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Mammut Aenergy SO Hybrid Review

Mammut Aenergy SO Hybrid
  • Protection from wind and snow
  • Thermal insulation
  • Breathability and ventilation
  • Wearability and freedom of movement
  • Design and functionality
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Highly breathable ski touring outfit consisting of jacket and pants. Both pieces have a hybrid construction: softshell in the areas most exposed to the weather and lightweight fleece with “waffle” structure in the areas where more breathability is required. The outfit ensures great comfort and freedom of movement both uphill and downhill. Ideal for spring outings, while if it is worn on particularly cold days it requires a few extra thermal layers.


  • Lightness
  • Breathability
  • Freedom of movement
  • Compressibility


  • Drawstring adjustment system for pants
  • Low thermal comfort on very cold days

The Mammut Aenergy SO Hybrid is a jacket designed for ski mountaineering and high-intensity mountain activities. As the name suggests it is a hybrid garment that very cleverly combines a lightweight but very high-performance softshell and a fleece with “waffle” structure.

Same goes for the Mammut Aenergy SO Hybrid pants, which with their elasticity provide maximum freedom of movement, both uphill and downhill.

High breathability performance and high lightness make this outfit ideal for days with not excessively cold temperatures and no precipitation.

Technical features of the Mammut Aenergy SO Hybrid

  • Main material: 92% polyamide + 8% spandex
  • Inserts: 88% polyester, 12% spandex
  • Technologies: SOFtech (softshell) + Stormfleece with waffle structure
  • Weight: jacket (size S) 350g, pants (size 48) 365g
  • Jacket: helmet-wearable hood, double-slider zipper, 2 front pockets, elastic cuffs
  • Pants: side ventilation zippers, 2 front pockets, anti-laminate Cordura reinforcements, adjustable elastic leg bottoms with zipper
  • Certifications: Bluesign, PFC Free, Fair Wear
  • Country of manufacture: VietnamI tested the Mammut Aenergy So Hybrid suit on all early-season tours, finding both winter conditions, with not very low temperatures (-5°C at the start), and typical late-season conditions (+3°C at the start).
  • Manufacturer link
testing the Mammut Aenergy so Hybrid

Test mode

I tested the Mammut Aenergy So Hybrid suit on all early-season tours, finding both winter conditions, with not very low temperatures (-5°C at the start), and typical late-season conditions (+3°C at the start).

skimo test

I used the Mammut Aenergy SO Hybrid jacket both as a middle layer and as the top layer, both uphill and downhill. Of course, I varied the rest of the clothing a lot depending on the weather I was facing from time to time.

Same with the pants: I wore them both with thermal underwear (of different heights) and without anything.

the back of the Mammut outfit

For most tours I found beautiful days, often with moderate to strong winds at the higher elevations. On one excursion we also encountered a light snowfall, for about an hour.

Mammut Aenergy SO Hybrid on-site test

Fabrics and materials

As the name of both garments implies, the construction is hybrid, specifically:

  • SOFtech: a lightweight bi-elastic softshell was used in the parts most exposed to the weather: specifically, in the front of the jacket, on the hood, shoulders and sleeves of the jacket. On the pants we find it on the entire front and in the calf area, combined with protective inserts made of anti-lamine cordura. Despite being a very light fabric, the wind protection is very effective. Even in high wind situations, despite being dressed light, I never had any problems or feeling of “drafts.” The same cannot be said about snow protection. I noticed this when bending down to put my skins away and, resting my knee on the snow for less than a minute, the fabric was wet. The degree of waterproofness is low, but sufficient to protect against light dry snowfall.
Softshell and fleece with cleverly combined "waffle" structure.
Softshell and fleece with cleverly combined “waffle” structure.
ski touring test
  • Stormfleece: softshell has been combined with an equally lightweight fleece with a honeycomb structure in the areas most prone to perspiration, such as the back, underarm area (starting from the hips down to the wrists) and the back of the thigh. This fabric increases the ability to evacuate sweat.
Detail of the "waffle" structure of the fleece
Detail of the “waffle” structure of the fleece
dropping in

Features of the Mammut Aenergy SO Hybrid Jacket

The main feature of the jacket is definitely the two large pockets in the chest area, easily accessible even with the harness on.

The size is sufficient to hold skins in case you want to keep them warm to reactivate the glue should you re-skin. Convenient drawstring sliders, easily handled even with gloves on.

mammut aenergy so chest pocket
Detail of the chest pocket with skins

The zipper closure is double-slider, which is useful in case you want to open the pelvis area slightly when climbing minimizing friction. Then you can close the jacket completely when descending, maximizing protection.

The zipper

The cuffs are made of highly elastic fabric and protect the wrists in windy weather. They feature a loop for threading the thumb, making them very comfortable.

Because of the high elasticity of the material, you can choose to wear heavy gloves over the cuffs or over light gloves.

The cuff with the thumb loop
The cuff with the thumb loop

The hood is very minimal, but once worn it offers the necessary protection from the wind. In case you want to wear a jacket over it, it does not bother or hinder movement.

The neck area remains well protected even with the hood unworn as the lapel is quite high.

the hood of the jacket

The only lack: of armpit zippers. However, given the lightness of the garment and the quality of the materials, the sweat issue was not a problem.

On a couple of tours, done at a brisk pace, in spring conditions, I never felt the unpleasant sensation of condensation or internal moisture.

Pants features

The main feature of the pants is comfort. The elasticity of the fabric enhances the freedom of movement allowing the most natural movements.

testing mammut aenergy so hybrid

In the front area we find two very generously sized pockets. If you decided to fill them, you would compromise freedom of movement; therefore, better not to take full advantage of the capacity.

On the side we find the ventilation zippers, also equipped with a drawstring and perfectly manageable with gloves on. I really appreciated the choice not to use nets; this way, the opening is extremely generous, global warming-proof.

ventilation zippers

In the boot area we find anti-laminate inserts made of cordura.

cordura insert

Minimal, but effective, silicone rubber band at the bottom that allows perfect boot coverage. I tested it with both 4-hook boots and less bulky 2-hook boots.

silicone rubber band

The only thing I personally did not like was the drawstring waist adjustment system combined with a button. While effective, I personally would have preferred a system with 2 side Velcro straps.

the closure of the band

Fit of the Mammut Aenergy SO Hybrid

The sizes of the jacket and pants use different scales: for the jacket I chose an S, and for the pants a 48.

I am 178cm tall and weigh 65kg. The jacket is perfect, it fits quite tight, while for the pants the 48 fits me a little big. I have to tighten the drawstring a lot, but as a length they are perfect.

fitting of mammut aenergy so hybrid

Recommended for

This is a ski mountaineering outfit clearly inspired by the fast and light philosophy. So, I recommend it to those who like to push uphill, grinding out many meters of elevation gain.

In this case, you will be able to use it even on colder days, possibly combining it with a good thermal underwear.

Conversely, if you’re a ski mountaineer who doesn’t mind performance, it can be a good choice for spring trips-or at any rate in mild weather-when the main problem is managing moisture from sweat and not defending against the cold.

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