Bought two models for our front bedrooms as we're on a noisy primary street. Installed them yesterday and the main difference in noise is amazing. I went for the 6.4mm laminated glass and positioned the units about the front of the window sill to give optimum gap. Decrease heating expenses: https://tysonbwntz.jaiblogs.com/53690524/getting-my-acoustic-window-upgrades-in-chelsea-to-work