[Workman's Top Recommendation of the Year] Merinotech Active Insulation Review: Merino wool and graphene open up a new world of warm, breathable clothing for fall and winter activities (Developed in collaboration with Outdoor Gearzine)

Friday, October 10, 2025

Gear Review , Recommendations , Mid-Layer , Insulation , Workman , Sponsored

Written by Yasushi Hisatomi

For the past few years, I have been giving my input into Workman's development of mountaineering wear that can be used in real mountains, and this fall/winter season it's `` Active Insulation .''

The ideal clothing for autumn and winter mountain climbing, where you sweat profusely in the freezing cold, is "warm when standing still and cool when moving." Conventional thin fleece is cold when standing still, and down jackets are too hot when moving. Active Insulation , and is a product that requires particularly high functionality among mountain climbing wear. Who would have thought that the day would come when Workman would be making it?

It's been nine years since I first started working with Workman. That was in 2016, when Workman's outdoor line, FieldCore, was launched, and I feel particularly nostalgic when I think the insulation jacket I reviewed back then was quite simple and, frankly, a bit mediocre.

Workman's new product, Merinotech Active Insulation, is not only made with merino wool, as the name suggests, but also features a unique material that combines it with graphene, an advanced material that has been gaining attention in recent years. I've been using the prototype in the field this spring, so I'd like to share my review.

As always, Outdoor Gearzine has no involvement in product development other than providing input during the planning stage. We would also like to point out that the items worn in the reviews were provided by the manufacturers, and that no changes were made to the content of the reviews at the request of the manufacturers.

table of contents

Key Features of Workman Merinotech Active Insulation
Main Specifications and ratings
Detailed review of actual field use
Summary: The cost performance is simply too good to be true. This is an active mid-layer that you'll want to have in your wardrobe for the coming winter.
Learn more about and purchase Merinotech Active Insulation

Key Features of Workman Merinotech Active Insulation

The Workman Merinotech Active Insulation is a mid-layer (intermediate layer) that combines warmth, breathability, and freedom of movement, making it ideal for wearing over a base layer during cold-weather stop-and-go activities like mountain climbing. The main fabric is a unique blend of high-quality extra-fine merino wool, known for its natural temperature and moisture-regulating properties; polyester fiber blended with graphene, which combines excellent durability and thermal conductivity for warmth and cooling; and polyurethane, which combines high kickback for ease of movement and style. This unique blend provides a balanced combination of warmth, moisture wicking, breathability, stretch, antibacterial and odor-resistant properties, and UV protection. The slightly brushed lining provides instant warmth and comfort. The slightly higher collar, longer back length, and thumbholes on the cuffs are designed for extreme conditions. Zippered handwarmer pockets and a chest pocket provide easy access even when carrying a backpack are conveniently positioned for on-the-go use.

The lineup includes balaclava-style hooded jackets that fit the shape of your head, as well as hoodless jackets, vests, pullovers, climbing pants, neck warmers, balaclavas, and inner gloves, to suit a wide range of scenes, including autumn and winter outdoor activities and winter leisure activities, depending on your needs and preferences.

*Unless otherwise specified, the following is a review of the "hoodie" type in the lineup.

Merinotech Active insulation is available in a wide range of products, from hoodies and stand-collar jackets to pants, balaclavas and gloves.

Favorite points

Merino wool and graphene provide a good balance of warmth, temperature regulation, and moisture absorption/release
Comfortable fleece lining and three-dimensional cut for a comfortable fit
Excellent elasticity for easy movement and minimal deformation
Mountaineering details include ample pockets, a longer back hem, and sleeves with thumbholes
Amazingly low price
Wide range of options, including accessories

Interesting points

The weight is not that light
I'm concerned about the roughness of the lining seams.

Main Specifications and ratings

item	Workman Merinotech Active Insulation Hoodie
weight	430g (L size measured)
color	Khaki/black/orange
size	M / L / LL / 3L
material	Body: 75% polyester, 23% wool, 2% polyurethane (separate fabric: 100% polyester)
function	Front zipper pull with whistle Cuff thumb holes Hood with hook for switching between hoodie and stand-up collar Retroreflective print
pocket	Left and right zip hand warmer pockets Left chest zip pocket
Reference price (tax included)	2,900 yen
Outdoor Gearzine Review
Comfort	★★★★☆
Thermal insulation	★★★★☆
Ease of movement	★★★★★
It's not stuffy	★★★★☆
Functionality	★★★★☆
weight	★★★☆☆
Cost Performance	★★★★★★
Suitable scene	Clothing for a wide range of outdoor activities, such as hiking and skiing, when the cold weather really sets in Cold weather clothing for outdoor use during slightly chilly seasons

Detailed review of actual field use

Comfort and ease of movement: A knit with excellent stretch and excellent mobility, with a soft, comfortable fleece lining.

Although the name of this jacket is long and tough, as you'd expect from Workman, it's actually very comfortable to wear.

The fluffy, brushed lining feels smooth against the skin and keeps you warm from the moment you put it on. It's a soft, comfortable feel, like being wrapped in a blanket.

In addition to the softness of the fabric itself, the three-dimensional pattern allows for natural movement without hindering ease, and the excellent stretch with strong rebound keeps the silhouette while reducing tightness, so you will hardly feel any discomfort while moving around.

The back hem of the jacket is slightly longer to cover the waist. The sleeves and hem are piped with stretch material, providing a gentle fit while preventing cold air from entering. The standard fit is neither loose nor slim, but shows off the body lines, and the cuffs have thumbholes, making it easy to layer as a mid-layer. This aspect is clearly designed with mountain wear in mind, and it is made with a level of care that is hard to imagine given its price range (see photo below).

However, if I had to say something negative, it would be that the stitching isn't of the highest quality, with the lining seams being noticeably uneven and causing some discomfort. High-end, specialty brand jackets are designed with meticulous attention to even the unevenness of the seams to minimize movement and discomfort, but it would be asking too much of this jacket.

The actual weight is 366g (size L), which is within an acceptable range for an insulated jacket, but it is not that light compared to so-called high-end active insulation.

Performance: Comfort. The power of graphene evolves natural merino wool into high-tech active insulation.

As its name suggests, Merino Tech Active Insulation is not just a cold weather jacket, but is designed with the concept of being useful in cold, active situations, and nowhere is this aim more apparent than in the fabric used in this series. The fabric " MERINO TECH a combination high-quality merino wool (extra fine merino) and polyester mixed with the new high-performance material graphene

First merino wool is a natural, high-performance fiber that everyone is familiar with. High-quality merino wool is not only supple and comfortable to the touch, but also has a good balance of moderate heat retention, natural temperature regulation, moisture control, and antibacterial and deodorizing properties. However, it is not particularly good at releasing heat quickly or drying quickly when you sweat heavily. For this reason, even if there is a mid-layer made from merino wool, it alone is not necessarily sufficient to be called "active" "insulation."

That's why this jacket is made by blending merino wool with graphene . Graphene, sometimes called a "miracle new material," is said to be one of the strongest, thinnest, and most flexible fibers, boasting strength 200 times that of steel. Yet it's also light, thin, and soft. It also has antibacterial, anti-odor properties, and UV resistance. Its high electrical conductivity makes it less prone to static electricity.

However, the most noteworthy feature of all it has "excellent thermal conductivity ." Simply put, it transfers heat easily, which is convenient for quickly distributing body heat throughout the body and, conversely, for efficiently diffusing it. This is the theory behind how it keeps you warm when the temperature is low and cools you down when the temperature is high.

In other words, the combination of Merino wool's moderate heat retention, temperature regulation and moisture control properties with graphene's thermal conductivity keeps the inside of the garment warm when you are stationary and releases heat when you are moving vigorously.

Regarding graphene, Teton Bros. was one of the first outdoor brands products incorporating it , and of course I jumped on the bandwagon and started using them as soon as they were released, so I had actually been secretly aware of its potential for some time.

It has high heat retention so you can handle even the most intense winter weather. And yet, it cools down naturally when you get too hot to sweat.

So how does it actually perform? How does it compare to other competing active insulation jackets? I tried wearing it as an outer layer over a base layer while hiking during the day when temperatures ranged from 15°C to 5°C.

From the moment you put it on, you'll notice that it's much warmer than you'd expect. The highly insulating fabric made from merino wool and graphene, plus the fleece lining, creates a firm film of warm air between your skin and the garment, and the fabric is thick enough that it's not thin at all, providing just the right amount of warmth for active wear even in the harshest of winter. Conversely, I feel that the best season for this jacket is from late autumn through mid-winter, and when the snow still remains, when the cold really sets in. It may be too hot for some people at a slightly chilly temperature of around 15°C.

Also, compared to leading active insulation fabrics such as Polartec Alpha, OCTA, and Primaloft Evolve, the breathability isn't as impressive. For this reason, some people might want more breathability for high-intensity, high-tempo activities. However, the breathability is just right for leisurely hiking, and for these activities, less breathability might be more appreciated, so this is a good thing or a bad thing. The feel is similar to fleece, and in that sense, I'd say it's an " evolved fleece jacket ." In terms of fabric texture alone, it feels similar to Patagonia's R1 Thermal.

However, that doesn't mean it's too hot to wear as activewear. That's where Merinotech really shines. This test was conducted on the coldest day of the test, a ridge walk at 5-10°C. Even when exercising to the point where a thick merino wool or padded jacket would make you want to take it off, I didn't overheat to the same extent. Conversely, even when wearing it as an outer layer, I didn't feel cold from sweat. While there are limitations, it does maintain a comfortable, consistent temperature and humidity inside the garment, and it certainly fulfills the purpose of active insulation—being able to be worn throughout the entire activity. If it gets a little hot, you can adjust the temperature by opening and closing the front zipper. If it gets cold, you can pull on the hood and zip it up, and the high collar will keep out the cold. Of course, this was during the coldest test, so my impressions might have been different if the weather had been a little colder. In any case, I definitely felt that it was more than comfortable enough for activewear, just as the winter chill begins to set in.

Pockets, sleeves, and other details are designed with mountain climbing in mind.

The pocket placement is also perfectly natural for mountaineering enthusiasts, and there are just three pockets - left and right hand warmer pockets and a chest zip pocket - so there is nothing to complain about.

What's also interesting is that the long-sleeved T-shirts in this series also have a secret zip pocket on the side of the belly. This shows the determination of a workwear manufacturer that "nothing without a pocket is possible" (see photo below).

The collar is moderately high, and the hood is stretchy and fits the shape of your head, so it can be worn under a helmet. There are some minor nitpicks, such as a better fit and a chin guard-like flap at the end of the zipper, but overall it is a satisfactory design for keeping out the cold.

By the way, this hood can be folded like a collar when rolled up and fastened, so you can choose your preferred style.

A rich lineup that won't go to waste even if you buy everything, and a great price that won't hurt your wallet even if you buy everything

Finally, I'm grateful for the wide variety of items in this series. In this review, I've mainly mentioned the hoodie type, but for warmer weather, I also recommend the stand-collar type and vest type, which cover less of your body (see photo below). All of the fabrics are the same thickness.

Pants made from this fabric are also available in a climbing pants pattern. These can be used as trekking pants, as inner pants for skiing in snowy mountains, and as thermal pants for sleeping (see photo below).

Although I didn't get to try it this time, I'm sure neck warmers, balaclavas, and gloves made from this fabric, which is easy to keep warm and doesn't get stuffy, would definitely be useful, so I plan to go to a physical store after this review to get some.

Summary: The cost performance is simply too good to be true. This is an active mid-layer that you'll want to have in your wardrobe for the coming winter.

Workman Merinotech Active Insulation Hoodie, priced at under 3,000 yen, boasts complex functionality that keeps you warm while regulating your body temperature—never too hot or too cold—when you start moving. Worn between your base layer and shell, it's sure to keep you comfortable all day long during a wide range of low-temperature outdoor activities, from high mountain climbing in autumn to low mountain climbing in winter, and even mountain climbing and skiing in the depths of winter. Following on the Premium Ultra-Water-Repellent Softshell Trek Hoodie last year, we're confident this is a great product that combines high performance with a reasonable price point, sure to be a favorite among serious mountaineers.

Of course, there are some flaws to be found, such as the quality of the stitching and the fine details of each part, but considering the price range, they are not at a level that bothers you at all. Looking at Workman's products recently, it is clear that the level of perfection has improved.

The lineup is diverse. There is sure to be a model that suits a variety of situations, such as mountain climbing in the harsh winter, light winter wear for camping, and everyday work wear. If you are interested, why not check it out in store?

Learn more about and purchase Merinotech Active Insulation

It appears that they will be released in stores from September onwards, but please check the official online store