I am trying to replace a single-pane, clear glass window with an
aluminum frame, no thermal break with a double-paned, argon-filled,
low-e, tinted window with a thermal break in a parametric run. When I
enter in ASHRAE 90.1 U-factor and SHGC for the new window, the resulting
energy savings is significantly less than expected by a quick manual
estimation. I suspect that I am confusing NFRC U-factor for center-glass
U-factor given in the DOE2 glass library. I know the NFRC U-factor I
want to use which accounts for the type of glass and the frame type. In
eQuest, however, it appears that the glass and frame conductances must
be entered separately. Is there a way to enter the NFRC U-factor instead
or determine from the NFRC U-factor what the frame conductance should
be? Has anyone had similar problems?

Thanks,

Ben