Soundproofing - My experience
Well, as many of you know we built a house but found the noise coming through the windows (builders grade) too much as we dont live that far from an interstate. I wanted to share my experiences as I gained so much intell from folks here but also never found an answer prior to my spend.
We ended up getting exterior storm windows with 1/8 inch non laminated glass and have about a 2 inches gap between those and the existing windows. WOW! What a change in sound... in the room we installed it in as a trial run we cant now here the exterior interstate traffic at all or very very rarely. We had the Provia aluminium storms installed and it worked out at about $200 per window installed (ours are about 40 inches wide and about 80 inches high). It was a fraction of the SoundProof windows company that wanted $700 and another local company that wanted a similar amount.
Anyway, thought I would share my experience.