Epic or Quantum for Down Sleeping Bag?

Zeno,

I have 2 FF sleeping bags, both in eVENT. My original bag, a Lark was purchased in 1999. My new bag is a Vireo with 2 oz of overfill. Both have the 800+ down upgrade. When I ordered the Vireo, I also purchased the Volant Hood and a Hyperion Jacket, both also in eVENT.

I like the eVENT material, and breathability, but it is heavier than either the Pertex Quantum or the Epic. Personally, I have never liked Epic that much, but I only have experience with an older Patagonia Zephur Jacket. I would expect that the Quantum will not only be lighter, but the bag may loft better, breath well, and be reasonably wind and water resistant.

You may wish to read the Rock and Ice article and read about the Vireo and their comments about selection of outer material:

http://tinyurl.com/bwsh4

Rich

If you are going to use a bivy sack, then you may want the most breatable and lightest sleeping bag fabric. You would not weat to have an Epic sleeping bag and then an epic, goretex, eVent, etc, bivy over it.
Vapor transmission through multiple layers or the heaiver and more water proof materials may be to slow to prevent undue condensation.

-Ron

Just to confuse things more I have in the past been advised, by feather friends staff to use epic as the shell material for the sleeping bag over quantum or other types of nylon when using Bivys.

They said the interior bag shell needs to be hydrophobic in order to help push the moisture to the outer bivy.

Um, This might be an excellent topic for a backpackinglight research article including vapor transfer at different temperatures as well.