I'm remodeling my basement, knocking out a couple partition walls (non-bearing) and removing a drop ceiling and will be drywalling it. There are currently no HVAC vents in the basement. I have access to the ductwork in the area where the drop ceiling was, a supply and a return trunk. These two trunks hang belong the joists. And I can probably get access to some of the other ducts in the ceiling joist space that is already drywalled.
My question is how should I go about determining where to cut in the new vents? The area is L-shaped. I'm assuming it would be best to have both a supply and return. The basement doesn't really need to be cooled in the summer and the humidity is not bad. It does get a bit cool in the winter time during the WI winter.
What kind of vents would be best? I'd like something that would close tightly . So I could close the supply during the summer, but keep the return open. I'm imagining that that would work the best to drop the humidity out of the air but not make it crazy cold.