when the frame effects are captured within the energy modeling software option the output results for vertical glazing assembly U value will vary based on window size. due to the frame effect.So which value we should enter in the Table 1.4.2B- Fenestration ? or we can enter center of glass U value ? instead of Assembly U value & put additional note that we have used separate frame & glazing inputs in energy simulation with frame details.
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
May 24, 2017 - 2:32 pm
I would enter the weighted average U-value of all the windows. This is what the reviewer wants to see.
I frequently see the glass and frames separated in the modeling software but the end result is not accurate.
Jean Marais
b.i.g. Bechtold DesignBuilder Expert832 thumbs up
May 24, 2017 - 2:45 pm
If your software does not calculate the assembly (frame + glazing) resulting rated u-value according to NFRC (ISO 15099), then use another software like WINDOW from LBNL. This will show you the "rated" assembly u-value. If you are trying to input the parameters into the program, do so, so that the assembly "rated" u-value is correct. A good trick for energyplus, is to use WINDOW to help generate the idf code required. This is typical for the baseline. It's a bit itterative changing glazing and framing parameters until the calculated assembly rated u-value is what you require it to be. Good luck.