-profit developers and public housing authorities develop and own affordable properties. Properties are typically financed using a variety of public and private funds from local, state and federal sources. Many of these sources of funds provide low interest, deferred interest or no-interest loans to properties so that they may be developed, and when the properties are sold or refinanced, those entities receive their funds back to invest in other properties. Affordable housing developers such as the Coalition are eligible to apply to use these funds, often combining them with conventional mortgages, to purchase, redevelop and maintain quality affordable housing.

The consequences of a lack of affordable housing are troubling. Young adults who grew up in a community often cannot afford to buy their first home or rent their first apartment in the same community they grew up in. Municipal employees cannot afford to live in the communities they serve. Businesses struggle with retaining and attracting employees when they cannot afford to live and work in the same community. In 2005, Massachusetts was the only state in the United States to lose population; many of those leaving the state cited the unaffordable cost of housing as a chief concern.