WhirlyBird Turbine Vents
 

Has anyone seen a study that shows these move more air than any other vent of the same size:rolleyes:

Check out the MFG's websites Lomanco, Inc., Ventilation, Ventilators, Vents, Whirlybirds, Intake Vents, Exhaust Vents, Foundation Vents, Attic ventilation or Air Vent

I have checked it out, they don't make any claims like you would expect, if they really do better than flat vents.

I have one 14"rd. wind vent in a attic that is 800 Sq.' At a 7 mi. an hr. wind, it will move 4 times more than the 12" sq vent that was there before. This was
tested with a CFM tester that i use for balancing commercial kitchen in restaurants. Paul

Wind blowing over an open hole will vacume the air, what happens when it is stopped and I would like to know how that would compare on a day when there is no wind because that what really counts.

Your right the wind moving over a hole can pull a vacuum, but the same wind turning the wind vane moves a lot more air. and on a no wind day most roof vents are 6 or 8', mine is 14" and because its a flat roof i put it two foot in the air. This creates more chimney
action and moves more air. also it does not get under the snow and stop working like flat vents. I really like the wind vents

I'm just trying to settle an arguement for a couple of friends, everyone as an opinions and no one has proof. Still looking for that study or text book or something.
Thanks Neal