Hi
According to the review for our Project in Germany, we have to provide information to confirm that the framed assumbly U-value is based on either the LBNL Windows 6 program, or a simulation program that approximates the NFRC rating methodologies.
The frame U-values and resulting assembly U-values were calculated using the EN ISO 12631. Is this sufficiently close to the NFRC rating methodologies?
Thank you!
Sarah
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5874 thumbs up
May 23, 2024 - 11:23 am
I don't know if it is equivalent or not. It is incumbent upon you to make the case of equivalency to the reviewer. If that is the European standard manufactuers use to calculate the whole assembly U-value then it should be acceptable. Typically one relies on data provided by the window manufacturer. So just make sure your are using the whole assembly value and not the center of glass value. Depending on the energy modeling software you are using you may be able to simulate the window performance as whole assembly or by separate components for the frame and glazing. I would guess that is what the reviewer wants to see - that you are correctly modeling the whole assembly performance - just keep in mind there are several ways to do so.