Moved here, SW FL. in 1986 with 20' C having 2 roof vents left open 24/7 and never Mold or Mildew. After every use a quick clean of fridge, let dry out for 2 days, shut doors and never an issue.
1992 upped to 30' A with 3 vents open 24/7 no issues including fridge.
2010 upped to 36' A with 3 vents opened 24/7 still no issues including fridge.