1. Source control beats all. In a warm, humid climate, the biggest benefits come from investments in curbing air and moisture infiltration, blocking solar and external heat gain, reducing internal heat and moisture production and controlling indoor sources of air pollutants. If you control sources, there is far less need (and cost) to remove heat, moisture and indoor pollutants mechanically.
2. Random “natural ventilation” (through a leaky structure) does more harm than good. Controlled, filtered ventilation is better to always have enough but not too much fresh air for good air quality and energy efficiency.
3. The amount of air going out is balanced by the amount of air coming in. In a warm climate, avoid negative pressure; a slight positive pressure is preferable to a negative pressure.
4. Moisture flow is from warm to cold and also from more to less. Therefore, southern houses dry mostly to the inside; interior surfaces should be water vapor permeable (no vapor barrier on the inside).
5. Rain must be drained on a drainage plane. The region’s frequent rain and high humidity call for planned and built-in high capacity drainage and drying systems for all parts of the structure (walls, roof and foundation).
6. Preventing damage costs much less than repairing it. Insurance does not pay for everything, especially your time and trouble.