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Marmot Isotherm Jacket

- published April 2017

82

2017

RATINGS

Durability
7
Breathability
7
Weatherproofing
6
Fit/Comfort
7
Compressability
8
Features
7
GEAR INSTITUTE RATING
82

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MSRP
LOW PRICE
$225.00
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THE GOOD

  • Good wind resistance
  • Excellent abrasion resistance
  • High compressibility
  • Lightweight

THE BAD

  • Too warm for highly aerobic activities
  • Torso too short for harnesses
  • No hood option in 2017 version

THE VERDICT

The Marmot Isotherm Jacket’s calling is moderately active pursuits like hiking and rock climbing in temperatures around freezing. The highly abrasion resistant Pertex Quantum shell resists wind well, making this active insulation layer better in winter conditions but limits breathability for more active pursuits or warmer conditions.

FULL REVIEW

Breathability
The Marmot Isotherm Jacket’s Polartec Alpha insulation, Polartec Power Stretch Pro under arm and side paneling and open mesh interior back panel lining are all highly breathable but the 20d Pertex Quantum exterior shell is the bottleneck to vapor and heat escape. This makes the jacket best for more moderately aerobic activities in colder climates. 

Durability
The Pertex Quantum exterior shell proved highly abrasion resistant throughout the test, emerging unscathed from repeated bouts of squeezing between boulders and almost continuous use with backpacks. The Power Stretch Pro panels are thin and airy, making them prone to snagging, although they weren’t damaged throughout the testing period. 

Weatherproofing
The Marmot Isotherm Jacket scored high in wind resistance, which contributes to it being one of the warmer items tested. This jacket also has a massive storm flap behind the main zipper, aiding both wind resistance and warmth. The Pertex Quantum portions of the outer shell are DWR treated and shed light precipitation well compared to others in this category. Since this jacket is one of the warmer choices better suited to less intense pursuits, it received a minor ding for not having a hood available in the 2017 version. 

Fit/Comfort
The Marmot Isotherm Jacket is athletically cut, but still provides enough interior volume to use midweight layers underneath. The “Angel-Wing Movement” pattern keeps the wrists covered when reaching overhead without the use of overly long sleeves. The torso is a little short to stay tucked in climbing harnesses. The Power Stretch Pro panels are key for mobility as the rest of the jacket doesn’t provide stretch. The bottom hem is adjustable via a single cord lock on an elastic drawstring but the wrists are simply bound with elastic.

Compressibility
The Marmot Isotherm jacket is highly compressible for its warmth, stuffing down to just slightly larger than a 1-liter water bottle. This allows it to be considered a “just in case” insulating layer that can provide a lot of warmth while moving in exchange for a little corner of the pack.

Features
The Marmot Isotherm jacket has just the right number of usable pockets: two zipped handwarmer pockets (do not clear pack hip belts), one vertically aligned zipped chest pocket, and one interior mesh dump pocket that was perfect for keeping gloves and a hat warm and accessible. 

How We Tested It

The jackets in this test were used over a three-month period in Central Texas winter/spring conditions while guiding, hiking, rock climbing and mountaineering in Central Mexico. This tester is 6 feet tall, has a 32” waist and weighs 167 lbs.

For more reviews beyond this 2017 test, check out our Best Softshells of 2017, Best Synthetic Sweaters of 2017, along with our insulated jacket tests, softshell jacket tests, and other related hiking and camping gear tests.

The products featured in this test have been loaned to the Gear Institute. For more on our policies regarding editorial objectivity and sample returns, see here.

About the Author

Seiji Ishii

Seiji Ishii

Seiji Ishii works as a trainer to professional supercross/motocross riders, adventure based motorcycle testing contributor at multiple outlets, and as an AMGA certified rock climbing guide/instructor for White Star Mountain Guides/Austin Rock Gym. His personal time is spent rock climbing, any form of dirt biking, cycling, and training for the next mountaineering adventure.

Shop for the Marmot Isotherm Jacket

MSRP
LOW PRICE

$225.00
Support Gear Institute. If you make a purchase after clicking on the links above, a portion of the sale helps support this site.

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MSRP
LOW PRICE
$225.00
Support Gear Institute. If you make a purchase after clicking on the links above, a portion of the sale helps support this site.

RATINGS

Durability
7
Breathability
7
Weatherproofing
6
Fit/Comfort
7
Compressability
8
Features
7
GEAR INSTITUTE RATING
82

Weight

.82 lbs

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