I have a gable roof on my house approx. 2500 sqft. I have soffit vents in front and back of house and 2 power ventilators on back side of roof. I also have small gable vents on each side of the house. I plan on putting in a whole house fan to cool the house down during the evenings. I was wondering do I have enough ventilation on the house, or would it be benficial to add a power ventilator at one of the gable vents or at both gable vents. Thoughts?