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Reviews > Clothing > Jackets and Vests > Helly Hansen H2 Flow Jacket > Test Report by Derek Hansen


Photo courtesy Helly Hansen

Helly Hansen — H2 Flow Jacket

Test Series by Derek Hansen


NameDerek Hansen
Height5' 10" (1.78 m)
Weight170 lb (77 kg)
Email Address pix-obfuscated
City, State, CountryFlagstaff, Arizona, USA


I am a lightweight backpacker with a typical overnight pack weight of 15 lb (7 kg) and a multi-day weight of 20 lb (9 kg), each of which includes food and water. I prefer backpacking with a hammock as part of my sleep system.


Manufacturer Helly Hansen, Norway
Year of Manufacture 2013, made in China
Manufacturer’s Website
Listed Features
  • 200g Polartec brushed fleece in main body with air pocket perforations
  • Open mesh inside allows air to flow between the air pockets and the body, while protecting the construction during intense activities
  • Zippers in front allows mechanical ventilation and stimulation of air flow
  • Polyester shell outer fabric locks heat inside the air pockets
Manufacturer Recommendations
  • Wash 30 degrees
  • No bleach
  • No tumble dry
  • No ironing
  • No dry clean
  • No fabric softener
  • Wash dark colors separately
  • Close the zipper before laundering
Specifications What They Say What I Say
Weight N/A 14.2 oz (403 g)
Colors Cobalt Blue; Black
Size Tested Men's Medium (Other Sizes Available: S, L, XL and 2XL)


16 Apr 2013



Helly Hansen describes the H2 Flow Jacket as a lightweight mid-layer. The "H2" stands for "Heat and Hollow" based on the insulation that is punched with circular holes meant to trap heat in little hollow pockets. The outer shell is made from polyester. Helly Hansen makes no claims about the shell being either water resistant or waterproof, although many reviews claim the shell is water repellant.


The inner lining of the jacket is made from a polyester mesh. The middle insulation layer is clearly visible through the mesh, is made from 200g Polartec brushed fleece. The fleece, as mentioned earlier, is riddled with holes and looks like Swiss cheese. The fleece is only present on the front and back of the jacket and is missing in the sleeves and along the sides of the jacket between the armpit and hip.


There are two zippered pockets on the front of the jacket. Between the zippered pockets and the main zipper are two zippered vents. These vents zip vertically and open up an area for mechanical ventilation, similar to armpit zippers.


The bottom hem has an elastic drawstring that is adjusted on either side with a cord lock and pull system. The cuff is slightly elastic.


The sleeves have two layers: the outer shell and an inner soft fabric, with an almost flannel feel. This same soft lining is present around the collar.


This is the most interesting mid layer I've ever worn. On one hand, it is an excellent wind breaker or shell, yet the insulation and air pockets lean it toward an insulating layer. I'm still musing about how best to use this jacket in my activities to see how well it performs.


It is currently the windy season where I live and so I've been able to really test the H2 Flow Jacket in sustained 40 MPH (64 km/h) winds with gusts up to 60 MPH (97 km/h). With all the zippers closed, the jacket performs well as a wind breaker shell. The wind didn't penetrate the jacket, but I could feel some heat loss along the sides where there was no insulation, and along my arms. However, when moving about, I didn't notice much heat loss.

Opening the front zipper vents I could feel an immediate difference. Wind rushed immediately into the jacket and I had to close them quickly -- it was a big change. I'm looking forward to testing the vents at different activity levels to see how well they work.

The sewing and manufacturing are top-notch. Everything about this jacket feels high quality and I see no flaws anywhere.

The jacket doesn't pack very small. I can get it about the size of a cantaloupe, but that's about it.

One night, I took the jacket out as I worked on some hammock stands in my backyard. The temperature was 40°F (4°C). Within a few minutes I was feeling cool, especially in my arms and sides. Even while moving about, the jacket wasn't warm enough to be comfortable and I had to get a warmer layer. There was only a little wind.

Based on the product description and sizing chart, I picked the medium size. Usually for jackets I size up to large, but the medium fits great, loose enough for a light base layer, such as a 200-weight fleece or Merino wool shirt. The jacket slips easily under my other insulating layers, so it will work fine as a mid layer.

The fit is great and the jacket feels good to the touch. The only thing that is bothering me is the collar. When zipping up around my neck, the zipper tightens up and pushes against my larynx. I hope this loosens up over time, otherwise I won't be keen on zipping up the mock-turtle neck.

The two sleeve layers are not sewn through, so they slide against each other. This is most noticeable when I put the jacket on and my watch or hand catches the inner layer and tugs against it as I push my hand through.


An interesting mid layer: part wind shell, part insulation. I'm worried about the tight collar zip and the lack of insulation around the arms and sides.

PRO—Very warm when active. Great wind shell. Great ventilation

CON—Minimal insulation layer. No insulation on arms or sides.


9 Jul 2013


I've used the Flow jacket on three backpacking trips and a few day hikes and camping trips, totaling 13 days and more than 30 miles of backpacking.

Apr 17: Old Caves Crater, Arizona. I did a few day hikes around the cinder hills, each about 3 mi (16 km) long. The elevation change was 1,400 ft (427 m). The wind was very strong, gusting at times to 40 MPH (64 km/h), with temperatures around 40°F (4°C).

May 17-18: Walker Lake, north of Kachina Peaks. Elevation was 8,000 ft (2,438 m) with overnight temperatures in the 50s°F (10°C). I did about two miles (3 km) of day hiking.

Jun 4-8: Whitehorse Lake and Camp Raymond Boy Scout Reserve. I spent a week out with my family doing some car camping for various summer camp events. Conditions were dry and hot with temperatures in the lower 90s°F (30s°C). I completed a 2 mi (3 km) day hike and accumulated about 5 mi (8 km) of hiking on various events.

Jun 14-15: Oak Grove Trail, Southern Utah. I went on a backpacking trip with my nephews and mom in the Pine Valley Mountain Wilderness in the Dixie National Forest up the Oak Grove Trail. Elevation was around 8,000 ft (2,440 m) and the temperatures ranged from 90s°F (30s°C) to 50°F (10°C). This was a short 4 mi (6.5 km) trip.

Jun 21-22: Sycamore Rim Trail. I completed a 12.4 mi (20 km) backpacking trip with the troop. Elevation change was 1,400 ft (427 m). The daytime temperatures remained a mild 85°F (30°C), but overnight it dropped to a chilly 35°F (2°C).

Jul 2-3: Mount Timpanogos, Utah. I completed a 14 mi (22.5 km) backpacking trip with my son and nephew up and down the mountain. Elevation gain was 4,389 ft (1,338 m) up, and 4,900 ft (1,494 m) down. During the day it was a cool 85°F (30°C), and overnight it maintained a comfortable 50°F (10°C) at 10,000 ft (3,050 m).



Appearance - The jacket has maintained a pristine look, in spite of some rugged use. While on the appropriately-named Oak Grove Trail, we had to wade through chest-high brambles of oak and other scrub plants that grabbed and pulled at the jacket. I feared a few times that I had snagged or ripped the jacket, but thankfully it has held up fine. The zippers have performed well, although I remain cautious. I've only snagged the main front zipper twice, but I easily unjammed it.

Weather Resistance - I've only been in a light sprinkle with the jacket and it has been fine. Where the Flow really performs is in the wind, where I hardly notice the gusts when I'm moving. However, when I'm stationary, I can feel heat loss on my arms and sides where the jacket lacks insulation.


Comfort/Warmth - As the temperatures have warmed, I've only been able to tolerate the jacket in the early morning and late evening. I find that this jacket works best between 40 and 50°F (5 to 10°C), otherwise I get too hot. The jacket is comfortable to my skin and it feels great to wear, but its temperature comfort range leaves me wanting more. For me, it has a small window of optimal use. It's not warm enough for me while hanging at camp when temperatures are below 45°F (7°C) and I find I need additional insulation.

The neck remains a problem for me. When fully zipped, the jacket is tight against my neck and it bothers me over time.

When I'm hiking, the front chest vents haven't really done much for me. In order to properly vent, I need to remove the jacket. On the Sycamore Rim, I wore the jacket in the morning to stay warm (my only insulation layer) and after 30 minutes of hiking, I was sweating and had to remove the jacket.

Weight/Packing - Where I'm really disappointed with this jacket is its weight and bulk. In combination with the warmth range, the heavier weight and bulk compared with down jackets makes it hard to recommend this jacket when I'm backpacking. In fact, in order to use this for "evening wear," I need to bring along an extra insulation layer so I feel comfortable at night or the cool mornings. On the Sycamore Rim Trail, I was absolutely freezing in the morning with the jacket and I had to move around a lot to get warmed up. I wasn't expecting the big dip in temperature, and all I brought was the Flow. Had I brought a down jacket, it wouldn't have been a problem.

Ironically, when I backpacked up Timp, I brought both the Flow and a down jacket, playing it safe as I expected cool temps at elevation. I never had to use the down jacket, and the warmer temps were just perfect for the Flow. However, the Flow took up much more room than the down jacket in my pack and weighs nearly twice as much.

The synthetic insulation in the Flow doesn't compress as much as down-filled, as expected, so this jacket takes up more room in my pack for less insulating ability.


I've really had a difficult time finding a "sweet spot" where I would use this jacket backpacking. I believe in layering, but as a mid-layer, it doesn't have enough insulation, or insulating power, to justify the added weight and bulk that could be achieved with other options, such as a down jacket and a wind shell. Even a fleece or merino wool mid-layer would be more modular with other layers than the Flow in my opinion.

That said, the Flow works well at staying warm (possibly too hot) while moving about in moderate effort.

PRO—Great wear, good fit, and look.

CON—Heavy and bulky compared with down jackets and not as warm. Not great for warmth with low activity, such as around camp in the evening.


5 Sep 2013


I've worn the pants on a few overnight trips and a few day hikes, totaling more than 80 miles (129 km) of backpacking.

Jul 15-20: Arizona Trail, Arizona. I took our Boy Scout troop on a 50-mile (80 km) backpacking trip (final mileage was closer to 55 mi (86 km) along the Arizona Trail. We had about 1,000 ft (305 m) of elevation gain and very moderate temperatures, thanks to the monsoons.

July 31-Aug 4: Lake Powell, Arizona. Family vacation on the lake. The temperatures were around 90°F (32°C).

Aug 9-10: West Clear Creek, Arizona. I backpacked a short 8 mi (13 km) down into West Clear Creek for an overnight hammock camp. The temperature was a pleasant 70°F (21°C).

Aug 23-24: Marshall Lake, Arizona. The elevation was 6,500 ft (2,000 m). During the night, the temperature dropped into the mid-50s °F (10 °C) and we had drizzly rain all weekend.


Over the summer, the jacket has been a little too much to wear during the day, but I did use it at night when I wore it to bed to supplement my sleeping system and then in the morning to stave off the chill. I typically could only wear it for about an hour before it warmed up too much.

I have no complaints about the jacket overall. The material and hardware have all held up well and perform as well as when I first received the jacket.

My feelings about the weight and "when to pack" the jacket are still up in the air. For an active layer, I find that I heat up too quickly and the venting options aren't enough to cool me down.

I guess I would characterize the jacket as working "okay" for me, but I had a hard time trying to find the best "niche" for when I would use it on a regular basis. It's just such a unique blend of materials and construction that it doesn't currently work for my own established layering system and outdoor usage, particularly backpacking. It has been a constant struggle between what I wanted the jacket to do and what the jacket could give back.


This is a beautifully styled jacket that I'm still trying to figure out. I don't think I'll take it out backpacking again, when comparing this to other insulation and wind protection options available to me, but I'll continue to use it around town.

PRO—Great wear and durability.

CON—Nothing new.

I would like to thank Helly Hansen and for providing me with the opportunity to test this product.

Read more gear reviews by Derek Hansen

Reviews > Clothing > Jackets and Vests > Helly Hansen H2 Flow Jacket > Test Report by Derek Hansen

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