Passive Solar Design, Windows: SGHC vs. U-Value

 Hi there!

For a non-furnace home that tries to rely on passive solar alone, what kind
of windows would you want on the south-side? Would you prefer a high SGHC
over a low U-value?

For example (www.efficientwindows.org) a single-pane window has a SGHC of
0.76 and a U-value of 1.25 whereas a double-pane, low-e window's SGHC is
between 0.30 and 0.55.

Does anybody know about a manufacturer that carries a window with U-value of
0.30 and SGHC of 0.55?

Thanks!
   chrism @ project licht 'n stein

 
I wouldn't try to rely on passive solar alone, unless you happen to be
located in the sunny Southwest USA, or someplace like that elsewhere on
the globe. Most of the classic passive solar houses and design rules for
classic passive solar houses don't work in any other climate. There are
much better design options. Read the archives of alt.solar.thermal


Given a typical Low-E U-value of .30, the single pane lets OUT 4x as
much heat, while it lets IN 2.5-1.3 x as much solar gain. During the
heating season more than half the day is spent letting heat out, with no
sun coming in. Put the single pane on a collector, perhaps, but use
Low-E for the windows.


This is a question I want to know about, too. Pretty much all of the
Low-E windows I've looked at, in the Northeast USA, where solar gain is
desirable, have SGHC's that seem more appropriate to the Southern USA
(airconditioning), or to East and West walls in the Northeast. They also
have fairly poor VT (0.6 or so). I want some decent windows for my South
wall which have a low U value with relatively high SGHC and VT.

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