Review of the OMM Core Hoodie integrated into a lightweight mountain clothing system

My experience of how the OMM Core Hoodie fares as one layer of a 3 layer adjustable, flexible and lightweight mountain clothing option

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Review of the OMM Core Hoodie integrated into a lightweight mountain clothing system

Two things have recently got me fixated on my own ability to travel lightweight in the mountains. No, it's not speed either!

The first is that I am nearing 70 years of age. How has time flown, eh? Anyway, my time is limited in the mountains, so to make the most of every single opportunity I get, it will help to reduce pack weight.

The second is that in July I am attempting the Alta Via 2 trail in the Italian Dolomites. A distance of 150 kilometres with over 10,000 meters of ascent/descent. It's a hut to hut tour so no need for camping equipment. With passages of via ferrata along the way, helmets, harnesses and lanyard must also be carried. The aim is for a pack weight of under 7kg + water. I need every bit of assistance I can, so I have started to look at my own clothing system.

Some of my "usual" and "go-to" mountain garments have been with me for years. I trust them implicitly and know what they can do. But, beacuise they have been with me for years, they are heavy. In particular I am thinking about the various fleeces I have accumulated. Even the latest "lightweight" ones weigh almost 500 grams. A short while ago I started bringing new, modern clothing systems into my life.

The 3 layer system that will be the mainstay of my travels in the Dolomites at the moment contains:

  1. Base layer - RAB Mens Force T (110 grams)
  2. Mid Layer - OMM Core Hoodie - the basis for this review (115 grams)
  3. Outer Layer - Patagonia Houdini Windshirt (105 grams)

Total 330 grams!

The OMM Core Hoodie uses PrimaLoft ACTIVE as an ultra-light insulating fabric. There are other fabrics around that I have yet to test. For instance good reports have been posted about Polartec Alpha Direct which is found in the Macpac Nitro Fleece Pullover and also garments from Senchi Designs.

PrimaLoft ACTIVE ultra-light insulating fabric PrimaLoft® ACTIVE ultra-light insulating fabric

I could only get the black version in my size but other more exciting colours exist for the fashion orientated! Talking of sizing, the fit is tight, so unless you want it tight to the skin I would go for a size larger.

NB. The above system is also supplemented by a rain protection garment not subject to this review.

BASE - RAB Mens Force T

From the manufacturer Link

"Simple, lightweight, and fast-drying the Force short sleeve tee is slim fitting and comfy. Perfect for hiking, climbing and mountain running, the Force Tee is soft next to skin and quick-wicking, built with Motiv™ fabric. With an odour control finish, the Force tee is ideal for multi-day adventures. It has dropped shoulder seams for comfort with a backpack and is ideal as a baselayer"

MID - OMM Core Hoodie

From the manufacturer Link

"A new concept in active insulation, the OMM Core Range is made entirely from PrimaLoft® ACTIVE ultra-light insulating fabric. Built from a synthetic plume woven through a knitted mesh, Core offers the warmth of a fleece but at less-than half the weight. Paired with a shell, the Core is an incredibly effective insulator but thanks to near-total air permeability, the lightest breeze can take away that heat. This allows you to keep your Core layer on even when you have warmed up and you can thermoregulate by removing/unzipping your shell. A true valley to summit piece. Core works wet or dry with incredible wicking properties to ensure you won’t stay wet for long."

Blue and Black OMM Core Hoodie I like this colour - Blue and Black OMM Core Hoodie

OUTER - Patagonia Houdini Windshirt

Manufacturer Link

"An ultralight jacket designed to help you stay warm in cool windy weather. It’s not waterproof or insulated but provides a windproof layer to prevent the cold air from stripping away the heat trapped in your baselayer or mid-layer clothing"

Core Hoodie hood up with Patagonia Houdini Windshirt Core Hoodie hood up with Patagonia Houdini Windshirt

How does the OMM Core Hoodie perform as part of an integrated mountain clothing system?

The test came appropriately on a cold day with mountain temperatures of 10 degrees centigrade and with 20 kilometer per hour winds. Within 10 minutes of leaving the start point, my fellow hikers all wore plenty of warm clothing including fleeces, jackets, warm hats, gloves and one person even had a down jacket.

My own 3 layer system coped well with the initial mountain cold and wind, although both the hood of the OMM and the Houdini needed to be raised over my head. Thermal gloves were required too.

Later in the day the sun broke through the cloud and Andalucia returned to it's January norm. Sun, blue skies and warmth.

Overall, a good initial test. 5 hours, 500m ascent and 13 kilometers later, with a good mixture of cold, wind, warmth and calm, what had I learnt?

Too cold? I could try the following:

  1. Raise OMM hood
  2. Raise Houdini hood
  3. Put on thermal gloves
  4. Last resort - add another insulating layer

Too hot? I could try the following:

  1. Take off thermal gloves
  2. Pull down Houdini hood
  3. Pull down OMM hood
  4. Open Houdini front zipper
  5. Roll up Houdini sleeves
  6. Last resort - take off Houdini jacket
  7. Last resort - take off OMM

Bear in mind, this is an "active" layering system. It starts to click into gear and becomes effective when you start moving. My own experience is that you don't need to be working too hard either, just a gentle plod will balance temperatures and make you feel comfortable.

Being an active layering system, on top of the mountain, in the cloud eating my sandwiches, I needed an extra insulating layer over the top. Until I started moving again, that is.

extra insulating layer over the top When stopped at the top of a windy hill, I needed extra insulating layer over the top. My wife, in the orange/red Core Hoodie seemed to cope perfectly fine!

My adopted, ultra lightweight, 3-layer system coped very well with a wide range of weather conditions. Only slight tweaking was required throughout the day, although as we descended, got out of the wind, and the temperatures rose above 20C, I found a base layer alone was sufficient.

After a day in the hills, there was no dampness on the base layer nor the OMM mid-layer. Some slight dampness on the Houdini jacket was felt, where the backpack had snuggled against my back, but that was not uncomfortable and dried out within minutes in the air. I suppose if I had lowered the zip earlier then any air ingress would have wicked that moisture away.

The OMM Core Hoodie is featherlite and works very well as a mid layer. It feels superb against the skin and wicks away any moisture. You hardly know you're wearing it. Any breeze though and it goes right through. This is good news as it means you have lots of small temperature tweaks and adjustments you can make. I gather it can be worn as a base layer alone, although I haven't tried it yet.

My only reservation about the OMM Core Hoodie is it's durability. It is just so light and flimsy. I kept it well away from thorny bushes, which adorn Spain's hiking trails in this region, as I suspect tears could happen rather easily.


The OMM Core Hoodie may be designed for mountain athletes, trail runners and fastpackers who sole aim to travel light and fast in the hills. Let me tell you, it also works for slow, ageing plodders with dodgy knees who can't carry much weight on their backs!

A recommended piece of kit!

OMM Core Hoodie rear view with hood up OMM Core Hoodie rear view with hood up

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