Going to get a new roof put on (I hope!) Anyway I thought I would try to locate any vents that are "dead" so that we could just pull them out.
I found this vent coming out of the AC return duct that goes up and through the roof. A lot of warm air was going out this vent! But the roofer couldn't understand why there would be such a vent, and neither can I. The air coming from the house and through the return ducting isn't all that hot.
If you are willing to offer your advice, please check out this webpage which has a couple of pictures of the vent from inside the attic.