down jacket compression

I recently purchased the MH Phantom down jacket and am wondering if there are any adverse effects, specifically the compression of the down at the shoulders (resulting in reduction of loft, warmth), when wearing a backpack over the jacket?

In my experience, wearing a pack over a down jacket will reduce the loft; clearly where the pack rests and where the shoulder straps ride, less clearly through tension on the outer fabric from the shoulder straps compressing the underlying down.

For me, the only time I wear my down jacket is in camp. Even in moderate sub-zero weather, if I am exercising at all, I sweat; I'm sure that the sweat condensing in the outer down layers reduces the loft and I also think this is progressive over several days. Things may be different at temperatures nearer -30 to -40 though.

I think this post sums things up well. The down will compress, especially under the straps and up the back, and at some point will become moist from sweat. I won't, however, be damaged and will bounce back.

Since I see you're in Minnesota I won't use my standard, "Why would you backpack in a down jacket?!?" but will suggest that fleece or even fiberfill are a better choice on the go, saving the down stuff for camp. But I don't hike in sub zero weather, so what do I know?

Whoops!--MN/NM/NH/HI--disgraphia kicking in today. Okay, unless you're above 12k feet, forget about backpacking wearing down entirely :-)

NM not MN.:) Hike a little faster, if it gets that cold, I am usually on my snowmobile, hotfooting it somewhere to spend the night when it gets that cold, then I wear activity subject gear and put the good stuff on when camp is reached.

It won't hurt the jacket. However, most hikers don't wear down while on the move.