Bought 2 models for our front bedrooms as we are on a loud most important highway. Put in them yesterday and the main difference in noise is astounding. I went with the six.4mm laminated glass and positioned the units about the entrance of the window sill to give highest hole. https://stevek320lwh1.blogdal.com/27240556/considerations-to-know-about-energy-efficient-glazing-in-sw3