Fill type vs. Over Fill

[Bradley]

I see that there are a couple of options for fill

Fill Type 800+ or 900+
I'm not sure of this difference, as compared to Overfill.
Or how they would compare as a choice one over the other.

Thanks for your help.

[CTGuy]

I'm curious about this too weather it would be better to order the winter incubator with 800 fill down with 3 to 6 ounces overstuffed or 900 without overstuff?

[silentorpheus]

there was a recent thread where they clarified this (it's confusing, I know) but the short of it is:

800 vs 900 fillpower - the 900 fill power is a nicer higher quality down. That means that when using the same amount (in ounces) of down, the 900 will loft more, providing more insulation and thus a lower temp rating, than the 800 fp down.

Overfill - this is where you actually add more down, by weight, of either type (800 or 900). 1oz overfill means that you add one extra oz. of overall weight to the quilt by adding extra down to the chambers. This does add extra warmth - to a point. There is the law of diminishing returns on this one. The chambers/baffles of the quilt are made to accommodate a certain amount of down. If you add to much, they get full, the extra down can't loft up enough, and you lose the effects.

As far as which to choose over the other, that's sort of a personal choice. The 900 fp down is a no brainer over the 800, if it's in your budget. Same weight, same basic bulk, packability wise, but a warmer quilt.

Overfilling on the other hand can get you a few more degrees, but at the trade off of extra bulk and extra weight. And you can only overfill so much before you go too far. But it can be helpful if you're trying to squeeze an extra degree out of a sleep system.

Hope that helps!

[Bradley]

Hope that helps!

Most Xcellent

Thank you so much

[Str1der]

Another possible benefit of overfill is that you will be less likely to have to adjust the down in the quilt. Sometimes, down can accumulate in a lower hanging section and be slightly less dense in a higher section. Overfill tends to reduce that from happening; however, this is fairly subjective and differs from quit to quilt.

[tjm]

A few comments:

The loft [thickness] of the quilt determines how well it insulates.

So you start with a length and width of the quilt shell and then determine the loft you need based on the expected temperatures the quilt is going to be used at. You sew the quilt shell and it has a specific volume {length x width x thickness [loft]}.

This gets you a volume that needs to be filled by the down. You do the math based on the down fill power [oz per cubic inches] times quilt volume [cubic inches] to determine oz of down you need to add. So if you are using 900 fill then you need fewer ounces of down to fill the same volume than if you were using 600 fill.

Overfilling more than the required amount of down does not cause the quilt to have more loft; to some extent it may guarantee that full potential quilt loft is attained but, in the end, the maximum loft is limited by the quilt dimensions.

So you can fill that quilt volume with 600, 700, 800, 900 fill power down and the quilt will still provide the same amount of insulation because the loft is the same regardless of the fill power down you used.

The only difference will be in the weight.

The "900 quilt" is not warmer than the "600 quilt" but the "900 quilt" does weight less than the "600 quilt"

I have read articles that claim the higher loft downs lasts longer but I am not convinced. My very old down comforter was probably a low quality fill power and is still plenty warm after many years of use.

The only time I would pay for overfill is if I thought the manufacturer was underfilling the quilt. Even then I think more than an oz of overfill is wasted money since it is doubtful that they are underfilling by 600-900 cubic inches.

http://www.mammut.ch/images/Mammut_Sleep_well_pt1_E.pdf

http://www.mammut.ch/images/Sleep+Well_down_pt2_E.pdf

It is the trapped air that insulates you, not the down, the down is just the method of trapping the air.

[Pitch]

As down gets beat up over time, I believe it loses a little loft which will result in degradation of temp rating.

I also believe overfill combats this by providing more potential loft even as the down in the bag starts to lose its spring over many many years of use or possible abuse

- in my eyes it is the only reason for overfill - but with that said I'd likely throw in 1 oz of overfill if given the option.. Somebody who knows more about this step on me if I'm wrong ;-)

-XexorZ

[Barefoot Child]

I have always believed that the lofting strength of any down depended on two things....how long and how tightly compresseed the bag or quilt was stored, and the degree of cleanliness of the down inside the chambers ( by this I am referring to the dirt and accumulated body oils that are transferred from the sleepers skin or clothing into the down through the fabric.

And as a result I have always tried to store my bags and quilts by hanging them up in my closet uncompressed and attempting to keep them as clean as possible. YMMV/HYOH

[Festus Hagen]

Yep it can be confusing... I have two EMS jackets, one is a 650 fill Glacier jacket, the other is an 800 fill Ascent (technically a sweater). The 650 fill jacket is "jacket weight", the Ascent is "sweater weight" thus the Glacier is a lot warmer with more loft... but the Ascent packs down to nothing which I guess justifies the price tag. I use the Glacier pretty often, the Ascent only comes out if I'm backpacking or kayaking.

[Mountain Gout]

Interesting thread...