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MontBell U.L Down Inner vs. Patagonia Nano Puff?
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Nate Powell
(powell1nj) - F

Locale: North Carolina
MontBell U.L Down Inner vs. Patagonia Nano Puff? on 04/14/2010 22:16:26 MDT Print View

Anyone in a position to compare the warmth and functionality of these two jackets? Is one considerably warmer than the other? I'd love to hear about similar contenders that you think are sweet as well. Also, maybe this is a really dumb question but how do/would these types of UL garments fare against the occasional spark from a campfire? Methinks things may get ugly in that situation. I ask because I've been mostly a fleece user up to this point but I'd like to expand into the lighter/insulated jacket world. I do, however, enjoy the occasional campfire which has kept me away from dropping $$$ on these types of garments for fear of a meltdown. Thanks in advance for any info/insights.

Dan Durston
(dandydan) - F

Jkts on 04/14/2010 22:22:44 MDT Print View

Yup these jackets won't do so well against flying camp fire embers. I got a small hole in my Montbell UL Down Inner last week from one of these. Generally though I try to treat the Montbell as an 'inner' just like Montbell calls it. Around the campfire I normally wear my cheap windshirt which can then take the brunt of the abuse. As you can see from my avatar, I don't always adhere to this.

The Nano Puff might use slightly heavier face fabrics (30D nylon vs 15D?) but it's still not going to do so well against coals. You'd need pretty heavy nylon (70D or higher probably) to survive most flying coals.

The UL Down Inner seems to be a lot warmer than the Nano Puff. The Nano puff is pretty darn thin.

Edited by dandydan on 04/14/2010 22:23:54 MDT.

Robert Cowman
(rcowman) - F

Locale: Canadian Rockies
Nano puff on 04/14/2010 22:25:53 MDT Print View

Nano puff is warmer in my opinion. I have the UL parka and the nano puff and I find the Nano warmer when it isn't under a shell, if its windy the UL loses a lot of warmth through its seams.

Dan Durston
(dandydan) - F

lclo on 04/14/2010 23:31:40 MDT Print View

Based on Richard Nisley's excellent posts on this site, it seems the Iclo value of the UL Down Inner is ~1.8 and the Nano puff is ~0.5.

Nathaniel Lynn
(bc74sj) - F

Locale: Midwest
holes on 04/15/2010 13:49:40 MDT Print View

I have burned holes in my Columbia down, my Marmot Precip pants, Marmot Driclime windshirt, and columbia thin fleece all this year. Fire and UL just don't go good together, but I doubt I would camp as much if I didn't start fires. Price I have to pay for life I want to live.

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
down v. synthetic v. holes on 04/15/2010 15:32:27 MDT Print View

One advantage of synthetics like PL-One is that they don't rush out through every little hole like down does. Synthetic gets the nod, though as you point out fleece is best. Even though my pile hoody is 8 oz heavier than a synthetic puffy of the same warmth and feature set, its durability and quick-dryness means that I'm not likely to replace it soon. Too bad it takes up more room in my pack than my 20 degree synthetic quilt.

Ryan P. Murphy
(rmurphy) - M

Locale: Colorado
Re: down v. synthetic v. holes on 04/15/2010 19:49:02 MDT Print View

I agree with David that synthetics do better with sparks and flying embers because if you do burn a hole the insulation doesn't really noticeably leak out. I have a few holes here and there in my patagonia micropuff from sparks and it has never leaked.

I have tried both jackets on but never worn them for any considerable amount of time so take this as you will but I would guess that the nano puff is warmer. They both have vaguely similar lofts (which while loft is mostly irrelevant for synthetics, synthetics generally have a higher clo/inch than down meaning that on average when comparing a synthetic jacket and a down jacket with the same loft, the synthetic will be warmer although much heavier).

Also in regards to Dan's clo assessment I'll take his word for the clo of the u.l. inner down jacket as I don't know which of Richard's excellent posts he's referring to so I don't have the numbers in front of me. I think however that the clo of the nano puff is closer to 1.5. The nano puff uses 60g/m primaloft one, which if I remember correctly translates as 1.8oz/ sq yd (someone correct me if this is wrong) and the clo of primaloft one is 0.84 giving a clo of 1.5 for the nano puff.

Someone (Richard?) feel free to correct me if I made some glaring error here.

Dan Durston
(dandydan) - F

clo on 04/15/2010 21:05:15 MDT Print View

Here's the clo for the UL Down Inner (1.78):

I wasn't able to find a definate answer for nano puff, which is why I said that it 'seems' be 0.5. I based that on a post I found that used it's 0.3" loft to arrive at that value but it wasn't by Nisley and I'm not sure where it was, as I browsed a lot of threads yesterday to find it.

Edited by dandydan on 04/15/2010 21:06:21 MDT.

Ryan P. Murphy
(rmurphy) - M

Locale: Colorado
Re: clo on 04/15/2010 21:33:04 MDT Print View

For the nano puff to get the clo rating I believe you should multiply the synthetic insulation's "inherent" or "standard" clo value by the weight of the insulation (in this case 1.8 oz/sq yd or 60g/m) to get the "real" clo value of the article of clothing, quilt, whatever. As far as I know this is the standard way for determining clo for synthetics as the "standard" clo for a given material (i.e. primaloft one has a clo of 0.84) where as something like clo/given thickness is more useful for down products (really used for determining bulk?).

Sorry about the confusing terminology I'm just not sure how to refer to the different clos (material clo vs actual clo of the finished product) and I feel like Richard has them backwards in the linked thread. (I.E. I think the intrinsic clo should be the general rating for the material and the total clo the rating for the whole item accounting for various weights of insulation, how many layers of sid insulation, etc. In his post (see link) Richard refers to the intrinsic clo of polarguard delta as 1.06 and the total clo of the garment as .509 which seems to be backwards but it might just be that he chose random numbers because if I remember correctly polarguard delta had a clo rating of 0.7something.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: down v. synthetic v. holes on 04/15/2010 21:55:35 MDT Print View


I lab tested the MB UL Down Inner at 1.78 Iclo. The Pat Nano Puff wasn't tested. You are correct that the specs for Nano Puff should give it a 1.51 Iclo; so, theoretically the jackets should provide equivalent warmth.

Unfortunately all of the synthetic jackets I tested, from many different manufacturers, using many different types of synthetic insulations, tested significantly lower than their insulation specs. The closest synthetic insulation jacket to the Nano Puff, that I tested, was the MB Thermawrap jacket (50g/m2 Exceloft). It lab tested .48 Iclo versus its theoretical 1.26 Iclo.

Edited by richard295 on 04/15/2010 21:58:07 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: MontBell U.L Down Inner vs. Patagonia Nano Puff? on 04/15/2010 22:10:13 MDT Print View

I've used a MontBell regular Down Inner jacket for a couple of years without any holes. I just stay upwind from any fire.


Jaroslaw Kumorek
(Jarekk) - F
Synthetic fill Jackets and the real world on 04/20/2010 01:08:07 MDT Print View

Dear Richard,

I am a great fan of you scientific approach to the backpacking in general. Thanks to you mainly I was able to educate myself in many fields regarding clothing and sleeping systems.

I also admire you readiness to reply to many questions even those asked more than once.

I have read about synthetic clothing a lot. I personally own two synthetic jacket. I was greatly surprised to find out in one of your posts claim that synthetic gartment clo never comes close to the clo value of the bare insulating material. This is best shown in "A New Paradigm for Understanding Garment Warmth" thread, which also presents the data for actual tests performed by youself.

Since you mentioned above that you performed your test on various pieces of gartment and with different insulationg material, would be possible if you published here the results of your tests for synthetic jackets?

The theoretical iclo value next to value actually measured would be a great guideline for many who still consider synthetic as a down-killer.

Thank you


Rog Tallbloke
(tallbloke) - F

Re: MontBell U.L Down Inner vs. Patagonia Nano Puff? on 04/20/2010 01:19:50 MDT Print View

I have a Montbell UL down inner. It seems to be as warm as a synthetic I have that is twice it's weight (Highlander cheapie with polarguard insulation). The Montbell is VERY VULNERABLE to sparks. It won't burst nto flame but you'll put a hole in it very easily. I wear it under my walking shirt when I'm near a camp fire.

Edited by tallbloke on 04/20/2010 01:20:56 MDT.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Synthetic fill Jackets and the real world on 04/20/2010 13:08:27 MDT Print View


Per your request:


James Naphas
(naphas13) - MLife

Locale: SoCal
Re: Re: Synthetic fill Jackets and the real world on 04/20/2010 22:53:05 MDT Print View

As always, great stuff, Richard.

Walter Carrington
(Snowleopard) - M

Locale: Mass.
Re: Re: Synthetic fill Jackets and the real world on 04/21/2010 09:46:13 MDT Print View

Richard, this is valuable work.
Do you have any thoughts on why the down jackets do so much better than synthetics in test vs. theoretical?

The conventional wisdom is that synthetics are warmer than down when wet. Have you done anything to test or quantify this?

Thanks, Walter

Jaroslaw Kumorek
(Jarekk) - F
Re: Re: Synthetic fill Jackets and the real world on 04/21/2010 15:44:43 MDT Print View

Thank you Richard!

I am impressed again. Now, I will have a lot to think about.

I am still thinking of fleece, though. In your chart Polartec 300 rates iclo=0.92. Probably in case of the more modern Polartec High Loft this number could be a little higher especially that the weight has dropped and for Patagonia R2 Jacket it equals 419 g (14.8 oz), while Patagonia Micro Puff Jacket weighs 550 g (19.4 oz) but provides about 10% better iclo.
And what if I added a Patagonia Houdini over the R2? The weight of the two would still be below Micropuff's. How much better would the total iclo of both be? Have you ever tested such a combination?

Thank you once more for readiness to share such great information with us.


Bill Fornshell
(bfornshell) - MLife

Locale: Southern Texas
Re: Re: Synthetic fill Jackets and the real world- Richard? on 04/21/2010 16:10:20 MDT Print View


Could you run a test on just a piece of an insulated garment. If you had just a piece of insulation with a shell material sewn to the front and back could you get a reading that would be close to a real garment test result?

What I am getting at is, if I sewed say Pertex Quantum as the front and back shell material and had PL - 1 as the insulation could you get a good test from that? Then do the same for several of the popular insulations and compare them.

I could sew together several different synthetic insulations I have on hand using PT-Q and Cuben Fiber and send them to you. How big a sample would be necessary?

Would such a test have any meaning?

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Synthetics therorectial insulation value versus my Iclo tests on 04/22/2010 15:22:20 MDT Print View


My WILD GUESS is that idealized samples and the cherry picking from different test methods accounts for the clothing insulation specification variance.

Wet is like the color grey. Near the saturated (black) end of the spectrum, synthetics are warmer than down. On the light gray end of the spectrum (very high relative humidity and cold temperatures) down insulation, used in clothing, performs comparably.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: Re: Synthetic fill Jackets and the real world on 04/22/2010 15:31:48 MDT Print View


Light insulation in combination with a windshirt or shell can average an addition of ~.6 do to the Iclo values of insulation plus the windshirt. See my post at