After testing my third Sierra Designs product this summer, I’m becoming convinced that Sierra Designs is on a roll. I’ve tossed around a Mojo 2 tent, a Revival 50 pack, and now the Nitro 15 800-fill down sleeping bag which capped off my SD camping experience.

Sierra Designs Nitro 15 Features:

  •  Ergonomically shaped footbox
  •  Removable pad locks™
  •  Snag-free zipper tracks™
  •  Draw cord at collar
  •  Draft collar
  •  Ultralight footbox vent (12″)
  •  Offset ultralight jacket zipper (30″)
  •  Ultralight Jacket Hood™
  •  Partial Flex™ on the exterior torso
  •  Zipper draft tube
  •  EN Tested
  •  Includes stuff and storage sacks
  • MSRP: $399-419

Sierra Designs Nitro 15 Sleeping Bag Review

With the Nitro 15, Sierra Designs set out to create the perfect bag for ultralight backpackers.  At 2lbs 2 oz. it’s lighter than virtually everything but a quilt; it even edges out the more expensive MontBell U.L. Super Spiral Hugger by a single ounce – not bad at all. In fact, unless I am mistaken, the Nitro 15 is the lightest 800-fill bag on the market.

The Nitro, all packed up in the supplied stuff sack, next to a standard 1L Nalgene

The Nitro is more than just lightweight – it’s comfy. Sierra Designs utilizes their FLEX technology to help the sleeping bag move with the user. FLEX is pretty simple, but it works well; elastic threads around the bag’s torso softly constrict the down, allowing the bag to conform to the body and pretty much eliminate dead air space.

The Nitro has a comfortable jacket-style hood which offers a different fit than standard mummy bags. This is very much a matter of personal taste, but I really like the jacket hood.  I especially like the down baffle running along the length of the drawstring that eliminates any roughness from the string.

Sierra Designs chose YKK coil zipper in an anti-snag track. I like how easily the zipper slides and the track eliminates the majority of snagging, but I wish SD produced a right-handed zip as an option.  I was wondering how the half-length zipper would turn out, and in practice it does just fine – totally worth the savings in weight. The zipper also has a nice fat draft tube to block out an Arctic breeze.

The Nitro’s zipper track

One of my favorite features was the 12-inch foot box zipper which is invaluable on warm nights.  Since feet sweat so readily, the foot zip was wonderful in preventing overheating in that area.

Speaking of temperature, how does the Nitro do? When I was researching this bag, the word on the street was that the Nitro 15 ranks as one of the warmest bags in its temperature rating.  I never had temps below the low 40’s this summer, but I would have no qualms taking this down to its lower limit of 15 F. The FLEX technology does such a good job eliminating dead air space, the jacket hood retains the head’s heat, and the excellent 800 fill rating combine for a toasty-warm experience.

Speaking of baffles, it’s worthwhile to discuss SD’s horizontal baffle design. Horizontal baffles make it easier to push the down around the bag since it does little good compressed under the sleeper. The new trend is to use vertical baffles, which stop cold spots from forming on the sleepers’ top as down shifts in the night. Vertical baffles also reduce the number of baffles required, slightly reducing overall weight. SD might be a little behind the trend on this one and I’d be interested to hear their reasoning in using horizontal baffles. For what it’s worth, SD’s Cloud 15 (a 900 fill down that is the flagship of their non-DriDown line) features vertical baffles.

The bag has a DWR (Durable Water Repellant) finish that does a pretty good job in light, spotty moisture. It’ll definitely get damp when the bag is pressed up against a wet tent all night, but I was pleased to note that the moisture never reached my toes.

Before concluding, a word about fabric choice: the 20D nylon ripstop SD chose has a nice touch, and it’s the kind of bag that has something of a luxurious feel. I thought the light grey color of the inner liner was an interesting choice – it may show stains better than darker shades other bags employ. My biggest problem is chapstick staining, and they show up pretty well on this color.

Good Nitro 15:

  • FLEX technology is fantastic
  • Uber-comfy jacket hood
  • Very warm
  • Lightest in its class
  • DWR coating sheds moisture
  • Easy-pull zipper

Bad Nitro 15:

  • Vertical baffles would be a good touch
  • Left or right zipper choice would be nice
  • Nylon lining color choice shows stains

Bottom Line: Sierra Designs Nitro 15

All in all, the Nitro 15 is one of the best sleeping bags in its range – those looking for an awesome sleeping bag near the top of the pile will be well-satisfied with the Sierra Designs Nitro 15. Its low weight, warmth, comfort, toe box zipper and cushy jacket hood combine to make the Nitro 15 an absolute winner.

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About Author

Kevin Glover is an outdoorsman living, climbing and biking in Spokane, WA. Originally from the Nevada high desert, he moved to the PNW for its mild winters and allergen-free summers. He has guided throughout the Cascades and Enchantments for Peak 7 Adventures.

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