More Info on Down Fill Power?

The fill power rating is the volume (in cubic inches) displaced by one once of down.

For example

1oz of 650 fill power down displaces 650 cubic inches

In 750 fill, that same 1oz fills 750 cubic inches

In 850 fill, 850 cubic inches and so on.

The lower fill power down requires more down (in ounces) to fill the same area as higher fill power down and thus more weight. Otherwise it insulates as well as the pricey stuff, though it doesn't compress as well.

Oh, so my blanket is just as warm as a similar blanket with better down, at the cost of an ounce or so?

Sweet!

I was under some impression that I was losing warmth. For a 4oz item, down weight doesn't seem like that big a deal. It's not a 3lb winter bag, after all. If I start to worry about the weight in my pack, I'll drink a few gulps of water and feel better.

Well not exactly. Your blanket uses about 2.1 yards of nylon, probably at about 1.2oz/yard. Plus snaps and thread. So it probably has about 1.25 ounces of 650 power down. That would be as warm as a blanket with 1.08 ounces of 750 down, or .9 ounces of 900 down.

My point exactly. I'm ultimately talking about fractions of an ounce. I think fill power must be pretty important on a 0 degree bag, and pretty irrelevant on a down scarf, down shawl, down hat….

But, I mean, if you've gotta shave the ounces!

look on the bright side.
If you die of hypothermia using that 650 fill quilt, you would also have died using one with a 900 fill.

Should say "when"

Cool thread I like the pictures. That blanket is pretty lightweight and seems like a good deal. Nice way to boost a bags warmth. How big is it? There's probably no elastic or snaps right?

Bradford thanks for the explanation on fill weights pretty straightforward.

I checked the measurements. It's about 3.6 ft x 2.4 ft. So, in other words, it's a beach towel.

It has plastic snaps all along it's length for making it into a skirt type deal, which is good for not rolling out of it in the middle of the night. It also appears to have a drawstring as well. Impressive for the weight.

I will do a review when I get it if there's interest, although warmth will be speculative since it's summer.

For the weight and the price and the potential multi use, I like it.
Let us know how it works out for you.

It seems like you could tie it together and slip it into your bag. It would be a good way to keep your legs warmer (and cheaper than down pants).

I'll stick my Mont bell UL down jacket in my SB to cover my legs and it makes quite a difference for me. And its only 2.2 oz IIRC (of down)

Same concept! Just alot less expensive, since it's not as utilitarian as a coat.