We have had the window inserts installed in our downstairs for a couple of weeks now and all I can say is - THEY ARE GREAT! I could feel the difference the moment - literally the second - I put them in (they are that effective, and my windows were THAT drafty).I left on a work trip for a week shortly after installing them, and when I got home all I could do was remark about how much more comfortable the house felt. Also - you really can't see them, and guests definitely don't see them. The measuring process takes a bit to complete, but I'm sure it's why they are such a perfect fit (we ordered ~20 inserts for the whole house). Online portal was good and the team was responsive over email.