Quote Originally Posted by rnevil View Post
I live in Lousiana and during the summer my AC runs constantly on hot days. This year I had the AC system checked and all checked OK except for the fact that my attic is very hot (over 130) even though I have ridge vents and soffit vents. I think that my soffits vents area is sufficient but suspect that the ridge vent area is lacking because my home has four hip roofs(short ridges). I was considering installing a power vent (recomended by one AC contractor)but after reading here I have the feeling that installing wind turbines may be a better option. I have seen some homes in my area with a combination of ridge vents and wind turbines. I am also not sure how many turbines I should install. Can there be to many? Any thoughts and help would be appreciated?
In all honesty, I think best bang for the buck is THICK insulation on the attic floor, and AIRTIGHT ductwork if it is in the attic. Bottom line. Unless you insulate the roof deck, or unless you employ a radiant barrier with a 99.xx% radiant heat reflectivity, a ventilated attic will not stay near ambient temperatures, which is the ideal goal of any attic ventilation scheme.

For much residential construction, the largest contributors to heat gain into the structure (which determines the quantity and capacity of cooling needed to keep the interior comfortable) are windows and infiltration (leakage). A nominally insulated attic floor will keep heat gain from the attic to the interior below the percentages gained through single pane windows (particularly unshaded windows) and infiltration, Airtight, well-insulated ducts that run through the attic will assure the a/c system delivers more of its actual cooling output to the rooms vs. being lost to the attic via air leaks and heat gain into the ducts from the hot attic air and surfaces.