Affordable housing is general thought of as housing that is attainable to workers and families of median income. In Kentucky, there is generally an ample supply of affordable housing, as was pointed out by a 2009 University of Kentucky study  . The study examined the availability of owner-occupied and rental housing in Fayette County from 1998 to 2007 and defines affordable housing as homes for which families would not spend more than 30 percent of their annual income. The study stated that families making $47,000 dollars per year were able to afford about 1/2 of the houses in the city of Lexington.
If a housing supply is constricted while there is still great demand, prices of housing will inevitably rise.
Examples that will have some negative effect on the supply of affordable housing
The problem with having a city of increadibly affordable housing, is that property values won't rise; since if the values go up too much, they will not be affordable. However, if property values don't go up, then that will limit the options of homeowners if they want to sell their house to retire or borrow against their home's equity in order to start a small business.
Further more, when a government funded non-profit such as REACH or Habitat For Humanity does what is widely considered to be a good thing; help renovate or construct a home for an underprivileged family- they are in essence increasing the supply of available housing. This increase in supply will put some amount of downward pressure (possibly a very small amount) on prices in the area.
- Herald Leader article: accessed July 10, 2009