When using WINDOW 5 software to calculate the overall U-value of a window assembly, including the frame, I have a big question regarding the number of calculations needed. Suppose that for the building I am working there is only one type of window but the dimensions vary, there are five different sizes of windows, all with the same frame. Do I have to calculate the overall U-value for each window size? Or do I use a standard size?
Any suggestions greatly appreciated.
Yes. Is the short answer. You can take a look at ASHRAE Fundamentals for more insight. As for me, I enter in the %Glass to wall in Trace700 and enter the U-assembly that the Arch's specify...for LEED design modeling. Once you have actual submittals from construction, then I use the manufacturer provided U & SHGC's. I try not to calculate these values since it's empirical, whereas manufacturer's have testing to back up their claims.
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