The North Face Inferno -20 Review
Cons: Half length zipper doesn't allow for venting the footbox
Manufacturer: The North Face
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.
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.
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.
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 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!
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.
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