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A New Paradigm for Understanding Garment Warmth
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Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 12:29:10 MST Print View

Tom K,

Great question regarding the breathability trade off of increased down density. I don't know the answer but, I will try and check to see if there is any published research that answers that question.

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Re: Re: Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 12:39:59 MST Print View

That would be much appreciated by the proud owner of a WM Ultralight with 2 oz of overfill. I think it probably was a good idea, but this question has gnawed away at me off and on over the years. I haven't had it out on trips over 11 days and those were in the Sierra in late Sept-Oct, where it worked fine. Winter trips are another question entirely and the results might well be different if I miscalculated the tradeoff.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 12:50:05 MST Print View


I appreciate your experience based contributions to this topic. I suspect we have more common ground in our insulation views than our respective posts might lead others to believe. The same insulation types and similar densities will indeed thickness correlate with the warmth of garment. It is the exceptions in down density, down fill power, or differences in synthetic insulation types where anomalies occur. I am sure that there are one or more people in the forum audience who will peer-review at least some of the anomalies I pointed out. As these additional peer-review tests are published, we will both gain additional insights that will allow us to achieve more common ground.

Chris Townsend
(Christownsend) - MLife

Locale: Cairngorms National Park
A New Paradigm for Understanding Garment Warmth on 02/24/2009 13:12:56 MST Print View

Richard, I'm sure we have much in common and I appreciate your posts and information. I am trying to correlate your information with my experience. The down density issue particularly interests me as I have not come across this before.

With regard to down fill power and synthetic insulation I have come across many anomalies, especially with the latter. And not just between different synthetics but between apparently identical bags with identical insulation. Synthetics are not uniform. Overall I've found synthetic bags - and I've tested dozens over the years - to be over-rated, some scandalously so. I'm a warm sleeper but have yet to find a synthetic bag that keeps me warm at the claimed temperature rating. With many down bags I am warm below the lower temperature rating. I have raised this with synthetic bag makes occasionally - replies I've been given include "we know serious users don't use synthetics so the temperature ratings are just to make the bag sound good", "we know the bag isn't warm at the claimed temperature rating but our competitors claim the same for similar bags so we can't change it" and "we have no idea what the actual rating is - we just copied what other companies said about similar bags".

Lynn Tramper
(retropump) - F

Locale: The Antipodes of La Coruna
Re: Re: Re: RE: A New Paradigm for Understanding Garment Warmth on 02/24/2009 13:33:41 MST Print View

>If someone in the Bay area has a Nunatak Skaha to loan for a test, I will also add that info.

If no one volunteers, I might consider mailing one to you. The postage costs would be outweighed by the knowledge gained for the BPL collective...

Michael Davis
(mad777) - F

Locale: South Florida
Re: A New Paradigm for Understanding Garment Warmth on 03/03/2009 06:14:29 MST Print View


Thanks once again for this superlative post that will lead us to many excellent purchases for our gear closets and to the "gear swap" forum to make room for those purchases :-)

I think you covered some of this in your response concerning Under Armor base layers but I'll ask anyway. I use merino wool base layers but, I have some very heavy 320 and 390 weight for winter use. They feel very warm and cozy to me, but I suspect, some of that is due to the other properties (wicking, etc) that you mentioned concerning base layers in general.

My question is, at these stout thicknesses of wool, can you determine their insulation properties, as I have been wearing them as insulation, not as a base layer, although I think they function as both?

Even though these wool garments are heavy, I have preferred them for hiking over my Micropuff or my Montbell Alpine Down as I don't view these as durable enough with their thin shells, or synthetic insulation crushed by the pack, or down absorbing all my sweat. I have limited these "puffy" garments to rest stops and camp or to augment my sleeping bag. But, should these wool garments show that they don't really insulate well, maybe I should reconsider my choices.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: A New Paradigm for Understanding Garment Warmth on 03/03/2009 07:39:45 MST Print View


In summary, don’t change a thing.

The heavier Merino wool base layers, as well as the Polartec Power Dry and Power Stretch fabrics, serve a hybrid role. They address the base layer function plus adding insulation beyond what is required for a base layer. The complex weaves and bi-component nature of the aforementioned Polartec products make simple estimations difficult. On the other hand, the thicker Merino wool base layer’s insulation value can be accurately estimated. Measure the uncompressed thickness in inches and then multiply this value by “4 clo/inch” to determine where they are positioned in the insulation graph.

If you are thermo neutral (not uncomfortably cold or sweating) when hiking in your heavier Merino wool garments that is an excellent combo base layer/insulation solution. When you are hiking, you will be typically average in the range of 7 METS. You will only require additional dedicated insulation when your MET level drops significantly. While hiking, you will subconsciously vary your pace in an attempt to stay thermal neutral (not cold or hot). For the same effective temperature that you were comfortable hiking, you will require ~7/1.5=4.7x more insulation when doing camp chores. That activity is typically the province of the dedicated insulation garments.

Edited by richard295 on 03/03/2009 07:41:11 MST.

Michael Davis
(mad777) - F

Locale: South Florida
Re: A New Paradigm for Understanding Garment Warmth on 03/03/2009 10:47:29 MST Print View

Thanks once again Richard!
Now I feel both physically and academically warm in my wool!

Edited by mad777 on 03/16/2009 20:44:50 MDT.

f sol
(europeclimber) - F
Re: Re: Re: A New Paradigm for Understanding Garment Warmth on 03/14/2009 11:11:35 MDT Print View


As for your Montbell figures,i am a little confused by a former post published by you Nov 28th 2008 (not so long ago)from which i deduce that the MB Alpine jacket CLo would be around 2-2.2 , ie quite lower that what is shown in your nice graph. pls see below


own a Mountain Hardware Sub Zero with sewn through construction. It weighs 27 oz in size medium. This is primarily because the external fabric is 55 denier, the liner is 30 denier, and the insulation is 650 fill down. Mountain Hardware doesn’t publish the down fill weight or the clo value of the jacket. Also there is no other independent source that has published the clo value for this jacket. I tested it in my lab and it yielded an intrinsic clo value of 4.477. To put that number in perspective it is more than double the warmth of the Mont-bell Alpine jacket which is Mont-bell’s warmest light weight down jacket. The MB Alpine was also tested by me. The MB Alpine uses 800 fill and box baffles. The MH Sub Zero is an excellent jacket if you require that level of warmth in combination with extreme durability. Equivalent warmth in a jacket using 800+ fill down and lighter fabrics will require ~ 9 oz of 800+ fill

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: Re: Re: A New Paradigm for Understanding Garment Warmth on 03/15/2009 23:40:24 MDT Print View


The most recent chart I published showed the intrinsic clo for the MB Alpine jacket to be 3.769. The Mountain Hardware Sub Zero tested in the same battery of tests yielded and intrinsic clo of 4.521 versus 4.477 in the earlier November test. This makes the Mountain Hardware Sub Zero approximately 20% warmer than the MB Alpine not 200% warmer as was stated in my November 28, 2008 post. I made a mistake in the November post. Thank you for a great job of consistency checking. I have now corrected the November 28, 2008 post to reflect the correct warmth relationship.

The updated November 28, 2008 post is located at

dav rt
(dr150) - F
Questions about SubZero Jackets & Primaloft on 03/20/2009 00:21:08 MDT Print View


MH quotes 261g of down in a size L in the Sub Zero jacket and 364g in a size L of the HOODED Sub Zero jacket.

Since they don't offer hood/jacket breakdowns, how much of that 103g difference is placed in the hood in a logical opinion?

Also....are these SubZero jackets warmer than the Phantom (197g size L x 800)?....

I also wonder if a 200g Primaloft jacket could compete with these jackets for warmth.....I keep reading about people using these jackets in 0F degree weather YMMV of course.....

Edited by dr150 on 03/20/2009 00:39:34 MDT.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Questions about SubZero Jackets & Primaloft on 03/20/2009 23:04:04 MDT Print View


To recap, my laboratory tests showed that the MH Sub Zero jacket with 9.2 oz of 650 fill down was approximately 20% warmer than the MB Alpine jacket with 6 oz of 800 fill down.

The down, normally allocated to a hood, is in proportion to the average body surface area increase. A jacket covers approximately 48% of your body surface. A hood covers approximately 7% of your body surface area. 7/48 = 15% anticipated increase in the amount of uniform coverage down oz by adding a hood. The fill values you quoted are approximately 28% higher for the MH Sub Zero hooded jacket. This infers that additional insulation was also added to the jacket. In other words, 300.15g of down, not 364g is required to add a hood with equal warmth to the rest of the jacket.

The MH Phantom uses approximately 9 oz of 800 fill and so it will be warmer than the MH Sub Zero jacket using 261 g (9.2 oz) of 650 fill.

200g Primaloft One insulation equals 6 oz/yd2 and 1” of loft. The theoretical clo value, based on the insulation manufacturer’s spec would be 5.040 clo. The laboratory tests I conducted on two different manufactures garments, using this insulation, yielded about 2.52 clo. By contrast, the MH Sub Zero tested 4.521.

Your reading about people using 200g Primaloft One jackets in 0F weather means nothing unless you at least know there average MET rate for the rating period in addition to the their core temperatures before and after the rating period. For example this winter I spent a full day out in -30F wind chill temps wearing only a Power Stretch hoody and hooded wind shirt and was comfortable. Although the preceding sentence is true it is of no value to your ability to gauge the warmth of a Power Stretch hoody. Only if you knew I was that my average MET rate for the day was 7 could you approximate the relative warmth of what I was wearing.

dav rt
(dr150) - F
Primaloft Question on 03/21/2009 01:34:06 MDT Print View

Thanks for your very insightful response. Good info.


Does "laminating" (instead of quilting) Primaloft Sport substantially improve the warmth, waterproofness and longevity of this material (per a mfgrs. statements)?...

BTW, isn't 650 x 261g fill (MH SubZero) warmer than 800 x 197g (MH Phantom) (MH quoted me 7 ounces instead of ~9oz.)?...

Edited by dr150 on 03/21/2009 01:36:47 MDT.

Huzefa Siamwala
(huzefa) - M
Re: Primaloft Question on 03/21/2009 02:05:47 MDT Print View

I am not sure there is much advantage in laminating Sport. Sport has minimal quilting requirement so seam stabilization may be sufficient depending on the pattern. Seam will be there even in a garment made of laminated sport. Difference in warmth will be minimal.

Lamination is done to liner.. so waterproofness will depend on shell fabric, zippers and whether it is seam sealed.

Longevity? not sure. synthetic insulation do not have much of a life anyways.

Richard, did you get my PM?

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Primaloft Question on 03/21/2009 08:49:30 MDT Print View


You are correct on the fill amount for the Phantom. I was going by memeory. I looked at my files this morning and the Phantom was listed at 197 g or 6.948 oz for size L.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: Primaloft Question on 03/21/2009 08:51:30 MDT Print View


Good analysis!

I didn't receive your PM. Also I have some other PMs in the queue which I haven't had an opportunity to answer yet.

Tim F
(kneebyter) - MLife

Locale: the depths of Hiking Hell (Iowa)
re: new paradigm on 03/21/2009 11:17:20 MDT Print View


Not to belabor this point, but I also thank you for giving of your time and knowledge to help fellow backpackers understand these issues. You have taught so many of us not just the what (garment X is *relatively* warmer than garment Y), but the why (clo values, MET for different activities, BSA coverages). I think your posts let people understand this stuff at whatever level they want to or are able to. One can take away an understanding of how to calculate some of these values oneself given the right information, or simply look at one of your easily understood graphics for a quick comparison. Also fully explaining the right and wrong of long held axioms (such as loft vs down density) has changed completely how I look at some choices.

I also wanted to let you know that if you have not done any testing on the BPL Cocoon 60 jackets I would be happy to ship mine to you, and pay for return postage. Might be best to wait until June when I won't be using it. Let me know if you are interested.

Andrew Shapira
(northwesterner) - MLife

Locale: Pacific Northwest
Request to add weight to the table on 09/12/2010 10:42:14 MDT Print View

Nice table, Richard. I appreciate your putting that together. Is there any chance that you could add the weight of each jacket in the table, say, in parentheses after the jacket name? That'd help make the tradeoffs even clearer.

jim jessop
(LuckyJim) - F
Primaloft v Polarguard Question on 09/20/2010 16:04:27 MDT Print View

I was wondering where a light-weight primaloft one hoodie like the Patagonia nano-puff would compare in the table versus a BMW Cocoon UL 60 hoodie? Any thoughts?

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Primaloft v Polarguard Question on 09/20/2010 17:55:43 MDT Print View


The WT jacket in the chart is comprised of 2 layers of 60 g/m2 PL1. Other PL1 jacket's clo value can be estimated by simple extrapolation. The Pat Nano Puff uses 1 60 g/m2 layer and so it would test with approximately 1/2 the iclo value.

The Cocoon used 1.8 oz/yd2 Polargaurd Delta and the Patagonia Micropuff used 2.7 oz/yd Polargaurd Delta. Again a simple extrapolation can be used to estimate the Cocoon's iclo value from what I published for the Micropuff.

Edited by richard295 on 09/20/2010 18:29:16 MDT.