Simply just Talking, it generally requires the set up of some other pane of glass on the inside of the existing window. An item with a greater VT transmits far more obvious gentle. VT is expressed for a selection amongst 0 and one. The VT you'll need for any window, https://charliespjck.activablog.com/26114994/not-known-facts-about-slimline-secondary-glazing-belgravia