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Marmot Reactor Review

This no frills fleece is warm, breathable, and layers well, all for an excellent price
Marmot Reactor
Marmot Reactor
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Price:  $104 List | $78.00 at Amazon
Compare prices at 2 resellers
Pros:  Lightweight, easy to layer, breathable, drawstring hem
Cons:  Not very warm, no hood
Manufacturer:   Marmot
By Matt Bento ⋅ Senior Review Editor  ⋅  May 17, 2017
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  • Warmth - 25% 5.0
  • Comfort - 20% 8.0
  • Breathability - 15% 7.0
  • Layering Ability - 15% 8.0
  • Style - 5% 8.0
  • Weather resistance - 10% 6.0
  • Weight - 10% 10.0

Our Verdict

The Reactor has been updated since we tested it.

There are plenty of folks out there who will spare no expense, shelling out big bucks for the most deluxe, high performing outdoor clothing. Then there are those of us who spend as little as possible, so we can spend as much time as possible on the road, climbing, skiing, and having fun! The Marmot Reactor is the fleece for the dirtbag adventurer who needs a warm mid-layer without all the bells and whistles. Though this contender is nearly half the price of the Editors' Choice Award Winning Patagonia R3 Hoody, it packs a punch where it counts. Comfort, breathability and layering ability are our main concerns when shopping for a fleece jacket, and the Reactor nails it in each of these metrics, easily taking home our Best Buy Award for the third year in a row. If you're trying to stay warm on the cheap, take a look at the Columbia Steens Mountain, which kept our testers cozy for only $35, but couldn't match the performance of our Best Buy Award winner.

Our Analysis and Test Results

This jacket is made of Polartec Classic 100, which is 100 percent polyester microfleece. The flatlock stitching adds comfort and dexterity. It features a regular fit that works for different body types and has two zippered handwarmer pockets along with a zippered left arm pocket. The elastic drawcord hem is a great feature that allows the wearer to adjust the amount of airflow and temperature quite easily. The flap behind the zipper blocks out the wind and also attaches to a chin guard for added comfort. Current color options: black, cinder (shown in the main photo above), denim, surf, alpine green, and dark crimson.

Performance Comparison

Marmot Reactor fleece jacket - the best buy winner in all its glory.
The Best Buy winner in all its glory.
Credit: Matt Bento


This fleece is the second lightest jacket in our selection, even lighter than the super thin Black Diamond CoEffiecient Hoody, but not as light as the featherweight Outdoor Research Transition Hoody. Our testers were surprised that it felt so warm. For the weight, it is an excellent insulator, making it a great piece for chilly mornings that you can throw in your pack and forget about once the day starts to heat up or to carry into the mountains where you never know what the weather might throw at you. While not as warm as heavier fleeces like the Mountain Hardwear Monkey Man Grid II, the lighter weight makes for a better layering piece.

While this jacket isn't the warmest fleece we tested, we don't think you'll find anything much warmer with the same weight and thickness. Our testing indicated that the warmest fleece jacket in our review was The North Face Denali 2, which scored the only perfect 10 out of 10, followed by the Patagonia R3.

Marmot Reactor fleece jacket
Credit: Matt Bento


This fleece scores a solid 8 in the comfort metric. Against our skin, the Polartec Classic Micro 100 fabric feels soft and cozy. We wouldn't think twice about wearing this jacket through the night for a little extra warmth in a sleeping bag. The cut is athletic with a generous amount of stretch, so it never felt too tight, even on our broader shouldered testers.

The collar zips up just underneath the chin and feels warm against the neck without being too tight as to restrict movement. The cuffs are a bit loose, which is excellent for those who like to pull their sleeves way up past their elbows, but not so good for moving around underneath other layers. We weren't crazy about the elastic drawstring around the hem of this jacket. It causes the zipper to bunch up, and when pulled tight, the whole hem rides up. We prefer a hem with a tighter fit and more stretch like the one on The North Face Fuseform Progressor Hoodie. This design does a better job of keeping breezes out without restricting movement or causing the jacket to ride up.

Marmot Reactor fleece jacket - the reactor has what it takes to keep us comfortable during various...
The Reactor has what it takes to keep us comfortable during various activities.
Credit: Matt Bento


Because this jacket is so thin, it breathes fairly well, but not as well as the grid patterned Patagonia R1 Hoody, which is also warmer due to its high loft.

Our breathability testing included hiking up the steep gully out of the Owens River Gorge in each of the jackets, and the Reactor breathed better than the "hard faced" jackets like the Arc'teryx Fortrez Hoody. In every fleece, we managed to get pretty sweaty, but the Reactor moves moisture and dries quickly, keeping you warmer on breezy summits or during transitions on a ski tour. The most breathable jacket in our review is the Outdoor Research Transition Hoody

Marmot Reactor fleece jacket - the reactor does well in the breathability metric. shown here is the...
The Reactor does well in the breathability metric. Shown here is the draw cord, allowing us to pull it snugly against our waist.
Credit: Matt Bento

Layering Ability

On its own, this jacket can only handle light-duty conditions, but underneath a shell, it insulates wonderfully as a mid layer. The athletic cut lends itself well to sliding into a shell or underneath a puffy jacket and scored an above average 7 out of 10.

While we prefer jackets with hoods, the lack of such a luxury on this fleece makes for better layering, since it doesn't bunch up the hoods on other layers. We do wish this model had thumb loops, as they would keep the sleeves in place when putting on additional layers; another solution is tighter fitting cuffs. Top scorers for this metric include the Patagonia R1 and the Black Diamond CoEfficient Hoody.

Marmot Reactor fleece jacket - the cuffs are loose - we would be psyched to see thumb loops.
The cuffs are loose - we would be psyched to see thumb loops.
Credit: Matt Bento

Weather Resistance

No fleece is expected to hold up against heavy conditions like rain or snow since they are primarily designed to insulate. However, it's nice to know how a fleece performs as a standalone piece against the elements. Like the Majority of the jackets in this selection, the wind cuts through the Marmot reactor. Fortunately, due to its layering ability, it fits well under a light wind layer.

This jacket fares better against the rain than the Black Diamond CoEfficient Hoody and The North Face Fuseform Progressor Hoody, repelling mist and very light rain. When the precip ramps up to anything more than a drizzle, you'll want to put on a hard shell or a rain jacket. If you're looking for a similarly light fleece that does better alone against the rain, check out the Arc'teryx Fortrez Hoody. Its hard face outer layer will repel water better, but you'll be paying double.

Marmot Reactor fleece jacket - relaxing in all types of environments is something that the reactor...
Relaxing in all types of environments is something that the Reactor excels in.
Credit: Matt Bento


Slim and trim, this jacket weighs in at 12.7, making it the second lightest jacket in our selection, behind the Outdoor Research Transition Hoody. While there aren't any bells and whistles or a hood on this jacket, it's insulating capabilities are uncompromised. Its warmth-to-weight ratio is excellent, especially considering the price, easily snagging it our Best Buy Award.


The Reactor is a good looking jacket, riding the line between style and function with ease of highliner over Yosemite. This fleece looks just as good over a nice flannel with some jeans as it does with your ratty old base layer and torn up climbing pants. It's also available in loads of color options.

Best Applications

For cool hiking conditions in early spring and late fall, this jacket is a worthy choice. The shorter cut and the location of the handwarmer pockets don't make it ideal for climbing, but we'd use it in a pinch, as the stretch doesn't restrict movement. This jacket was also perfect under a shell on a gloriously sunny spring day at the ski resort.

Marmot Reactor fleece jacket - sharing beta (while testing the reactor) and finishing out a great...
Sharing beta (while testing the Reactor) and finishing out a great day.
Credit: Matt Bento


If you're on the hunt for the best value, look no further. Though the Columbia Steens is less expensive, it doesn't perform nearly as well. The Reactor is still half the price of the most expensive jacket in this review and it's got the goods. It'll keep you warm, breathes well, and layers like a cham - all for a cool $99.


This Best Buy winner is a comfy, versatile jacket that won't spend much time in your closet. Its light weight makes it a no-brainer to throw this jacket in the top of your pack for all but the hottest endeavors.

Matt Bento
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