Bought 2 models for our front bedrooms as we're on a loud primary street. Mounted them yesterday and the difference in noise is incredible. I went for that 6.4mm laminated glass and positioned the models to the front from the window sill to give highest hole. Exterior noise and cold https://gunneruasvb.answerblogs.com/27002654/the-5-second-trick-for-noise-reduction-windows-in-chelsea