Georgia isn't different than Dallas...possibly slightly more humid but not much thanks to all the man-made lakes around here. Any fan that moves a great deal of air is going to be pretty loud by sheer definition (unless you spend a lot of $$$ on one of those crazy large ceiling fans the dealerships use in their shops). But it seems to me one good scheme might be to suck the hot air out from the top. Our garage is connected to our house. What I've thought about is installing an HVAC fan in the attic and attaching it to a simple duct system that would suck hot air from the ceiling of the garage and push it into the attic (where it would go up and out the turbine vents on the roof).
