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Re: GBlist: high performance on-site window test
I continue to lose sleep over these very REAL WORLD comments. I thank you
and my Nytol supplier thanks you. You are RIGHT about SHCG data. It is new
(relatively) compared to other lies about window and glazing performance.
On the brighter side, SHGC data that has been UPDATE and VERIFIED recently is
contained in the latest version of the WINDOW4 program's glazing library.
Since a new standard for measuring glazing spectral properties was developed
(thanks in large part to LBNL and FSEC) , the glass industry tested and
submitted samples for verification to LBL to enable NFRC-certified SHGC
values. I also believe that the latest version of DOE2 has the WINDOW4
drivers included and the updated glazing data library. Check with LBNL to be
Regarding whole product SHGC data, look for it on NFRC labels coming soon to
a contruction theatre near you. I know that Andersen, Velux and a few of the
major manufacturers are now labeling their product's SHGC data. The NEW NFRC
directory also has SHGC data included. Remember the "standard rant" about
looking for the label. (I wonder if more "users" started asking for this
information if the industry would actually want to GIVE it to us? I also
wonder how many oversized HVAC systems are installed daily due to outdated
gazing and solar gain data?)
<< I've been finding this to be much easier said than done. I'm trying to
get this type of information to select windows for the south side of
my New England house. Thanks to NFRC when I ask for whole-unit R or U value
I get it. When I ask for the solar heat gain coefficient (SHGC) they don't
know. I've been able to get this information for a couple different brands
windows, but that's it. It's next to impossible to comparison shop
R-value and SHGC values.
I was at my local lumber yard yesterday selecting a large window. The
giving me information had never heard of SHGC and told me that he usually
deals with builders and of course they don't care. He called the company
directly for me, but the salesman didn't know either so we got a technical
support number. They didn't know and gave us the number of their labs who
did give us the SHGC. This is typical of the difficulty I've had in getting
SHGC for glass.
I went to a home show once hoping to get window information. Of about 10
installer/dealers there, only one had heard of NFRC ratings. One guy even
told me that his hollow vinyl framed windows have a higher whole unit
than the R10 center of glass, because of the amazing insulation properties
of his vinyl. As you could easily guess he'd never heard of the NFRC.>>
Just shows to go you that there's still a market for pet rocks....
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