I live a historic building in Brooklyn, with my bedroom window facing on to the very loud Brooklyn-Queens-Expressway. Prior to purchasing my Indow inserts, I had to sleep with a fan on high every night to drown out the sound of passing traffic. I had looked into replacing the windows, but because it is a historical building, it would have been an expensive and convoluted process. Now that I've installed my Indow insert, my room is almost pin-drop quiet. While I can occasionally hear a motorcycle or large truck passing, the constant hum of passing cars has largely disappeared. Even with my old window, which isn't exactly square and has been repainted several times in the past hundred years, the laser measurements were relatively straightforward to take and the resulting insert fit right in. I would thoroughly recommend Indow inserts for noise reduction, especially related to cars/traffic. I've yet to experience them over the winter, but I hope it will help keep my room warmer as well!