[billygoat22]

Humidity from outside is condensing on the cooler inside surfaces. Need to seal crawlspace walls and good vaporbarrier on ground, then the dehumidifier will dry things out.

My ducts aren't even insulated and they're not sweating with this setup.

 

[billygoat22]

Vents are required by boca code if I recall correctly, BUT, that don't make them right, especially when you consider some codes are generic and are used across the country without consideration to local environment.

In the North, vents will work well and you NEED them for attics in some types construction. In that part of country with cold climate, the vapor barrier is on the inside of house, but in hot humid climate like Georga, the vapor barrier should be on outside of wall.