It should be mounted at least fifteen feet up in a large tree. I strongly suggest you place it seventy-five feet or more from any area where there will be significant human activity. The denser the canopy around the box, the better your chance of attracting a barred owl. Heat buildup in boxes exposed to direct sun is a major threat to owls in the South. Try to find a spot that will protect them from direct sun and consider adding vents to the top of the back panel.
Raccoons are also a major threat to barred owl eggs and very young owlets.
Raccoons look for food where they smell the scent of humans. Your success will depend on nest placement and on the availability of homeless owls in your neighborhood. You can, however, be sure that the owls in your area will find it very quickly. Whether they move in next spring is another question.