Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
When the latest edition (Tenth Ed.) of the IES Lighting Handbook came out, the LED replacement lamps for 4' fluorescents were still kind of in the "Wild West" phase, with lots of new product and performance claims but little test data. The DOE's "CALiPER" testing program has addressed this quite a bit; you may find some info in their detailed reports to at least offer some guidance on part one of your question.
As for part two, the manufacturer's data will tell you how much less (possibly) energy the LED lamp uses, but remember that the input watts are only part of the story when evaluating direct replacement of one light source for another.
