Overstuff? How much does it help?

[Karl]

Isn't the idea of overstuffing down insulation just to compensate for down escaping through seams and fabric? I.e. more of a thing to give the garment / quilt a longer life in the promised insulating range/temperature, rather than pushing the piece into usage at lower temperatures?

[HappyHiker]

I still don't quite know if I should order any overstuffing in my hammock after all this...

Personally, I'd vote yes. For a relatively small increase in cost ($8-10 oz) compared to the overall cost of the item it's an easy decision for me.

OK, I never got an answer on this question from a year ago, but I think the answer is apparent. That is, if Mad77 is correct - and I have no reason to doubt him and he says "There are thick scientific papers on this", then the answer to my question is "Yes, a 3" quilt pulled to tight and compressed by half will be just as warm". It appears then that you can choose either maximum loft from a given amount of down or half the loft it is capable of giving, and the warmth will be the same. That is the implication of the scientific papers Mad77 mentions.

I think your conclusion is a sound one.

The "papers" he refers to I believe are as follows: 1948 NIST, the Natick study, the Journal of Engineered Fibers and Fabrics Volume 2, Issue 2 - 2007, as well as what Richard Nisley has researched (much of which can be found over at Backpackinglight.com) if you're inclined to do further reading on the subject.

I would have thought it warmer to get as much loft as you can from a given amount of down, but maybe not.

I agree, and from what I have read from these studies this is generally true, but not by a large amount. What I get from the studies and discussion of them is that the insulative properties remain basically the same due to several different factors, up to that 50% compression point. The basic underlying idea is that in a weight vs warmth scenario you can get more warmth for less weight by overstuffing the down vs the added weight of additional material in a shell/baffles required to allow the down to loft to it's fullest potential.

Isn't the idea of overstuffing down insulation just to compensate for down escaping through seams and fabric? I.e. more of a thing to give the garment / quilt a longer life in the promised insulating range/temperature, rather than pushing the piece into usage at lower temperatures?

I have down sleeping bags that are ~ 25+years old (550 fill which contains a higher count of feathers than the newer 800+ fill), and over the course of that time they have lost a few feathers and down plumules - nowhere near an ounce (possibly a few grams but I doubt even that much). If I had a bag that lost ounces of down I wouldn't be happy about it at all. Overstuff generally increases the temp rating and reduces possible shifting of the down. All good in my book for the relatively low cost of the extra down.

[neo]

How much does overstuff in a down quilt (top or under) actually effect its performance?

in my opinion better to just be the next degree lower temp quilt and you will not be disapointed or let down like i amneo