Hi All,
The subject here is "warmth of down garments relative to "loft" and "Shell stiffness"" <img src="/forums/images/graemlins/grin.gif" alt="" />.

Just before I start - remember its the fleece and longunderwear that keep you "cozy" warm, not the down. <img src="/forums/images/graemlins/smirk.gif" alt="" />

Down is a great insulater used in the right application Its the tiny pockets of air in the down that hold air still so it can be warmed. Let the air move around and those tiny pockets are no longer warm. Holding the air still in those pockets, and how thick the "virtuala" insulation layer is determines how warm a garmet will be. The virtual thickness of a garment depends on the ability of the shell to resit deformation. <img src="/forums/images/graemlins/smile.gif" alt="" />

The worst offenders are over jackets that compress the down around shoulders and chest, and backpack straps. There is mostly NO INSULATION in a high number down garment (800 down) when there is any weight on it at all. <img src="/forums/images/graemlins/blush.gif" alt="" /> <img src="/forums/images/graemlins/confused.gif" alt="" />

Down jackets with UL shells flap in the wind and are COLD. WHY? Because the 800 down does not have enough "body" to retain the shape "virtual thickness" of the garment, AND because the shells are made of very gossamer fabric.

A 650 down jacket (ignoring weight) can be warmer than an 800 down jacket - remember the number refers only to the first order "loft" and is not a measurement of "warmth", in fact commercially it means "Use less down". When you buy 800 down you are buying less down for more - light but not warm.

An 800 down UL sleeping bag is nice in a shelter, but could flap in the wind if exposed to wind and be worthless. <img src="/forums/images/graemlins/mad.gif" alt="" />Also if your pad goes flat 800 down offers little insulation under you. <img src="/forums/images/graemlins/blush.gif" alt="" />

My 700 down WM Super Kodiak with goretex shell weighs 1 pound more than a new modern one with 800 down and a UL shell - and in a sheltered space they may function similarly. <img src="/forums/images/graemlins/smirk.gif" alt="" />
BUT
I would bet that my OLD Kodiak bag would be a MUCH warmer haven in an exposed environment, than the new UL Kodiak would be. <img src="/forums/images/graemlins/grin.gif" alt="" />

Its a matter of the UL thing pushing manufacturers to make what people want, not what people need. <img src="/forums/images/graemlins/blush.gif" alt="" /> Fortuately in this country we have people who live where its cold and places like Cabelas and Bean still manufacture reasonable warm functional inexpensive gear that will outperform the ultraexpensive UL gear in every way but weight. <img src="/forums/images/graemlins/smirk.gif" alt="" />

Take my jacket collection for example. By modern standards my jackets are made of iron for a knight of the round table, but just try to find a rugged fully technical randonee jacket with powder skirt, double zippers, adjustable neck and high pockets for wearing with a pack thats UL. <img src="/forums/images/graemlins/smile.gif" alt="" /> You can't get that much function that light - period.

You will get more function from "regular weight" technical wear than from UL gear with the bells and whistles left off. UL is about going without. But going without warmth or waterproofness is not reasonable in a cold weather garment.
YMMV
Jim <img src="/forums/images/graemlins/cool.gif" alt="" />
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These are my own opinions based on wisdom earned through many wrong decisions. Your mileage may vary.