I am getting ready to reroof my home. I have researched attic ventilation on the internet and I am totally confused about ventilation requirements. My home is a single story ranch with 2076 sq. feet of heated area and a two-car garage (529 sq. ft). It has 14-soffit vents (7X14 inches each), four gable vents (18X22 inches each), and three roof power vents. My contractor suggested that I cover the power vent openings in the roof and install a ridge vent. Would this be a better method for attic ventilation than the power vents? Also, would the gable vents have an adverse effect on the ridge vent cooling? Any suggestions would be greatly appreciated. Thank you.