Cardinal Glass Double-Pane IGUs
I am considering Cardinal Glass double pane IGU’s made with their LoE 366 glass (u=0.29). There is an option to add a 4th coating, called i89, that will reduce the u to 0.23 for an air-filled unit. Can anyone give me an idea of how much that i89 might add to the cost of the window? It has been difficult for me to get answers from my supplier. Climate zone 5 and I’m just trying to get a sense of the cost effectiveness of this added option.
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