Autodesk Revit Architecture

[#1]

I am working on an IPD project and was about to send out area calculations of the glass panels used in my model when I came to realize that the materials are being calculated per FACE of object, not by area of object. 
example: a glass panel that is 5'-0" x 5'-0" should be 25 sf, but it shows up as what looks like the area of all 6 faces of the object.(above 50 sf)
How and why is this happening? 
How can I create a schedule of materials that makes sense in construction?

[#2]

Are you using "Parts" for the Model and extracting from them?

[#3]

No. not using parts. 

I made curtainwall panels and would like to know the quantity of glass within.

[#4]

I cannot reproduce the error. If I have a panel that is 5 feet x 5 feet, a material take-off schedule of curtain wall panels reports Material:area = 25 feet, as expected. I am using Revit 2013 OneBox.

[#5]

interesting. did you do a material take off on glass and frames in the panel for example? I was not doing a takeoff on the wall itself, but the materials in the panel. sorry if I was not clear.

[#6]

Here is a screenshot of an example.

The wall is 12 feet long. The wall area is correct: 120 SF.

There are two curtainwall panels int his wall. There are two layers of glass in each section of each panel, but the materials are not all the same. Some are glass, some are glass with spandrel behind and some are spandrel material. if I scheduel the materials, the quantities are off. it looks like all 6 sides of the object that is used for glass are being calcualted - maybe?

[#7]

Not easy to guess what could be without looking at the file. Probably is the way the curtain panel families are made. You said that each panel has double glass, therefore, there are two extrusions, maybe, both with materials. It all depends.

Another approach is to introduce two shared parameters in the panel family. Width and Height of panel. With those two values you could schedule the area of each panel more easily.

[#8]

After some further testing we have not been able to reproduce the behavior you are seeing. If you can, please upload a sample file (like the one the screenshots) with everything purged out, so we can get a better idea of how the panel families are constructed.