[/quote] Valid point except nobody out my way has double-hung and have no clue what a storm window is(unless they are a transplant. I did replace our single-pane casement (crank to open) with double-pane sliders. The rooms are warmer in winter, cooler in summer, and the noise tranmission is seriously reduced (used to hear my neighbor start their car when I was in the back of our house, now I can't, nor can I hear the trash truck).[/quote] I fully agree with ya on noise too. As mentioned i replaced my windows with replacements....as well as closing in my porch with "new construction" giant sliding windows(8 of them, energy stars with a wider gas gap)....I have a Bose Wave System i leave on the porch...I can crank that thing....with windows closed I cant even hear it lol....same with outside noise....i can hardly hear it if at all.