My house in New Orleans, LA, was built in 1902(ish). It flooded during Hurricane Katrina in 2005. There are 2 apts in the basement; I am thinking about redoing at least one. There was central air and heat originally in each apt. Do I redo with existing ductwork (above the water line, but sat in an area that did have active mold at one point) or is it more cost efficient to go with the ductless mini systems? All units (compressors, etc.) would need to be replaced.