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Marmot - Isotherm Hoody

posted May 6, 2014, 12:11 AM by GoOut Project   [ updated May 11, 2014, 2:29 PM ]

The award-winning Marmot Isotherm Hoody is one of the few insulating garments using Polartec® Alpha®, a highly breathable and quickly drying synthetic material developed by Polartec for the US soldiers. Of course, Go Out Project couldn't miss the chance to test this unique garment in its favorite lab: the Outdoor! Here, we report on the results of our tests... 

Technical Description

The core of the Isotherm Hoody is made of Polartec® Alpha®, a new synthetic insulation material that, unlike conventional synthetic insulations, is a knit material. The advantages of this material are its greater stability and durability, which allow to eliminate scrims or tightly woven fiber-proof lining fabrics. The outer material is a light 20 Denier Pertex Quantum© fabric. The lining uses the same material, except on areas that need more breathability (back, shoulders, armpits, and part of the hood), which are covered with a mesh of quickly drying material. Two stretchable softshell 
panels are placed o
n the shoulders to offer enhanced mobility. 
The Isotherm Hoody also features: 
  • Two hand warmer pockets and one chest pocket
  • Hood with single cord volume control
  • Elastic cuffs (no adjustments)
  • Elastic drawcord on the waist
Outer fabric: 20 Denier Pertex Quantum©
Insulating material: Polartec® Alpha®

Weight: 408 g (Size M)

Our Test 

We tested the Isotherm Hoody for more than six months for running, climbing, backcountry skiing, snowboarding,
splitboarding, hiking and mountain biking
. We've worn it in a relatively ample range of temperatures, mostly between -10 and +10 ºC. We have used it mostly in sunny conditions, but we had many chances to test it also in rainy/snowy days. We used it as an outer layer, wearing it directly on top of a baselayer or in combination with a light-weight fleece.

First Impressions
The Isotherm Hoody is a jacket that you can wear all day long! Very warm and comfy! Warm, but not too warm, protective, but not too bulky, greatly breathable, and very comfortable. The smooth and kind of "slippery" outer and inner fabrics are not bound to the filling material, so they form three layers that tend to slide on one another and on other clothes. This has the advantage of reducing the pull that normally tend to contrast your movements, but in some situations it may also be annoying, for example when carrying a backpack.
Some of the first comments from our testers: 
  • "I like it a lot!... I found it great for backcountry skiing and hiking. When skinning and hiking, it's warm enough and it lets the sweat on my back dry quickly."
  • It's comfy and warm enough! Very practical: it's like having a fleece and a windbreaker in a single garment.
  • It breaths very well, so I don't need to take it off as often as other jackets. 
  • "I find it very comfy! I'm wearing it almost everyday. The outer fabric is quite slippery though. The jacket often slides up on my back and my backpack slides on it!"
  • "At first I thought, ok another puffy... but soon I realised that, most of the time, I favoured it over my other insulators, simply because it's equally warm and comfortable, but much more breathable!" 
Lightness and Packability
With 400 g (in size M) the Isotherm Hoody can be considered a mid-weight insulating jacket. Despite its weight, the warmth it offers is not so extreme (more or less comparable to that of an average fleece). In terms of packability the Isotherm Hoody is not particularly impressive, especially if compared to analogous down filled jackets: the size M cannot be squeezed in less than 1L,
approximately the volume of an average fleece.

The outer fabric and the parts of the liner made of Pertex are very smooth and soft to the touch, but also quite "slippery". On the one hand, this guarantees good comfort and it eases the operations of putting on and taking off the jacket. It also enhances the freedom of movement, cause the jacket slides easily on any other clothes you are wearing. On the other hand, however, we noticed that this may also cause some problems: for example, the jacket often tends to slide up your back, therefore uncovering the lower part of the back and, when carrying a backpack, the lack of grip on you back causes the pack to slide more freely, therefore often compromising your whole stability and balance. The insulating material is relatively thin, which means that the warmth provided by this garment is not extremely high, which makes it better suited for high-intensity activities. The high collar, the wrapping elastic wrists bands, and the waist drawcord are all quite functional and effectively keep out any draft. The hood is not designed to be worn over a helmet, but it's very comfortable and warm enough. 

Fit & Cut
The fit is not very slim. Enough room is left for one, or even two, additional layers (for example a baselayer plus a thin fleece). The areas around the shoulders are roomy and, thanks also to the stretchable softshell panels, this guarantees an excellent freedom of movementThe relatively loose fit on the trunk and the construction that uses three separated layers not bound to one another, also favours a slight degree of air circulation, which is of great advantage in high-intensity activities. In all the high-speed sports we tested (ski/snowboard and mountain bike), we often noticed a fluttering of the outer fabric, that may become quite annoying at very high speed

Weather Protection
Protection from wind is excellent
. The outer fabric and the synthetic filling material work very well together in shielding from cold wind. You will definitely appreciate this on the most exposed ridges up in the mountains. The outer fabric has no DWR coating, which, in case of strong rain, causes the soaking of water drops by the outer fabric. While light snow and rain are absolutely no problem, during the strongest down pours the water easily reaches the surface of the insulating layer, which then stops it. In fact, we never noticed water penetrating all the way in. Definitely not the best garment to wear under the rain, but at least the outer fabric and the insulating material dry very quickly. In case of intense rain, we suggest to wear an additional, light waterproof shell on top of it.

The relatively thin insulating layer is disconnected from both the outer fabric and the lining. This allows a certain degree of air circulation, which greatly favours breathability. But most importantly, the quickly drying mesh used on the most critical areas of the lining (large part of
the back, shoulders, and armpits) is very effective in keeping you dry and ventilated. Only in the most extreme uses, for example when hiking uphill at a high pace and with temperatures above 0 ºC, the breathability becomes insufficient.

The Pertex outer fabric is thin and light, but sufficiently resistant to wear and abrasion. Obviously, it's better to avoid contact with spiky objects, like trees, branches, bushes, rocks, and ski edges! The stretchable soft-shell panels on the shoulders, which are more subject to wear if you frequently carry a backpack, are made of a wear-resistant, good-quality material that withstood all our mistreatments. One of the greatest advantages of the Isotherm Hoody is certainly that it requires much less care and that it is more durable than a fleece or a down filled jacket. You can chuck it in your backpack and squeeze it as much as you can, it will always recover its original "puffiness" without being damaged.

The Isotherm Hoody effectively combines two layers in one: a highly breathable, quickly drying mid-weight insulating layer and a light windbreaker outer shell. This practically creates a unique garment that you can wear all the time without the need for frequent changes, which is obviously of great advantage, especially during backcountry skiing or splitboarding. The Isotherm Hoody
 is a relatively light an thin garment, therefore offering only "moderate insulation", but if combined with the right base layers, it is highly functional especially at moderately cold temperatures and for high intensity activities. It is a very good shelter against wind and you can use it even under light rain/snow. Probably for all these reasons this has been one of our favourite jackets for many outdoor activities during the past winter.

Our Verdict

We have put it to the test for months and we have to admit it: we loved the Isotherm Hoody! This unique garment can be considered as a valuable alternative to a classic fleece for all the outdoor activities that require intense physical effort. In fact, it is a truly
versatile garment
, that, if combined with the proper base-layers, can be used for a great variety of sports and outdoor activities. Its greatest advantages, compared to other insulating jackets, are its good breathability and the ample freedom of movement it offers. It also requires much less care and it is more durable than a fleece or other down filled garments. With the Isotherm Hoody you can't go wrong: you'll be warm, dry, protected, free, and fast out there!

+ Considerably more breathable than its competitors
+ Good freedom of movement
+ Very versatile, effectively combining two layers in one 

- Quite "slippery" outer fabric
- Some annoying fluttering in high-speed sports

 Lightness & Packability   7/10
 Comfort   8/10
 Fit & Cut   7/10
 Weather Protection   8/10
 Breathability   9/10
 Versatility   9/10
 Durability   8/10
 Total Score  8.0/10