Acquired 2 models for our entrance bedrooms as we are on a noisy principal street. Put in them yesterday and the difference in noise is remarkable. I went with the 6.4mm laminated glass and positioned the units to the front in the window sill to give most hole. Time https://chee542koq6.win-blog.com/15237866/how-much-you-need-to-expect-you-ll-pay-for-a-good-retrofit-windows