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The North Face Inferno -20 Review

Designed for maximum insulation at a minimum weight, this bag is a good choice for winter expeditions
The North Face Inferno -20
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Price:  $599 List
Pros:  Super warm, thermally efficient
Cons:  Half length zipper doesn't allow for venting the footbox
Manufacturer:   The North Face
By Matt Bento ⋅ Senior Review Editor  ⋅  Apr 13, 2017
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  • Warmth - 20% 10
  • Weight - 20% 5
  • Comfort - 20% 6
  • Packed Size - 15% 7
  • Features - 10% 5
  • Weather Resistance - 15% 9

Our Verdict

The aptly named The North Face Inferno -20 is one of the warmest bags in its class. It achieves this with a combination high loft down and a conservative(ish) cut. A unique, half-length two-way zipper zips in the warmth from the top of the bag and dissects a series of trapezoidal baffles. While the winds howled outside, our testers found themselves pleasantly roasting inside this high lofted heat-trapping sack. However, when warmer spring temperatures arrived, our testers were burning up and wished they could fully vent the bag.

Our Analysis and Test Results

This bag is one for the minimalists who find themselves sleeping out in the lowest of low temps. Because of the half zipper and the lack of any venting for the lower body, the Inferno -20 is only appropriate for the coldest of winter climates. What it does have going for it is an impressive warmth-to-weight ratio.

Performance Comparison

This bag uses unique, trapezoidal baffles to keep the down from...
This bag uses unique, trapezoidal baffles to keep the down from migrating around the bag and creating cold spots.
Photo: Jenni Snead


The Inferno cranks up the heat with 36.4oz of 800 fill down. The zipper is offset with the baffles on the top of the bag, so there is not a dedicated draft tube protecting the zipper. Instead, an extension of the chest baffles sits between the user and the elements. Arguably, this may work better than a closed draft tube, since it allows warm air to circulate into the zipper area. Our testers, human and ignorant to the subtle movements of hot air, didn't pick up on any cold spots near the zipper, so we feel confident in saying that this design performs as well as a regular draft tube. The draft collar contains an ample amount of snuggly down and tightens in conjunction with the dual hood cinches.


Tipping the scales at 3 lbs 7 oz, the Inferno scores toward the bottom of the competition in the weight metric. The shell fabrics make up a large percentage of the Inferno's total weight.

The Inferno uses an offset baffle instead of a draft tube to...
The Inferno uses an offset baffle instead of a draft tube to insulate the zipper.
Photo: Jenni Snead


An inch wide strip of fleecy material lines the draft collar where it touches the chin, giving a general impression of plush snugglyness. Our testers who primarily sleep on their backs felt the cut of the bag is plenty wide,The two-way half-length zipper makes it difficult to vent the footbox sufficiently, and on a warmer night where temperatures climbed into the high 20s, one of our testers (a self-proclaimed cold sleeper) felt so hot that she had to completely get out of the bag and cool off.

Packed Size

The Inferno -20 packs down smaller than the Marmot Col, but a touch larger than the Western Mountaineering Kodiak MF, since it has a heavier shell fabric and just a little bit more down. The Inferno's high fill goose down makes it much more compressible than the Kelty Cosmic Down 0, though it's almost triple the price. It's one of the few bags that comes with a stuff sack that has compression straps, which we appreciate.

The Inferno stuffed into its own compression sack.
The Inferno stuffed into its own compression sack.
Photo: Jenni Snead


The most apparent and unique feature on the Inferno -20 is the half-length, two-way zipper located on the top of the bag. This design saves a little weight, and the two-way zipper allowed our testers open up a hole in the front of the bag to stick their hands through so they were able to drink coffee and eat breakfast while remaining almost completely inside the warm bag!

The large, glow in the dark zipper pull is easy to grab in the dark...
The large, glow in the dark zipper pull is easy to grab in the dark, even with gloves on.
Photo: Jenni Snead

Again, the disadvantage of the half zipper is that you can't vent the foot box as well as a full-length zipper. The hood has a cinch cord on either side the like a jacket, but it doesn't really tighten the draft collar. Finally, a small zippered stash pocket is located inside the bag over the left side of the chest.

Between the water resistant shell fabric and the thick, 800 fill...
Between the water resistant shell fabric and the thick, 800 fill power down insulation, our testers could almost forget about how bad the weather was.
Photo: Jenni Snead

Weather Resistance

The silky feeling Neovent Air shell fabric does an excellent job of protecting the down from moisture, earning the Inferno a strong score in this metric. The shell proved itself to be truly waterproof and breathable in our submersion test: we squeezed out all the air and no water was able to penetrate the fabric and a barely detectable amount of water entered through the seams. We realize this test is beyond what these bags were designed to handle, and feel the Inferno can easily deal with the frozen forms of precip it will encounter in its natural habitat.


The Inferno -20 is a big investment. It doesn't have as good of a warmth-to-weight ratio as the Big Agnes Crosho -20, a similarly priced bag that also features a half zipper design.


The North Face Inferno -20 is an excellent bag that warmed us up and kept us cooking through the night. If you're interested in its unique design, but want less or even more(!) heat, it is also available in -40, 0, and 15-degree versions.

Matt Bento