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Re: GBlist: R-20 windows and other (possible) wastes




In a message dated 10/13/97 11:39:03 AM, you wrote:

<<Like Terry
said I think I'm going to take another look at air vented designs. >>

Hi John,

Always enjoy your posts.  They get me cooking.  I am going to take another
look at air vented windows.  I used them years ago in combination with
running the bulding slighty negative in heating climates.  Sometimes I used
sliding glass door replacement panels (two layers, air fill, double sealed
edge) with an air vented single glazing on the exterior.  In that way, the
edge sealed unit is exposed to less temperature extremes across the panel.  I
think I may see how they've faired over the years.  Other times, I reglazed
single pane prime windows with hardcoat low-e and added a storm.  I recently
modeled a number of configurations for a company that manufactures hardwood 9
over 6 double hung windows with brass fittings and pulley counter weights for
the restoration community.  They had been producing true divided lite windows
with tiny sealed edge units because it was being speced by architects.  They
were interested in alternatives that would perform as well without using
sealed edge units (they wanted to avoid the hassle and material weight of
installing sealed edge units in a divided lite window and to avoid the
inevitable fog problems of sealed edge units).  Hard coat low-e with a storm
gave them an overall U-value of 0.39 - substantially better than the sealed
edge - divided lite units because of the fantastic edge loss on the little
sealed units.  I plan to do some modeling of other air vented units to see
how good a perfomer we can get.  I'd be interested in any ideas the group has
on getting high thermal performance out of air vented windows.  I'll probably
dig out my old "dynamic window" papers that Yuil Gren wrote in the 80's.
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