[Greenbuilding] Desert windows - fiberglass?

[Bruce Donelson]

Dan: Beside U-value, you should check the solar heat gain coeficient.

I think that either vinyl or fiberglass would hold up pretty well. They
should both have UV protection built in. Even if the surface was to oxidise
a little, the window would not get brittle until it had progressed pretty
far into the material.

You could check some windows that have been around a while. Vinyl and, to a
lesser extent, fiberglass have been installed in your area for a number of
years now. You could see if any units are failing.

The reason that thermally broken aluminum frames are difficult to find is
that they still have terrible thermal characteristics.

Your exterior shading system will do much to block unwanted heat from
reaching the window.

Bruce Donelson
A Better Builder




Looking for windows to put in a new house in Phoenix, with a very low
U-value (0.3 or less) to fight against 115 deg F heat.  I'm concerned
about the durability of fiberglass frames in that intense UV
environment.  In my experience, anything synthetic left in the sun
turns to powder in a few years.  Are fiberglass actually OK?

Desert window options:
1. Fiberglass frames - UV degradation?
2. Aluminum frames - hard to find thermally broken Alu frames for
residential windows, otherwise splendid
3. Wood - forget wood in the desert. It will last a year
4. Vinyl - avoid vinyl (see dialogue elsewhere); same UV degradation
as fiberglass?

FYI: also have a good shading scheme, exterior blinds, etc.