Re: [GBlist] Windows & UV Damage

[Stephen Thwaites <stephen@thermotechwindows.com>]

Faced with this problem i would try to find out what brand of Low e the
window maker is using.  I would then try to contact the technical
department of the Low e supplier. When find the right person, the
information flows like sap in the spring time.

Since the owners are likely living with clear glass windows at the
moment, perhaps the question could be rephrased "how much less damage
will there be with this low e?" ?

The Krochman Damage Function is the best comparator for evaluating
potential damage as some fading is due to wavelengths of solar energy
outside of the UV range and i believe this function considers this.  



Sarah Holland/David Foley wrote:
> 
> Dear Folks,
> 
> We're running some calculations that show us that we can lower the annual
> heating needs of a house in Maine by about 18% if we merely switch the
> south-facing windows from low-E glass with a low solar heat gain coefficient
> to clear insulating glass with a higher SHGC.  (East, west and north glass
> would remain low-E.  We haven't yet calculated if this change will increase
> cooling loads in summer.)  Making this change is about the only glazing
> option available to us with this window manufacturer.  My question is:
> where can I find good data on the potential for UV damage to fabrics,
> upholstery, etc., from the clear insulated glass?  There's an index, called
> the "Krochman Damage Function" which is a percentage of transmission of the
> UV spectrum, compared to outdoors.  The number is 64% for clear IG, and 34%
> for the low-E glass.  But what does this mean in practical terms?  Would the
> owners anticipate much more damage to the contents of the house?  Any
> real-world experience or hard data would be appreciated.  Thanks!
> 
> - David Foley
> --
> Holland & Foley Building Design L.L.C.
> 232 Beech Hill Rd.
> Northport, Maine 04849 USA
> p: (207) 338-9869 f: (207) 338-9859 e: hollandfoley@acadia.net
> 
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______________________________________________________________________
This greenbuilding dialogue is sponsored by REPP/CREST, creator of
Solstice http://www.crest.org, and BuildingGreen, Inc., publisher of
Environmental Building News and GreenSpec http://www.BuildingGreen.com
______________________________________________________________________