On Fri, 03 Dec 2004 16:07:13 GMT, "bill a"
scribbled this interesting note:

"Zypher" wrote in message
hlink.net...
I've always wondered if those 'turbine ventilators' really work? Do they
really move that much more from the attic space than say a dormer might?


In the past, I've read that they are mostly a gimmick.
I think that a similar "stovepipe" type of structure with
a weather cap would do just as well. Some vertical
height would seemingly let it draw like a flue, as
opposed to the low profile static vents they sell at HD.
I haven't seen any recent tech info on this, though.
Bill


http://www.naturalhandyman.com/iip/i...fattfan3b.shtm

is one place with some information about this. Here is an excerpt from
another site:
http://www.homeimprover.com/articles...entilation.htm
"Turbine ventilators are wind-driven devices which are designed in
such a manner that wind from any direction causes the upper portion of
the ventilator to rotate. As the turbine rotates, or spins, a reduced
air pressure in the stack draws hot or humid air from the attic
space."
This last piece seems to explain it better than most any other source.


--
John Willis
(Remove the Primes before e-mailing me)