Helly Hansen H2 Flow Jacket

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Manufacturer Description

Perhaps the most revolutionary mid layer since Helly Hansen invented the world´s first fleece in 1960. The H2 Flow men´s fleece jacket combines different materials in a unique construction for optimal performance. Lightweight, air flow system, mechanical ventilation and great insulation are key words.


  • 200g Polartec brushed fleece in main body with air pocket perforations
  • Air flow ventilation ports
  • Polyester ripstop shell outer fabric
  • Open mesh inside
  • Zippered hand warmer pockets
  • Drop tail hem
  • Full front zip with draft flap
  • Bottom hem bungee adjustments
  • Bluesign approved fabrics
  • Tested size Small
    • Weight – 398 g (14.0 oz)
    • Pit to pit – 53.2 cm (20.9 in)
    • Center back – 69.5 cm (27.4 in)
    • Sleeve length – 89.6 cm (35.3 in)
  • Retail – $180

YMMV Review

Helly Hansen has been an iconic outdoor brand starting back in 1877. First starting with water resistant jackets that revolutionized outdoor wear. Helly Hansen has also been at the forefront of the development of fleece and baselayers, both going back over 40 years. No days the gear is used by world-class sailors, skiers, and adventurers who spend their time between human will and nature’s forces. The gear is designed to handle weather at its worst and to keep on performing.

From the Front - Click to See Larger
From the Front – Click to See Larger

I have now tested several items from Helly Hansen, starting with their baselayers and all testing some of their training collection. I must say that the flow technology and this top in particular are very innovative. I want to thank Helly Hansen for providing me with a media sample to do this review.


The H2 Flow Jacket is very versatile. I used it both as a mid layer and outer layer depending on the conditions. Since it is so versatile I was able to use it cross country skiing, hiking, snowshoeing, and just around town. The H2 Flow is an insulated piece so I tended to grab it in cooler environments and used it actively in temperatures ranging from 20-55 degrees. It is not necessarily designed for use in the rain but I did get some rain and snow on some of my adventures.

From the Back - Click to See Larger
From the Back – Click to See Larger

Design ★★★½☆

Appearance (20%) ★★★½☆

Construction (35%) ★★★½☆

Materials (15%) ★★★★☆

Sustainability (10%) ★★★★☆

Weight (20%) ★★★☆☆

The Helly Hansen H2 Flow is an interesting jacket. The flow technology was developed a couple years ago in some of their insulated shell jackets. I particularly remember one jacket from my first Outdoor Retailer show. It had little down pods the size of half a grapefruit on the inside and a standard waterproof jacket shell. Since that design Helly Hansen has refined it to several jackets using that same idea. H2 Flow Technology stands for Hollow Heat Flow. This is a system that marries insulation both positive and negative spaces. The positive space is where insulation exists and the negative is where it does not. This approach to air flow regulation is proprietary to Helly Hansen. The unique combination of elements allows the wearer to regulate their temperature better. The H2 Flow Technology is 100% mechanical, it allows both small and large adjustments based on the users activity level. With the help of some of their athletes, Helly Hansen devised this system to address the needs of both staying warm but maintaining comfort even when active. Essentially a versatile jacket for a variety of activities.

When the wearer is warm

To accomplish this goal H2 Flow technology was created. Since heat is trapped in air pockets, Helly Hansen looked for designs where there were small air pockets located around the jacket. The design that was come up with looks a lot like Swiss cheese. The inner insulation layer has large holes located in it to trap warm air in. Another benefit of the holes is that it also makes the jacket weigh less. The H2 Flow Jacket has this fleece insulation in the chest and the back. These core areas are where it strategically makes sense for ultimate warmth. The fleece does not go down the arms, instead the jacket has lightweight polyester lining in the sleeves. It adds a bit of warm and comfort. Down the sides of the jacket there is no insulation at all. The inside of the body has a mesh lining that both protects the insulation while allowing plenty of breathability. The outer shell however is a ripstop polyester outer fabric that is wind and water resistant. The outer shell locks in heat inside the air pockets.

When the wearer is cold

Of course all these materials work together well from a warmth perspective so they had to add some features to help it breath. There are two air ventilation ports on the front of the jacket, one on each side. These zippered ports run nearly the length of the torso and are opened from the top down by very small zipper pulls. The zippered air ports let air easily circulate around your body by way of the holes in the insulation and mesh lining. This provides a fast and effective cooling effect that works more efficiently the more you move around. So in practice the jacket will breathe better the more active you are. The jacket also has a full length zipper that can be used for venting and the two hand warmer pockets are mesh lined so they can be opened a well for increased breathability. The pockets do have a nice lip at the opening so if they are opened or left open your items should not fall out.

Air Ports - Click to See Larger
Air Ports – Click to See Larger

The jacket has an adjustable hem with low profile adjustments on each hip to be able to adjust how tight the bottom of the jacket is. At the wrists the cuff are very basic. They are low profile elastic cuffs that keep it snug but also do not add any bulk . Since the H2 Flow is designed to be used as a mid layer or outer layer having low bulk cuffs helps it layer under a shell for those occasions. The jacket does not have a hood but does have a tall micro fleece lined collar for extra protection. One thing I like about this jacket is that it has been designed with a lot of technology but still has a clean and sharp package. All the vents and pockets are nearly invisible unless you are looking for them. This makes it not just a good active jacket but also great when out and about. I have seen several of the H2 Flow Jackets around town here in Bend this winter.

Another cool thing about the H2 Flow jacket is that the fabrics are bluesign approved. The basic idea behind the bluesign standard is to combine aspects of consumer safety, water and air emissions as well as occupational health in a single standard under the general objective of resource productivity. With its practical and solution-orientated approach, the bluesign standard creates transparency along the whole textile production chain without compromising functionality, quality or design. The bluesign standard considers all inputs, processes and technologies at their source. Through this so-called input stream management, chemical components containing critical substances can be handled in a safe way. The actual fabrics used may not be entirely sustainable but at least they have been created with the environment in mind.

Bottom Hem Adjuster - Click to See Larger
Bottom Hem Adjuster – Click to See Larger

Fit ★★★½☆

Adjustability (10%) ★★★☆☆

Arm Length (20%) ★★★½☆

Comfort (25%) ★★★★☆

Cuff (10%) ★★★☆☆

Ease of Movement (15%) ★★★☆☆

Torso Sizing (20%) ★★★½☆

Sizing is always an interesting thing. I have generally been a medium on most of my outdoor gear but have been noticing that sizes have been getting bigger, especially in US manufacturers. For those that do not know, I am 5’10” ½ and 160 pounds. I have a 38 inch chest and as of late have been buying small slim fit dress shirts as they actually do fit. That being said I do prefer to have a little room in my outdoor gear and never want to have a jacket with sleeves that are too short. Looking at the size chart by Helly Hansen, the size small has a chest of 36.5 – 39 inches and sleeve of 32.5 – 33.5 inches. These dimension left me in a quandary but I eventually decided to test a size small. I am not going to say that the jacket fit perfect but I was surprised that it fit as well as it did. Through the torso I figured that the small was going to be correct and it definitely was. I had enough room to layer over a baselayer with enough room that the jacket was not restrictive. The jacket has a regular fit according to Helly Hansen which essentially means it will be roomy in the cut. The jacket also has been designed with a slight drop tail hem for more back coverage.

The 3 inner fabrics - Click to See Larger
The 3 inner fabrics – Click to See Larger

My biggest worry with any jacket is always going to be the sleeve length. I really want the sleeves to be long enough and that is why I normally opt for a size medium. Well on the H2 Flow the sleeves were just long enough. If I reached out for something the sleeve might pull up just a hair but not enough to be annoying or really overly noticeable. I really would only be able to tell when I was trying to as most of the time I had no issues. I do not think that I have long arms so if you do they may be a bit on the short side. The lining in the arms is not the same as n the torso. Instead of a mesh with fleece behind it, the arms are lining with a micro fleece for a balance of warmth and comfort. This micro fleece is thin so it does not impede movement while still being soft and comfortable to the skin.

In the torso the jacket has a different feel. The mesh has a comfortable feel against the skin and you cannot tell there are holes in the fleece unless you slide you hand over the top of them. The only place that has a different feel is under the arms and down the sides where there is no insulation. The seams in this area are a little bit more noticeable both to the touch and when moving around. They never caused any discomfort or problems, I could just tell from time to time that they were there. I do not think anyone will have any issues with them. I never wore this jacket straight against the skin as I always had a baselayer or t-shirt on. I did however test the H2 Flow with a pack several times and had no discomfort even with the weight on my back.

At the wrist the H2 Flow uses a basic elastic trim that keeps the wrists snug and low profile. For me there was a little room around my wrist but not enough to consider it loose. I generally like to have some adjustment there but since this is a mid layer I can understand why they did not include that. Adding wrist cuff adjusters always adds to the bulk around the wrists and would make layering more difficult. As is the wrist is nice and low profile and was able to layer under my shell jackets with ease. At the bottom hem Helly Hansen has added an adjustable bungee cord that can be adjusted on either side. This allows you to cinch up the bottom when needed and keep snow and cold air from coming up from below. I found that in my testing I varied the fit al little depending on what activity I was doing. While this is not a highly technical addition, it is nice to have.

Low profile wrist - Click to See Larger
Low profile wrist – Click to See Larger

Performance ★★★½☆

Breathability (20%) ★★★★☆

Durability (10%) ★★★☆☆

Packability (10%) ★★★☆☆

Pockets (10%) ★★½☆☆

Versatility (15%) ★★★★☆

Warmth (20%) ★★★★☆

Weather Resistance (15%) ★★★½☆

What really set the H2 Jacket apart is its performance. The design is different and in my testing I was pleasantly surprised at how well it worked. There are often designs that are different than the norm but often they do not live up to the billing. I must say I was impressed by this jacket. The two air port vents on the front do a good job of regulating temperature. You can open them only part way for just a little breathability or all the way to get quite a bit of air movement. These vents with the holes in the internal insulation and a breathable mesh lining allow air to circulate just as Helly Hansen says it does. The jacket is more breathable the more active you are but this still works when still. It also still works to some extent with a backpack on but of course is better without one. You can also use the hand pockets to add some extra breathability if necessary. I generally did not use these as I had stuff in them but it is possible.

H2 Flow Technology - Click to See Larger
H2 Flow Technology – Click to See Larger

What I liked about the jacket is that it was its versatility. It was plenty warm when fully closed up. The outer shell blocks wind and light rain and even though there is holes in the insulation, they trap the warm air like they are supposed to. I used the jacket cross country skiing on a day that was in the 20s and was plenty warm in my core. With the sun I warmed up too much in certain sections and was able to regulate this heat with the air ports just like stated. Warmth wise I would consider it equal to a heavy fleece or lightweight insulated jacket. It blocks some weather but it is more breathable and temperature regulating than either of those mentioned. The jacket felt equally at home around town, skiing, hiking, and snowshoeing. A very versatile jacket.

Since the outer shell is made of ripstop polyester I have not had any issues with durability. It has been able to stand up to everything thus far. I would worry about the holes in the insulation but they have been protected on the inside by a mesh liner and that setup has been plenty for keeping the fleece protected. The H2 Flow only has two hand warmer pockets. That is one of the drawbacks for me as I like to have a chest pocket, either inside or out. This is where I like to store a Smartphone or GPS and not having one is a bit disappointing. The H2 Flow comes in at 14 oz which is lighter than a typical fleece but slightly heavier than some of the lightest insulated jackets. You do get a jacket that is much more versatile. The holes in the insulation also allow the jacket to be packed down small when hiking but like the weight, insulated jackets are able to pack down slightly smaller.

Overall ★★★★☆

Overall, I think Helly Hansen has done a great job with this jacket. The H2 Flow has some intriguing technology that actually works. Now there is a jacket that not only insulates but can be worn when active as it can dump the excess heat. Yes, there will still be times when you will need to either open up the front zip or even take it off but this will not be nearly as common as it is with other midlayers. I had a couple small negatives on the jacket in regards to pockets, packability, and weight but these were all minor things. I would not let any of these keep you from checking out this jacket unless they are your primary concern in a mid layer. The H2 Flow Jacket is a big winner in my book and one of my favorites. Sizing is true to size so take a look at the sizing chart and buy appropriately. The Helly Hansen H2 Flow Jacket retails for $180, which is on par with other midlayers of this warmth. Not much has quite the same versatility which is what sets this apart. As always, your mileage may vary.


  • Excellent breathability
  • Very versatile with air ports
  • Jacket has a clean appearance
  • Swiss cheese holes in the insulation works
  • Fits according to the sizing chart
  • Comfortable


  • No chest pocket
  • Packs up slightly larger than a puffy
  • Weighs slightly more than a puffy

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About the Author

I am an avid runner, cyclist, swimmer, hiker, climber, skier and many other activities that would make this list too long. I started Your Mileage May Vary Reviews in Early 2011 to combine two of my passions: sports and gear.

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