Purchased 2 models for our entrance bedrooms as we have been on a noisy primary highway. Put in them yesterday and the primary difference in noise is astounding. I went with the six.4mm laminated glass and positioned the units on the entrance of your window sill to provide highest hole. https://sethjcshu.59bloggers.com/27259447/rumored-buzz-on-energy-efficient-glazing-in-sw3