I recently purchased a portable (stand alone) air conditioner. My problem is, because of the type of windows in my unit I can't vent it out a window as most people do, and because of my HOA rules I can't vent through a wall either. However, I've read that these portable units "can" be vented into a crawl space, drop ceiling or attic. I've decided to vent it to my attic which is well ventilated using affordable PVC pipe and do the work myself; unfortunately the diameter size required by the manufacturer is 5 inches for proper venting of the portable unit. I've looked locally (HomeDepot, Lowes, etc.) and that diameter PVC can't be found? Can anyone direct me to a local supplier (San Diego area) that would sell 10' lengths and fittings for 5 inch diameter PVC? Also, has anyone ever heard of "oval" shaped PVC so that I can put the vent in a 3-1/2 inch stud bay instead of building a chase like I'm planning to do now? Or is there some other type of material that might be better suited for a project of this type? I'm open to suggestions from anyone who's tried to do this, or has knowledge of this type of venting for a portable A/C unit?