To loop back around to comment...

I have been shopping the Marmot line pretty heavily over the past few weeks, looking for a bag for SAR - in 3 seasons I use my quilts, I don't winter camp, but SAR is not necessarily about that. Base camp or wilderness bivouac, I am anticipating needing warmer gear without piling all three quilts in the backpack.

The Sawtooth you have is rated 15F but the comfort rating on the EN posted for the bag is 26F. (That's the comfort rating for women, the number for men is a bit lower.)

For my needs I surveyed the 0 degree offerings - of the 0 degree bags they list, I find variation in the EN ratings ranging from 17 to 0 - meaning not all bags are created equal. Rather than picking up the Marmot Teton 0 degree EN rated to 17F for comfort, I got the deal mentioned above on the Never Summer 0 degree, EN rated to 2F for comfort. I am anticipating that with layers and the bag I might get to -10 comfortably, and survive -20.

While the Never Summer I ordered is only 600 fp... it's not my preference to go out in winter at all, or use a bag. But the price and the rating are what they are, and at a later time if I find winter camping agrees with me and my economics improve, I may donate the bag to another SAR volunteer and upgrade.

You should post back and let us know how the Sawtooth does for you - I bet you will be happy with it. Marmot's higher end bags get great reviews.