Question about down coats

I understand the difference between down that 800 fill power and 500 fill power. The higher number is lighter and fluffier.
Here is what I don't understand doesn't it also matter how much down is in the coat? Not just quality but quantity must matter as well. I ask because I have a 650 fill lands end coat and a 700 fill marmot guide hoodie. To the hand the 650 is clearly thicker and firmer. I can tell you that it is a furnace on the coldest days. It seems to have much more down in the coat. Each baffle is stuffed.
How can I consider this when considering a new coat? Something more specific that feeling the difference by hand? Any thoughts are appreciated

Fill weight is what you're talking about. Different jackets will vary significantly in their fill weight. Some companies are good about posting both the quality of down (Fill POWER) and the amount in it (Fill weight). Good luck finding that with many though.

Backpacking Light does a fair amount of digging to find fill weights so try there if you're looking at a specific item. There's ROUGH indications of fill weight based on the naming conventions - Sweater = Very Light, Jacket = Medium, Parka = Heavy. It's tough though because unless you feel them as you note, you won't have a great idea of what's in it.

One thing I consider is the FP may not be all it's cracked up to be. 800FP is all the rage these days but I've noticed that several 650FP jackets "seem" warmer to me given a similar weight. IMO, the 650 is both more durable and seems to hold it's loft a bit better under the pressure a jacket gets in use. The 800FP might be great in a lab but more and more, the 650FP or the hybrids from Primaloft seem "stronger" and thus warmer.

Some companies put out how much they put in there, some don't. Most people don't worry or care about it so there is no huge push to quantify it. Also even overstuffing a jacket with down can make it not as good as another with the same or worse "fill power" down. Mostly compare across categories ie layering piece to layering piece, belay to belay.

But it does get tricky when you're trying to say compare a TNF L3 down jacket to a Patagonia Down Sweater Hoodie since they are both in the same category of jacket (layering down piece), both have 800 fill power, and are practically the same weight.

At the end of the day ¯\_(ツ)_/¯

Down fill refers to how much space an ounce of that particular down will take up. 1 ounce of 800 fill down will take up more space than 1 ounce of 600 fill down, providing better, lighter insulation.

When it comes to the overall weight of the jacket - that doesn't matter. A jacket can have heavier face fabrics and liners, more features, heavier zippers etc. but that doesn't mean it's going to be warmer.

What you want to look at is the fill power (higher numbers = more loft, more warmth:weight) as well as the amount of down that's used. For example, 10 ounces of 800 fill down is going to be much warmer and more lofty than 10 ounces of 600 fill down. BUT, if a jacket has 20 ounces of 600 fill and only 10 ounces of 800 fill, you may have a different situation.

It all depends. It's going to vary. Like someone said, some manufacturers will post the weight of the fill, others wont. If you want mega warm, go for something like a Patagonia Fitz Roy or maybe even an Outdoor Research Floodlight. Otherwise, most of the other "standard" down jackets are going to give you the same basic performance.

When considering your new coat, the first thing you need to ask your self is what do you want to use the coat for.

If you want a light-wight insulating layer for cool weather, then those ultralight super loft jackets will work well.

Once temps drop below freezing you will probably need a more substantial jacket, especially during periods where you are inactive, like belaying. This is where you are correct, the fill rating does not equate warmth.

What the industry really needs is a measured R-value like they have created for sleeping pads. For the most part, if you look at the pads, the thicker the pad the better the R-value, regardless of what it is filled with. This is the same with jackets, the thicker the baffle, the warmer it will be. There is no good measurement for this on most speck sheets, but weight is a fairly good indicator. Most jackets I look at are made with a similar lightweight nylon or polyester fabric, so the difference in wight can be a good indicator to how much down is being used for insulation.

Also be careful not to get a jacket that is too warm. I over did it when I bought my last jacket, and it is almost unusable until temps drop to close to 0F.

I also have long suspected that a heavy fill of, say, 650 FP down can handle more moisture before collapsing than the equivalent loft (and therefore fewer ounces) of 800 or 900 FP down. Can't prove it though. This is more of a concern when you're tent-bound for a few winter days and body moisture is building up in your bag.

Rab does a great job at listing not only fill power, but fill weight. Just like everyone else mentioned, it's more about loft and fill weight vs. fill power that provides an accurate assessment of how warm a certain down coat will be. The higher the fill power AND the higher the fill weight = Warm and fluffy. I can't tell you how many times I've called gear companies asking how much fill weight is in a certain jacket and they act like either they have no idea what I'm talking about, or they have to ask 17 other people to get a fill weight number. Unreal. Feathered Friends does a good job at listing both fill power & fill weight.

t.farrell wrote:So you end up talking to some idiot customer service rep who says well our jacket is 950 and we use 60g/m^2 of insulation.

Isn't this the information you really need?

If you only know the total mass of the down but not its fill power or the area it is spread across, then you won't know the loft.

For example: a longer jacket with the same mass and fill power would have less loft.

Sonething that seems to be missing from these replys:

Loft isn't determined by the down. It's determined by the jackets construction. You then fill the jacket with the amount of down needed to meet that loft.

There's also a thing called overstuff, which more down than is technically required is put in the same space. This can vary by manufacturer and product. Overstuff is MUCH less effective at increasing warmth than loft, but is often needed to ensure the garment lofts correctly all the time.

From the OP: a lower fill power will feel "thicker", and resist compression. The benefit of high FP is weight and compressibility. If you don't need that, why spend the money on the higher FP? From a warmth stand point equal LOFT (not weight of down) = equal warmth.

As others have mentioned, you're looking for the actual *amount* of down, measured by weight, in the jacket (this will roughly correlate with loft).

I've had good luck contacting manufacturers directly to get this info, either with the chat (fastest) or email features of their websites. Patagonia, OR, and Montbell were all recent successes. It's a pain, but worth it if you're investing in a jacket.