Just to be clear... I do not recommend a power vent plus the ridge vent. I favor the ridge vent w/o the power ventillator.
Although I am a strong proponent of using Ridge Vents, especially the styles that have the External Wind Deflecting Baffle incorporated into their design, why mess with a system that seems to be working adequately?My house has three gables - two of which have a 12"x8" vents - the third has a powered thermostatically controlled fan. Keeps my attic very cool... relative to the 3000 degree Florida sun. This will probably go away when I get a new roof and get a ridge vent.
Prior to this installation my attic timber would get so hot it would burn my hands and make it impossible to be in the attic... pheww