Bought 2 models for our entrance bedrooms as we are on a noisy primary road. Set up them yesterday and the real difference in noise is incredible. I went with the 6.4mm laminated glass and positioned the units about the entrance of the window sill to provide utmost hole. Secondary https://ufoartwork13457.blogrelation.com/32768346/considerations-to-know-about-energy-efficient-glazing-in-sw3