Is mixing exhaust vents of any combination (ridge vents, roof louvers, wind turbines, gable louvers, and power fans) on the same roof when it’s a common attic OK to do?

A. Air Vent does not recommend mixing two types of exhaust vents on the same roof when it’s a common attic because it could result in short-circuiting the attic ventilation system in which one of the two exhaust vents becomes intake resulting in possible weather infiltration and less than optimal attic ventilation for the entire underside of the roof deck. There are generally four groups of exhaust vents: ridge vents, wind turbines, roof louvers/gable louvers, and power vents. Each group uses the wind differently. If any of these different groups of exhaust vents are mixed there will potentially be a short-circuiting situation. Short-circuiting the ventilation system will result in areas of the attic being bypassed (skipped). The system will still be venting, but it will not be performing optimally. Furthermore, weather infiltration is a very real possibility.  more