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Table 1 – Whole Window U-factors of Sample Windows
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[TD="width: 24%, bgcolor: #C0C0C0"]Aluminum frame w/o thermal break[/TD]
[TD="width: 25%, bgcolor: #C0C0C0"]Aluminum frame with thermal break[/TD]
[TD="width: 18%, bgcolor: #C0C0C0"]Wood or Vinyl Frame[/TD]
[TD="width: 33%, bgcolor: #ffffff"]Single Glass[/TD]
[TD="width: 24%, bgcolor: #ffffff"]1.30[/TD]
[TD="width: 25%, bgcolor: #ffffff"]1.07[/TD]
[TD="width: 18%, bgcolor: #ffffff"]n/a[/TD]
[TD="width: 33%, bgcolor: #ffffff"]Double Glass, ½" air space[/TD]
[TD="width: 24%, bgcolor: #ffffff"]0.81[/TD]
[TD="width: 25%, bgcolor: #ffffff"]0.62[/TD]
[TD="width: 18%, bgcolor: #ffffff"]0.48[/TD]
[TD="width: 33%, bgcolor: #ffffff"]Double glass, low-e, (E*=0.2), ½" air space[/TD]
[TD="width: 24%, bgcolor: #ffffff"]0.70[/TD]
[TD="width: 25%, bgcolor: #ffffff"]0.52[/TD]
[TD="width: 18%, bgcolor: #ffffff"]0.39[/TD]
[TD="width: 33%, bgcolor: #ffffff"]Double glass, low-e, (E*=0.1), ½" air space[/TD]
[TD="width: 24%, bgcolor: #ffffff"]0.67[/TD]
[TD="width: 25%, bgcolor: #ffffff"]0.49[/TD]
[TD="width: 18%, bgcolor: #ffffff"]0.37[/TD]
[TD="width: 33%, bgcolor: #ffffff"]Double glass, low-e, (E*=0.2), ½" space with argon[/TD]
[TD="width: 24%, bgcolor: #ffffff"]0.64[/TD]
[TD="width: 25%, bgcolor: #ffffff"]0.46[/TD]
[TD="width: 18%, bgcolor: #ffffff"]0.34[/TD]
[TD="width: 33%, bgcolor: #ffffff"]Triple glass, low-e, on two panes, ½" paces with argon[/TD]
[TD="width: 24%, bgcolor: #ffffff"]0.53[/TD]
[TD="width: 25%, bgcolor: #ffffff"]0.36[/TD]
[TD="width: 18%, bgcolor: #ffffff"]0.23[/TD]
[TD="width: 33%, bgcolor: #ffffff"]Quadruple glass, low-e (E=.01) on two panes, ¼" spaces with krypton[/TD]
[TD="width: 24%, bgcolor: #ffffff"]n/a[/TD]
[TD="width: 25%, bgcolor: #ffffff"]n/a[/TD]
[TD="width: 18%, bgcolor: #ffffff"]0.22[/TD]
[TD="bgcolor: #C0C0C0, colspan: 4"]*E is the emittance of the low-e coated surface.[/TD]
[TD="bgcolor: #C0C0C0, colspan: 4"]Source: 1993 ASHRAE Handbook: Fundamentals, (Atlanta, GA:American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Incorporated, 1993).Note: These are example of whole window U-factors of 3 ft x 5 ft windows. U-factors vary somewhat with window size. Ask the dealer for the specific values for the window you are looking at.
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