you know what I am talking about...the big round exhaust like pipe that has a rotating cover/top.

At first I thought it's kitchen exhaust, but I saw some on top of car garages.

What exactly are those things, and why do they rotate at different speeds?

5/9/2006 9:09:13 PM

attic vent cover

5/9/2006 9:10:28 PM

the force of the hot air escaping from the attic makes it turn

5/9/2006 9:12:10 PM

some houses had like 3 on top...

5/9/2006 9:13:30 PM

probably a building code based on either attic area or volume

5/9/2006 9:15:43 PM

why does it need to rotate?

5/9/2006 9:16:31 PM

so you know its open

5/9/2006 9:17:08 PM

your house would explode without it

5/9/2006 9:19:33 PM

a full length ridge vent is ideal. a pipe roof vent is next best. it needs to be as close to ridge as possible. i would assume that rising air starts it spinning, once it's spinning, it blows out air faster, thus venting the roof quicker and causing more currents to rise up from the soffets.

5/9/2006 9:21:18 PM

exploding houses are no joke

5/9/2006 9:28:52 PM

The rotations of turbine vents are created by wind, which is a cheaper/simpler alternative to an electrical ventilation system. The rotating 'blades' pull the hot, humid air out of the attic.

http://www.askthebuilder.com/442_Roof_Turbine_Vents.shtml

[Edited on May 9, 2006 at 9:50 PM. Reason : url]

5/9/2006 9:46:20 PM

oh snap!

5/9/2006 10:10:20 PM

Without good ventilation your house will not explode. It will, however, force you to replace the shingles in 6-8 years.

5/10/2006 10:28:15 AM

does to. i seen it

5/10/2006 11:49:52 AM

helps air out the scent of curry.

5/10/2006 2:08:40 PM

^just don't install it backwards

5/10/2006 2:29:40 PM

^wtf

5/10/2006 2:49:03 PM

according to that super bowl bud commercial, you can use them as grills

5/10/2006 2:58:41 PM

^^^ whoa

5/10/2006 6:49:45 PM