Quote:
Everytime we sleep we emit about 1.5L of moisture over a 7 hour period - more if we are sweating to any great degree. Every down bag will absorb this moisture and lose some of its loft and hence ability to retain heat until it can be dried out


Oddly enough my quilt never weighs over three pounds MORE, each morning. I'm pretty sure I'd notice that. Winter camping aside, I would not assume that moisture sweated out is automatically trapped by a bag. It's vapor, and (obviously) most of it passes through the material.

Don't trust this often-repeated statistic and ones like it without a quick grounding in common sense. Winter expeditions report stuff like this; not in my 3-season experience however.
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- John