[Bldg-sim] aluminum window frame U-values

[James Hansen]

I was wondering if anyone would be willing to share thermally broken
aluminum frame conductance values that they've been using in recent
Windows5 center-of-glass calculations.  I don't have information on the
particular aluminum frames for my current project, so I don't really
want to try and learn THERM quite yet.

 

Most of the older documentation online that I've found shows that
thermally broken aluminum frames typically have a U-value of about 1.0.
This jives with one of DOE-2s window entries for a PPG glass with a
frame conductance of 0.94.

 

Almost every commercial building constructed these days is made with
aluminum framed windows...I just have a hard time believing that
manufacturers haven't figured out better ways to insulate the frames.
With vinyl and wood having U-values < 0.4, I have to think that aluminum
frames should be able to at least approach 0.5, if not lower.
Unfortunately not a lot of manufacturers of aluminum frames post their
thermal characteristics.

 

What are people using?

 

Thanks in advance!

 

GHT Limited
James Hansen, PE, LEED AP

Senior Associate

1010 N. Glebe Rd, Suite 200

Arlington, VA  22201-4749

703-338-5754 (Cell)

703-243-1200 (Office)

703-276-1376 (Fax)

www.ghtltd.com <http://www.ghtltd.com/> 

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20110301/217e7fa5/attachment.htm>