Bought two units for our entrance bedrooms as we've been on a noisy principal street. Set up them yesterday and the primary difference in noise is incredible. I went for that six.4mm laminated glass and positioned the units about the entrance on the window sill to give highest gap. https://angledtipprecisiontweezer98764.blog5.net/79058789/helping-the-others-realize-the-advantages-of-window-insulation