My design "wall" is really over one of my windows. We cut solid insulation to fit the window (cut for 3" x 3" holes in it so that the window doesn't sweat). Then I hung white flannel on a curtain rod over the insulation (they are each separate from the other). This works well for me. It is about 48" x 48". The flannel runs down farther than the window and I just pine those blocks on if I need them there.
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