[masraum]

Originally Posted by Gogar

In my basement I used to have a storm window/ interior window gap that was about 3 inches and that particularly large air gap was an unintended but very fortunate way to keep noise from transmitting through the windows in either direction.

That's how the acoustic window inserts seem to work, at least for one of the places that I looked. You have your window of whatever sort installed, and then they send you a pressure/friction fit window to fit the inside of your window opening that you install on the inside. The place that I looked used a single large pane of glass like a windshield, 2 sheets of glass with a sheet of some sort of plastic between them that acted like a extra thick window.


But I guess there are other places that will sell you what is essentially a second window that goes close to the inside of the house.