With the wind we have been having in the south I am getting some drafts entering the house, I have rechecked the survey we had done about 6 months ago before we moved in and there was a section that said about an unused air duct that needed closing up or removing, Just wondered how I would close that up, It is like a pipe that comes out of the floor about 10 inches and then has a 90 degree bend with what appears to be an open vent at the end.? any ideas