Catalin:

I'm confused. I assume you are reading data from other workbooks (vs worksheets, which would be contained within the same workbook, and therefore always accessible.) However, to read the data, you must have the source workbook open, and therefore you should be able to read the row height at the same time, correct?

I agree with Tony, a macro which opens each source, reads the data and rowheight, and writes that to the collector and then closes the source, would seem to be the way to go.