Help with Puffy design

Terminology: If a jacket is sewn through then it doesn't have baffling, as baffles are the pieces of fabric that form the sides of the down chambers. I understand your post, but people will read it more clearly if you don't use the word baffling/baffles to describe sewn-thru garments.

Onwards – All else being equal, more seams means more cold spots but you also need to consider down compression and down distribution. Smaller chambers will normally compress the down a bit more, but as the work of Nisley shows it's a pretty minor effect at normally encountered levels of compression. Down distribution is better with more chambers to hold the down in place. This may cancel out the extra thin spots.

Overall, I wouldn't focus on the sewing pattern unless you're comparing sewn-thru vs. baffled/box designs. If you're looking at all sewn through jackets, I'd keep it simple at look at ounces of fill (and quality if they're not all 800).

The Alpine Light is a fine jacket. I've owned one. It's not a lightweight champ at 35% down by weight but it's a well rounded tool now that they've knocked a few oz of features off in the last year. The biggest downside is that the Mirage exists. Montbell's Mirage jacket is 0.5oz lighter (parka vs parka), contains substantially more down (5.3oz of 900FP vs 4.3oz of 800FP) and utilizes a warmer baffled construction. It's even 3" longer in the torso which is good as the Alpine Light is marginal in length. So the Mirage is lighter, warmer and longer. The only real reason to get a Alpine Light Parka is because it's cheaper ($200 vs $309) or slightly more durable (20D vs 7D). I mention the parka because when you're getting a jacket with 4+ oz of down it's a pretty good idea to get the hood.

Montbell is pretty much owning the down jacket market these days. Other manufacturers make darn nice down jackets too, but no one is offering such high quality pieces at such low prices. Personally I'm eying up the new Frost Line parka. It's also not a SUL champ at 34% down by weight, but it offers a lot for the 7oz penalty over the Mirage. It's also baffled and offers 12% more down, an extra inch of length, a more durable 30D nylon shell and it's ninty bucks less ($219).

The Alpine Light is a lot of jacket for the warmer half of the year, yet not quite enough for winter use. I personally would go with something in the 2.5-3.5oz down range for the warmer 6 months (ie. UL Down Jacket) and then something 6+ oz fill like the Frost Line for the colder half.

I'd agree with what dan said, and I'd steer you toward a mirage, if funds allow. Montbell does have some of the best puffies around from the lightest weight to the heavier winter pieces.

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All posters, to this point, have provided good information to Jimmy. I just want to expand on what they said relative to baffle types and patterns.

Testing jackets, with a similar amount of down fill, based on the baffle pattern and type, is difficult. I use an environmental chamber, an iso-thermal plate, and thermal imaging. The following is a baffle thermal analysis I recently did on the Montbell Mirage. The jacket is shown with the resulting down distribution after fluffing it and then wearing it for 8 hours. The top of the image is the top portion of the jacket back; it is lying horizontally in the thermal chamber. Note that the laws of gravity apply even to goose down (smile).

To the casual observer, the Montbell Mirage appears monolithic, but both the down's varying density and distribution in the baffles forms complex patterns of thermal resistance.

My tentative testing indicates that up until the range of about 9 oz. of fill, the baffle pattern and types seem to be relatively insignificant variable in jacket performance. Wearing a wind shirt or hard shell over a down jacket makes each baffle type and pattern perform about the same.

Thank you all for such thorough answers and recommendations. It is always nice to be an informed buyer when I make larger purchases.

Also great to see the scientific evidence to back your purchase.

Much appreciated folks, jimmyb

Cool photo and tools Richard, you have the best toys : )

Montbell Mirage is box construction with 5.3 ounces of down, way less than the 9 ounces you mention

It looks like it's leaking heat where the baffles are, even though it's box construction. It looks like it's sewn through.

Another thing bad about sewn through, is if you pull on the jacket vertically, like gravity does, it tends to flatten out the baffles, reducing the loft. Box baffles will do this less. Theoretically. I wonder what reality is.

Is your picture taken of a vertically oriented jacket, suspended from above, like it's actually worn?

I wonder what the picture would look like if you had a windbreaker or whatever over it, comparisons between sewn through and box…

I'm going to argue with Dan on terminology. A baffle is simply anything used to restrain the down. Sewn thru indicates there is no additional fabric strip to allow and promote full lofting. Box-baffling is the construction method used where a fabric strip creates a 4 sided (boxed) chamber for the down.

The Mirage is probably the best all around winter jacket I've seen assuming your usage won't test the 7d shell fabric. That said, Richard's research is fairly solid and he's most likely right that under that 9oz heavy winter coat mark, baffling isn't a major factor. Still, I'd be wary of anything with the really small micro-baffling. I've heard anecdotes of the Rab microlight (5oz of 750fp down) which should be in the category of a MB alpine is actually maybe just slightly warmer than a MB UL parka. I'd say a lot of that is due to overuse of baffling (patagonia down sweater is a similar style to the rab).

n/m

First: let's make that we talk about exactly the same things because while some say that baffling include sewn-through, others say that baffling doesn't include sewn-through. So for me it doesn't matter, but somewhere one has to agree wether or not to include sewn-through.

So, second, Richard, was it or wasn't it included in your analysis ?

Woubeir,

I compared both sewn-through and non sewn-through with various geometries.

OK, and you used the term 'relatively insignificant'. How much is 'relatively insignificant' ? BTW, my winshirts and rain shell are sized for active situations and then I don't need my down jacket; it's used only in static situations and my windschirt and rain shell are not sized for going over the down jachet then.

Oh, and that 9 oz. of down is interesting as I know a certain manufactured claimed that point already was at 5,3 oz..

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"I've heard anecdotes of the Rab microlight (5oz of 750fp down) which should be in the category of a MB alpine is actually maybe just slightly warmer than a MB UL parka. I'd say a lot of that is due to overuse of baffling (patagonia down sweater is a similar style to the rab)."

Dustin, I was surprised to read this statement. I am under the impression that the additional baffling adds warmth by improving the distribution of the down…

Woubier,

This topic should be old news.

What should be “new news” is that I plan to use insulation thermal imaging to provide this same information in an easier to understand visual format.

@Richard,
of course, it's logic (at least to me) that adding a windshirt increases your insulation value. But I just wanted to point out that my windshirt and rain shell are sized to be worn with just a baselayer underneath and perhaps a thin insulation layer and that there is no way that they can be layered over my puffy..

However, I am more interested in the term 'relatively insignificant' and how high it is then (+ deviation) ? Is it e.g. 1%, less, more, … ? And is there any rising trend from low fill amount to high fill amount (even slightly)?

I find that an over sized windshirt also seems to breathe better when just layered over a baselayer, so i like them for warmer weather as well. I also like the dual aspect of layering over a puffy in the winter to boost insulation **as well** as protecting the puffy from any extra outside abrasion, snagging, and/or moisture.

One can find fairly light weight windshirts for fairly cheap sometimes. I bought a women's Champion polyester windshirt at Costco, brand new, and weighing in at 6 oz (size X large) for about 10 dollars. I then did a silicone treatment with silicone adhesive thinned with paint thinner and blended with a hand held blender. Repels water pretty well, though still a bit more breathable than a pre 2013 Houdini.

@Justin
And what is your normal size ?

Medium.

The X large Champions women's windshirt is just barely large enough to fit over a large men's NB Fugu jacket without compressing the down much, but it's a little short on the bottom (some of the NB jacket is exposed).

In men's size, i would say it's a large or large and a quarter extra (in this case, i would say ideally an XX large would fit better, but i also use it with a Stoic Hadron Anorak). It's not a athletic, Patagonia like cut though, so comparing it to say a Houdini is not very straight forward.

@Justin
I guess that works if that oversized windshell isn't too oversized and floppy when worn without a puffy.

Do you know the clo of the Mirage?

Living in the desert I get cold easily. I have been using a Fugu for a few years with good results, but it is somewhat heavy and has no hood and I am re-thinking my winter insulation.

I got this a while back from RN: "CLO for the MB Mirage was 3,51 with a thermo-neutral temp of 22 *F"

@Sean

Depends on how it's done. If the large baffles are filled properly, there shouldn't be much need for down control generally. Look at a Rab Neutrino…big bafffles but well stuffed.

Now on lighter fill weights, like a UL Parka or Ghost Whisperer, when you're dealing with under 4oz it makes sense as the jacket isn't that puffy to begin with. Thus extra baffles don't restrict loft. But look at how puffy a Rab microlight with 5oz of down is compared to a MB Alpine light (or the WM 4oz class jackets). They're much, much puffier and warmer.

Thanks!

Dustin, just clarifying, your saying the rab is loftier and warmer than the montbell and WM ?

jimmyb