A New Paradigm for Understanding Garment Warmth

[Richard Nisley]

Yesterday I read some BPL posts answering questions about low budget garment outfitting for ultralight backpacking. It struck me how confusing all the options must be for a newbie. I then thought that warmth relative to Polartec fleece products might be the easiest way for people to understand their options without having to wade through technical jargon or vague environmental descriptions. This post is an attempt to see if this different approach makes sense to people.

If I say, “It is the same warmth as a Polartec 300”, everyone can understand.

If I say, “The Patagonia Polarguard Delta Pullover’s intrinsic clo value is 1.06 and its total clo value is .509, the experts understand, but the laymen are confused.

If I say, “The Patagonia Polarguard Delta Pullover kept me warm at 30F around camp, the laymen think they understand but the experts know that the information is of little practical value to either the laymen or the expert. Without knowing the wind rate, the reporting persons BMR, the MET rates and durations for their camp activities, and the change in the reporting persons core temperature at the beginning and the end of the camp activities it is impossible to ascertain the insulation value of the garment they are reviewing.

I created the following chart to be Montbell centric. The other garments I listed are common alternatives to comparable Montbell garments.

Trying to determine the warmth of a garment by just measuring its loft is a measure of futility. For example, the Patagonia Polarguard Delta Pullover and a Wild Things Primaloft One sweater both have a loft of .6”. The Wild Things sweater is more than 27% warmer. The Montbell Alpine jacket has 2” of loft and box baffles yet the New Balance Fugu, which uses sewn through construction, and only has 1.5” loft is 64% warmer. The Montbell Alpine Jacket and the Montbell Permafrost Parka both use box baffles and have 2” of loft; the Permafrost Parka is 41% warmer. A Polartec 300 jacket has .25”loft and a Patagonia Polarguard Delta pullover has .6” loft and yet their insulation value is the same. The only two cases in which the loft is relevant is if you want to compare synthetic garments using the same insulation type and quilting. The other case is base layer garments; their warmth is correlated with their thickness.

In January 2010 there were a number of posts asking for clarification of the specific fabrics I tested. I answered these questions in separate forum posts. In addition, I updated my chart to includes fabric weight information. Version 2 of the chart is as follows:

In January 2011 there was a request to add information regarding how wind would affect the insulation value of each garment. I answered this related question is new post at http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=42263&skip_to_post=359270#359270

[Robert Blean]

Can you tell us more about what makes for a better rating?

When a manufacturer comes out with a "new and improved" version next year, how do we know whether or not it still occupies the same place in your table? And if not, then where it belongs?

How do I determine where a garment not in your table fits in?

— MV

[Dennis Park]

Richard,

By any chance, would you know where Mountain Hardware's Compressor men's jacket would fit on your chart?

Oops, forgot to mention 2007 model.

[Ashley Brown]

F%$king brilliant Richard! (excuse my French)

I remember coming up against this exact problem when I started looking at lightweight clothing alternatives. You're right… for most traditional backpackers fleece is the gold-standard for comparison, and almost everyone knows how warm it is.

The funny thing is though… I recall asking you in a thread about the MB alpine light down jacket and you said it had a similar clo value to 300 weight fleece (you even made me a graph!). I remember being surprised, because my 300 weight fleece isn't that amazingly warm. But this bar graph sets it all straight! It agrees very much with my own qualitative judgements of warmth now that I know some of the garments. And, indeed, the MB light alpine jacket is *much* warmer than 300 weight fleece!

Anyway, excellent work. This is going to be very useful for newbies. Actually, it'll be useful for just about anyone! (including me!)

Cheers, A

[Ashley Brown]

The MB UL thermawrap doesn't fare too well in comparison to the UL down inner does it?

I suspect a lot of the perceived insulation value of the thermawrap is because of its ability to cut wind.

But why is the parka so much more insulating than the jacket? I thought there would normally only be less than 10% difference (in non-hypothermic situations).

[Misfit Mystic]

Hi Ashley, the Thermawrap Parka uses a heavier insulation than the jacket, a fair bit heavier in fact. The Montbell site quotes the jacket as using 50g/m2 Exceloft, while the parka is listed as 80g/m2. My understanding was that the parka used the heavier insulation through the torso while using the lighter insulation in the arms and hood, however Montbell does not infer this distinction in their specs or product description.

[Ashley Brown]

Thanks Scott, that makes a lot of sense.

The other thing that surprised me was the fact that a cotton t-shirt has similar warmth to 100 weight fleece. Sounds a bit odd to me.

[Roger Caffin]

Yeah, well, I have some T-shirts which are made from very thick cotton knit, and some which would compete with a silk nightie.

Of course, the values are for DRY cotton. Wet fabrics – very different.

Cheers

[Huzefa @ Blue Bolt Gear]

>The Montbell Alpine jacket has 2” of loft and box baffles yet the New Balance Fugu, which uses sewn through construction, and only has 1.5” loft is 64% warmer.

>Richard Nisley
( richard295 – M)

Locale:
San Francisco Bay Area
New Balance Fugu on 05/26/2007 20:31:03 MDT Reply Report Post Print

I have a few things to add to Paul's recommendation to purchase the Fugu including the warmth of the jacket, the fabrics used, and the looks. The New Balance Fugu claimed 4.6F increase in warmth based on the liner piqued my interest and so I did some tests. First, this is what the liner looks like magnified:

:Liner

The tricot protection layer looks identical to the third layer used to protect eVENT and Gore-Tex membranes but, I have never seen the silver membrane below it before. Has anyone seen a similar liner before or know anything about this type of liner? For example, is it microporous or hydrophilic?

The Fugu tested significantly warmer than a Cabela's down jacket with the same single layer loft of ~1.5". It is very much warmer than a comparable loft down jacket than the modest 4.6F claim in their marketing hype. I suspect that this is primarily the result of the 850 down in the Fugu versus the 650 down in the Cabela’s. None the less, this unorthodox liner probably does make the incremental 4.6F contribution New Balance claimed.

My simple test was to IR measure the heat transmitted through the jacket in a 70F room and compare that with an identical loft down jacket and a jacket previously warmth tested by BPL. I used a regulated 135F (65F delta) heat source under each jacket and let each jacket acclimate for 1 hour. The mean 95F skin heat passing through the jackets in a typical 30F (65F delta) winter environment was simulated with this simple test. One other reference jacket I tested was the MEC Magma (1.1" Primaloft One). BPL previously tested this jacket as part of their Synthetic Belay Jacket tests.

MEC Magma (1.1" Primaloft One)……….86.4F
Cabelas (1.5" 650 Down)……….80.3F
New Balance Fugu (1.5" 850 Down + Radiant Liner)….77.1F

The less heat moving through the insulation and measurable on the outside surface, the better is the jacket’s insulation. To put the above numbers into another frame of reference, I tested my comparable weight Patagonia Micropuff pullover (.6" Polarguard Delta) and it yielded 90.1F of heat to the outside surface.

The material is quite windproof. A simple mouth breathability test yielded an undetectable air flow similar to the Epic Praetorian used in the Special Forces PCU Level 4 Windshirt.
___________

Does your test measure conductive heat loss? You seem to have measured only IR heat loss.

Considering average loft is 70% of max or 1.05", this give the garment and incredible clo of approx. 6.18/inch… Did you take the IR test measure at the point of highest loft? Then the effective clo value would be 70% or 4.326. If not I wonder why everybody at BPL doesnt own one.

[Brad Rogers]

Thanks Richard! Your posts are some of the most informative on this site. This is a great tool for people picking insulation layers, too bad it can't be made a sticky post. I would love to see this updated regularly with other silmilar garments to see how they stack up.

I often talk about how much I have used and loved my Mont-Bell Thermawrap jacket (mine is a 2005 model). In the winter I often use it in conjugation with my Patagonia R1 pullover and rain coat. I guess that combo isn't as warm as I thought.

[Brad Rogers]

Is the Patagonia Polarguard Delta Pullover the previous version of the Micro Puff Pullover?

[Anonymous]

I think this is a very good chart and makes me want to take a third look at the Montbell UL Down Inner Jacket when I get the money instead of my Patagonia Micro Puff Pullover (Polargaurd Delta).

Is it possible you could put up the values for an Patagonia R2 and R4 or would you more correspond these to the Polartec 200 and 300 wt.s?

[William Puckett]

I absolutely LOVE the chart. Clear. Communicative. No advertising spin.

I, too, would like to see more comparisons. The more the better, imo!

And a big thank you, Richard, for your posts and the research behind them!

[Michael Davis]

Richard, I know that we are really heaping it on here, but take that as a show of respect for your always excellent, diligent research.

I have one more to add; that is how does Polartec's own "thermal pro" compare to Polartec's traditional fleece at the same fabric weight?

[Anonymous]

Richard,
Have you ever tested any of Under Armour's products? I am thinking specifically of their Cold Gear garments and their Compression garments. From a layman's perspective, I have been impressed, but would be very interested in your expert opinion, if you have worked with them.
Thanks much,
Tom

[David Mcevoy]

Richard thank you for the information; I for one, as a newbie UL backpacker, really appreciate it. I have a, probably very obvious, question: I own both the MB UL jkt and the Thermawrap Jkt – if I was to wear both at the same time would I just add the Iclo values, or is the value higher because of the insulation gap between both layers? Many thanks in advance,

Dave.

[Ashley Brown]

Dave, you can add the lclo values together to get a minimum lclo for the combo but yes, you get some extra insulation from the air gap too.

[Jonathon Rogers]

I see the old Polarguard Delta Micro Puff being used for calculations all of the time and wonder if the new Micro Puff jacket with Climashield Green insulation has the same clo.

Great work, Richard.

[Michael Febbo]

Maybe I have just not been following this conversation, but am I the only one who is amazed at the NB Fugu beating the Permafrost, a jacket designed for cold weather climbing?
Richard, how are these items tested? I would assume that the Permafrost would still be "real-world" warmer just due to the hood, but the Fugu is just amazing me given that it is 10 ounces lighter. I'm amazed- a 14 ounce jacket that is warmer than a belay parka… this is revolutionary to me.

[Roger Caffin]

Bear in mind that a jacket designed for use while climbing must have a pretty tough shell – and that spells weight.

Cheers

[Ashley Brown]

The difference between the permafrost and the Fugu is that the Permafrost has a much heavier shell. The Permafrost has "only" got 9 ounces of fill but weighs 25 oz. So presumably it is designed to be pretty bulletproof. The Fugu, on the other hand, weighs 13-14oz I think but has a much much lighter shell… so it's possible it may have more down in there or at least a similar amount.

But yes, pretty amazing! Goes to show you that sewn-thru baffles aren't that great in comparison to having extra down.

Read an earlier post from Richard about the jacket (scroll down).

[Ashley Brown]

Snap, Roger. Gee I hate it when people say things more succinctly than me and post it while I'm still composing!! ;-)

[Michael Febbo]

You're right, the materials will add weight- though the Permafrost should be very warm for its weight given its welded box construction, 9 ounces of 800 fill down, and rather thin shell (15 and 30 denier). It's actually not tough enough for me, which is one reason I have stayed away from it. Still, it appears that the radiant liner of the Fugu is of greater value- warmth wise- than more down fill…

[Huzefa @ Blue Bolt Gear]

This means neither Alpine Jacket nor Permafrost Parka are filled at optimum down density.

[Adrian B]

This is a fantastic graph. Suprising to me is how high powerstretch is up there, I wish it had less elastine (12%) which (I believe) makes it slower drying. It's also a bit fragile (the mountain hardware Zip top I had was anyway).

[Author]

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