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re: aluminized mylar window treatment
17 aug 2005
anthony matonak wrote:
>it would be possible to install something automated. perhaps some kind
>of insulated window shutters or roll-down cover with a motor drive...
that does seem possible, but nobody seems to make a practical standard
commercial product like that. i've looked hard, and the ones i've seen
seem to be very expensive or have low r-values (eg 4 vs 20, including
an unspecified window--windows can be r8 by themselves) or leak lots of
air around the edges.
shurcliff's shutters and shades book describes a 5-layer aluminized mylar
shade that opens up with spaces between layers as it rolls down. this
would have a high r-value, but it's no longer being made.
the best homemade shade i've seen (in a washington's crossing pa barn
conversion by harrison frakur) had a u-shaped layer of aluminized mylar
with one horizontal edge permanently attached near the top of a window
and the other edge on a motorized roller near the top of the window, with
a roller-weight riding freely in the bottom of the film u. the roller
extended sideways into grooves on each side of the window. when dusk fell,
a photosensor would turn on the roller motor which lowered the film. you
could still see dimly out of the window. this might have been about r10,
with 4 reflective surfaces.
nick
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