[esp-r] Re: construction

[Jon Hand]

Reported U values
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        I tried to create a new construction but failed.
        I have added 3 layers:
        layer Prim(db)  Thick(mm)  Description of material
      i  1       246         6.0            low_e glass
      j  2       0             12             air  0.17  0.17  0.17
     k  3       243         6.0            clear float
        ISO 6946 U h/u/d 2.846  3.111 2.555

but when i change the k layer to antisun 6mm
the value of ISO is the same.

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The reported U value will reflect the thermophysical properties
of the materials selected.  If the material associated with antisun
has the same thermophysical properties as the clear float then
the reported U value would not change.  If the glass layer has
a low-e coating then this property would be represented by altering
the resistance of the air gap (layer 2) so that the reported overall
U value matches the manufacturers specifications.

-Jon Hand