Notice: These values are for the center of glass only. They need to only be used to match the result of different glazing varieties, not to compare total window items. Body selection can significantly have an impact on performance. These values stand for double glazing using a one/two″ air gap. https://city-fermanagh79012.imblogs.net/86406488/5-tips-about-secondary-glazing-windows-you-can-use-today