Its a "planned community" and at the front of the house, so removing it isn't an option. I have a sun screen on the front of it, so you really can't see in.
I want to cover it, so I can have a did/gg "bunker", and there will be two columns back there with rear surrounds mounted on them.
I had not considered the thought of something growing in the closed space (primarily worried about sound issues). I am in Phoenix so we have very little humidity. If I cover the window with felt and insulate the wall, you think I could have mold issues?