Bill -

Clo is the insulation provided. Clo is normally used for clothing insulation because it is relatively easy for people to understand that 1 clo is the warmth provided by a mens business suit.





1 MET is the amount of calories you are burning and consequently the amount of heat you are generating when you are in a prone rest position. All other activities are represented as multiples of this calorie expenditure / heat expenditure. You are only comfortable when the heat generated is the heat lost.



Thanks for helping me understand that I should have started by defining these terms.

Edited by richard295 on 09/06/2007 08:42:42 MDT.

Richard - I can tell you why I don't pay much attention to this level of detail, especially with regards to clothing...

Primarily, there is a limit to how much obsessing about gear that I want to do. The CLO value of base layers as an example goes beyond that threshold. It's the same reason that I have no aspiration to be super duper uber light - I don't have the patience for it.

I want a flexible clothing system that meets a wide range of conditions with a reasonably small gear closet. My (possible mis-)perception is that you take a more honed approach and (my guess is)have invested more to create options that meet more specific environmental conditions.

You ask the engineering question - what is the optimal solution? I ask - what do I have that will get 'er done? You conclude that hoody plus windshirt is an optimal solution for hiking in dry cool to cold weather. I concluded a long while ago that a baselayer and windshirt works great most of the time when it's chilly. Not having a hoody and owning a few wool caps - I conclude "good enough". Different process - similar solution.

It's not that I don't learn from you and others who plan in greater detail... I just don't invest as much in finding the "best" solution.

Edited by jackfl on 09/06/2007 09:03:29 MDT.

Jaiden - MET values are available at for almost all activities. Just pick a number from this data base

MET Database

I answered your clo calculation question in a prior post answering another person with a similar question.

The average clo per inch for insulations is 4. 800+ down fill is 6.562 clo per inch if it is fully fluffed. You need to use clo/inch and not clo/oz for the Iclu clo calculation. If you don't know what the actual clo per inch is, just use the average which is 4 (3.906 to be more exact).

Edited by richard295 on 09/06/2007 09:12:32 MDT.

Richard,

Thanks for the reply, I'm pretty sure I follow it, but if you'd stick with me I want to paraphrase it back to you to be sure I understand.

1) From a purely material point of view, 320 g/m2 Merino is approximately equal to R1 material when it comes to material Iclu clo calculations.
1 alt) An alternate reading of your sentence would be that 390 g/m2 = R1 (aka Shak = R1)... so from a materials point of view 320 g/m2 ~ 88% R1

2) ISO specifies a standard hoody BSA% for use in the clo calculations. These calculations Smartwool hoody conforms to this pretty well, as the SW Hoody fits much like a standard ISO Hoody. However because of superior design the Shak and R1 Hoody outperform ISO Hoody predictions (one could consider this to be an increase in effective BSA%).

3)If the Nomad fits better / closer than a standard street hoody, treating it as a Smartwool hoody would be 'conservative'. If it's more loose-fitting around the neck (as is the SW Hoody), treating it as a SW would be 'equivalent'.
3 note) By my recollection the SW Hoody is ~ 320 g/m as well. If this is not the case (aka the nomad fabric is lighter than the SW Hoody fabric), then I would replace 'conservative' with 'equivalent' and 'equivalent' with 'optimistic'.

Of note using the ISO Formula the SW Hoody comes to about a 0.50 Iclu?
Also, so clarifications on the ISO Hoody Forumla:
A) Which is the correct placement of parenthesis.
Iclu = (.43 X 10)-2Acov + (1.4 Hfab x Acov)
Iclu = .43 X (10-2Acov) + (1.4 Hfab x Acov)
B) "Acov is the body area percentage as a whole number and Hfab is the thickness in meters" what you mean is that for Acov, is should use MY body's total surface area (found from the BMI calculator page) x the ISO '54.5% BSA for a hoody', the Hfab I can measure with rulers.

EDIT - I just realized that those numbers presume a certain body size (total surface area) do they not? Though of course, if I simply wanted to estimate it, as long as I adjust the Clo needed for my BMR compared to the average male BMR thatn I'll have a pretty good 'starting point' for estimating my ensemble needs.

Edited by jdmitch on 09/06/2007 10:59:45 MDT.

Richard, anybody that knows me..knows I am full of bull much of the time and joke around alot. Some of my posts are of the brutal honesty type that do not necessarily go over well with others.

I honestly had not heard of clo until you had mentioned it in the past. I guess I'm like Jack Flanagan who doesn't worry much about that part. Not that it doesn't have meaning, and it does, because it allows someone to calculate how much insulation the gear provides. So, it is important.

Why do they not care? Maybe only because those numbers are not provided easily up front on purchase for the average person to educate themselves on the meaning so they can compare the values with other gear they own or are shopping for.

As for suggestions on how to better present the information? I don't see how anybody could present it better than you have. I do appreciate when someone like you takes an interest in an area that many do not understand. Keep up the educating posts.

I'm still really lost here, as none of my calculations ever come out to match yours. I'm sure I'm misunderstanding something. It seems that the more I dig into this, the harder it becomes. I hope you don't take any offense if I've misquoted something.

As I own a Shak, I've tried to duplicate your numbers for that.

Attempt 1)
Per an older post, wool is clo of .08 per oz
.08 clo/oz* 17.5oz *.545 = .763
(.545= 54.5% body coverage in a hoodie, 17.5 being my measured weight on a crappy and probably incorrect scale)
This one is wrong, you already told me not to use this way

Attempt 2)
"If you don't know what the actual clo per inch is, just use the average which is 4 (3.906 to be more exact)."
"The short answer is the Ibex Shak is 390 g/m2 and measured .080 loft"

.080 * 4 *.545 = .174... much lower than the numbers quoted for the shak elsewhere.

Attempt 3)
"Iclu = .43 X (10-2Acov) + (1.4 Hfab x Acov)
Acov is the body area percentage as a whole number and Hfab is the thickness in meters"

Iclu = .43 * (10-2(.545)) + (1.4 (.080*.0.0254) x (.545))
this gives 3.83, and a negative value if I express Acov as a "whole number" (54) instead of a decimal. Both clearly very wrong.

I'm sorry I'm so dense on this matter, but it seems that the information on the subject is scattered in many places and is sometimes contradictory. (I'm not putting this on you, I mean the ISO, EN, etc.)

Perhaps we can add a column to the gear guide for the actual clo of the item? At least a list of common items all in one place would be nice. I think a lot of us have identical or similar gear.

Thanks again for all your efforts in attempting to educate my concrete filled head.

I would like to add on to Jaiden's suggestion. Repackaging all the information that is available in this post (and a few related ones) would go a long way in making this topic clearer. I think Richard has done an outstanding job in presenting the information, but I think some of the clarity has been lost due to it being jumbled around in the forum posts. I think this would be an excellent topic for an article.

Edited by pstetz on 09/06/2007 13:28:09 MDT.

Would be nice if the clarified version would turn into an article for general consumption.

It's weird how all of Richard's charts go in strait lines, (meaning they should be easy to understand)???

I wonder how many mets I'm burning while you're trying to figure out your clothing and met rate to see what you need for a certain temperature and then trying to figure out what articles I need to put on when I stop thinking about it, aahh, I'm getting cold.

Coming soon

THE COMPLETE IDIOTS GUIDE TO CLO!!!

I have always thought technical hoodies made very versatile pieces. I use thin merino for base layers (Ibex) but prefer light fleece for my general purpose midlayer for the weight savings (the merino pieces like the Shak tend to be heavier).

1) Does anyone know how the Patagonia R1 Hoody (98% polyester 2% spandex) would compare for warmth with a Powerstretch Hoody, which has nylon mixed in to aid with moisture management and a little wind resistance? I have an old R1 top, not the hoody, and the material is a little denser and heavier than a polartec powerstretch zip top. The material used in my R1 from several years ago is the same mix as the material Patagonia uses in the R1 today. I find that R1 zip top is a little warmer and heavier than my powerstretch zip top, but less wind resistant (though the powerstretch top is not highly wind resistant and I always wear my Patagonia Houdini wind jacket with it in windy conditions.

Note that there are different types and thicknesses of powerstretch with different percentages of polyester and nylon and stretch material. Generally, more polyester is warmer while more nylon moves moisture better and offers more wind resistance.

2) Can anyone recommend a merino hoody that offers the same warmth for weight in the same weight range (around 9-10 ounces) as the Patagonia R1 Hoody?

A good light hoody is an item I'd love to add to my kit.

Thanks for the very informative post.

The only way you'll find a merino hoody near 9oz is with a woman's smartwool columbine hoody. I've worn my wife's and it's much lighter than my Men's medium Shadow hoody. I like it but it's not quite long enough to be perfect. These may be discontinued like the Shadow too.

This is an example of a Powerstretch Hoody of similar weight:

http://www.cloudveil.com/mens/pullovers/run+dont+walk+hoodie--CV06614/

Hi Chris,

How tight is that women's medium? I usually wear a men's Large (42 in chest) - I'm 6ft 185 lbs. Can't imagine squeezing into a top that fits my wife (she's a size 8 and also wears medium tops).

Also, how warm is it compared to the same weight in the R1 material?

well since I can get into a men's small (5'11" 150-155lbs) the women's medium isn't tight, just not quite as long as I'd like. In your case you'd have to find a women's XL at least and even that might not be big enough.

I can't compare it to an R1 yet, I've got one coming but it's not here yet. I ordered though a local store and they don't have their shipment yet.

Mountainwalker - Power Dry comes in three basic weights of light (3.1 oz/yd2), medium (5.1 oz/yd2), and heavy (6.3 oz/yd2). Power Stretch is available in 6.7 oz/yd2, 7.2 oz/yd2, and 7.3 oz/yd2. My Patagonia R1 uses a 6.5 oz /yd2 recycled version of the 6.3 oz/yd2 material and is .869 clo. My Ragged Mountain Power Stretch Hoody uses the 6.7 oz/yd2 and is .953 clo. In other words, my comparable weight Power Stretch is approximately 9.7% warmer than my Power Dry.

My R1 hoody uses 6.5 oz/yd2 Power Dry material. This material has an approximate clo per oz/yd2 of .138 as does the Power Stretch. Merino Wool averages a.084 clo/oz/ yd2. For the same warmth, any Merino wool garment will weigh .138 / .084 = 164% the weight of the R1 Power Dry or Power Stretch Hoodys. The Merino wool hoodys will also take much longer to dry if you get them wet.

Edited by richard295 on 09/10/2007 11:35:59 MDT.

1) To my knowledge, in addition to differences in thickness, there are differences in power stretch composition – does this matter for your considerations?

Power stretch is available in these and I’m sure other general Polartec as well as proprietary blends:
88% Polyester, 12% Spandex – example – Cloudveil power stretch hoody
64% polyester/24% nylon/12% spandex – REI women’s OXT power stretch tights
Fabric49% polyester/38% nylon/13% spandex – REI men’s power stretch tights
(I’m guessing more nylon is used in power stretch pants than in tops for durability)

I find a lot of variability in power stretch garments, which is why I wanted to know better how to compare them. For example, my wife has an REI power stretch hoody we found at a deep REI sale that is very light and well made, but very thin – which means power stretch must be made in a an even lighter formulation than 6.7 oz/yd2. By contrast, I have an old (maybe 8-10 years) Patagonia power stretch jacket which is a monster and indestructible – clearly uses A LOT of nylon and is thicker, more abrasion-resistant and wind-resistant than any other power stretch piece I have ever seen. So much so I don’t use it as a light piece but as an all around beater jacket and it looks good as new. It almost feels like putting on a light version of a neoprene jacket as the surface is so tough.

2) That said, I went back and tried them while clacking at my keyboard and indeed my Cloudveil power stretch zip top is warmer than my Patagonia R1 zip top, matching your general calculations. I’m just trying to find out if the Cloudveil hoody is the same composition.

3) Given the extra warmth offered by power stretch, given a choice, for your most flexible system, would you stick with the R1 Hoody or use a power stretch hoody? Would the extra warmth of the power stretch hoody make it less versatile?

4) My kit - I’ve always refined these basics because they are the most important elements of my kit. My wife and I take them everywhere and in more than a few situations the extra warmth and versatility made all the difference. The balaclava has come in super handy and at 2 oz we always take it. Personally I now use:

Base layer - Ibex light Pacifica l/s zip top (6.5 oz) - except in warmest times where I use lightest Patagonia silk capilene or a short sleeve Ibex zip top, though I find wool a bit too hot for the warmest most humid days)

Midlayer - Cloudveil Power stretch zip top (10 oz) with light Hind power stretch balaclava (2 oz) OR Old special edition thick R2 base later jacket (large weighs in at only 12 oz. with full zip) with the balaclava

Wind layer - Patagonia Houdini (3 oz.)

Insulation layer: Montbell hooded U.L. Thermawrap Parka (about 13 oz. size large) – the WARMEST synthetic garment for the weight I’ve ever owned.

EJ - 1) The Power Stretch composition and thickness both matter for your unique chosen application:

Style: 7416
The smooth, tightly constructed 160 denier Cordura nylon face provides superior abrasion and wind resistance. A semi-velour polyester back provides for good wicking, 3-season warmth, and next to skin comfort. Fabric has wicking/siphoning properties for moving moisture away from the body and a odor reducing treatment to inhibit the growth of odor-causing bacteria. Features four-way Lycra“ stretch for unrestricted movement. Ideal for climbing, mountain biking, and equestrian pursuits, where superior abrasion resistance, maximum freedom of movement, and clean profiles are desired.
7.2 oz/yd2
1.38 clo/oz yd2 (my estimate from averaging other Power Stretch version manikin tests)
Stretch W/H 80/80

Style: 7622
Double faced polyester velour with 4- way Lycra® stretch. The warmest Power Stretch® fabric. Lycra® blends give 4-way stretch for unrestricted movement. Fabric has moisture management properties and an odor reducing treatment for next to skin comfort. Ideal as a heavy, expedition weight underwear or for general cold weather layering.
7.3 oz/yd2
1.34 clo/oz yd2 (manikin test)
Stretch W/H 100/100

Style: 7767
A durable nylon/Lycra® face, with a non-pill, low pile polyester velour back. BiPolar construction allows the placement of different fibers front and back to handle varied conditions. The durable, smooth nylon face resists wind and abrasion, and allows for easy layering. The inner pile (back) has wicking/siphoning properties for quick drying and moving moisture away from the body, along with odor reducing protection from odor-causing bacteria. Lycra® blends give 4-way stretch for unrestricted movement. Ideal for cold weather first layer or next to skin applications such as winter running/cycling,/cross-country skiing tights, and accessories.
6.7 oz/yd2
1.42 clo/oz yd2 (manikin test)
Stretch W/H 60/60

This #7767 material is close to what is used in my Ragged Mountain Hoody. I prefer it because it has the lowest weight and the most warmth for the weight by not dealing with heavy abrasion protection. I use a wind shirt or hard shell to protect it against hard abrasion when required.

2) I own and use a Smartwool Merino hoody, an Ibex Shak Smartwool hoody, a Power Dry Patagonia R1 hoody, and a Power Stretch Ragged Mountain hoody. Reference my 9/5/07 17:15:50 chart post for this response. For backpacking MET levels from about 45F to 0F, I find the R1 Power Dry hoody / windshirt combination provides optimal variable thermal balance with the least amount of weight. This combination also provides the highest safety margin if they get wet and need to be expediently dried by hand wringing. A Power Stretch hoody would provide a comparable comfortable temperature range but in order to not sweat, its comfort range would start at a lower temperature or lower MET level.

Edited by richard295 on 09/10/2007 12:22:48 MDT.

Taking into account that each of us has a different temp. range for a given piece of clothing. What's the warmest temp you would use the Patagonia R1 Hoody in (Zipped down, sleeves up)?

Bill - If you are hiking relatively level ground at a moderate pace, it is comfortable from about 70F Down. If you are backpacking with a 21 - 42 lb pack through mountainous terrain, then is comfortable from about 45F down.

Edited by richard295 on 09/10/2007 12:32:23 MDT.