Hi Mouse, Et All
Here on the east side of the cascade is high desert. <img src="/forums/images/graemlins/smile.gif" alt="" /> I put my down bags in large cotton stuf sacks and throw them up into my gear loft <img src="/forums/images/graemlins/laugh.gif" alt="" />which is the highest point in the house <img src="/forums/images/graemlins/wink.gif" alt="" /> and always the warmest and lowest humidity. <img src="/forums/images/graemlins/smirk.gif" alt="" />

BUT as Mouse said - if you have any option for mold <img src="/forums/images/graemlins/blush.gif" alt="" /> forming then you should be very careful where you put it, but right side up or up side down or on its side or rolled or stuffed <img src="/forums/images/graemlins/wink.gif" alt="" /> (loosely) makes no difference, just don't store a damp down bag and don't store them compressed. <img src="/forums/images/graemlins/smirk.gif" alt="" /> You can pile a bunch of them up, the weight on the bottom one won't damage the insulation, <img src="/forums/images/graemlins/shocked.gif" alt="" /> its compression stuff sacks that ruins bags, <img src="/forums/images/graemlins/frown.gif" alt="" /> especially damp bags. <img src="/forums/images/graemlins/blush.gif" alt="" />

A much bigger problem is: What if your bag is wet when you get up <img src="/forums/images/graemlins/blush.gif" alt="" /> and you have a tiny backpack <img src="/forums/images/graemlins/shocked.gif" alt="" /> and need to crush your sleeping bag to get your gear into it it? <img src="/forums/images/graemlins/confused.gif" alt="" /> I hate tiny backpacks. <img src="/forums/images/graemlins/frown.gif" alt="" />
Jim <img src="/forums/images/graemlins/cool.gif" alt="" />
These are my own opinions based on wisdom earned through many wrong decisions. Your mileage may vary.