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Sierra Designs Nitro UL 0 Sleeping Bag Review

The Nitro 0 has a half zipper to reduce weight and increase thermal efficiency.

The Sierra Designs Nitro UL 0 is a light-weight winter sleeping bag that strikes a superb stability between chilly climate options and kit weight. Weighing simply 2 lbs eight oz, the Nitro UL 0 is insulated with 800 fill energy DriDown. It additionally has a draft collar, which is arguably probably the most necessary options of a chilly climate sleeping bag,  a half-zipper to save lots of weight, and a foot vent, which helps prolong the bag’s vary to be used in hotter climate. However whereas the bag itself is properly designed and performs properly, Sierra Designs has priced it decrease than most comparable luggage. For those who’re in search of a great worth on a chilly climate sleeping bag, the Nitro UL 0 must be in your brief listing, with a number of caveats that I talk about intimately under.

A zero-degree mummy-style sleeping bag could be a snug choice in case you’re a chilly sleeper or wish to backpack and camp early in cooler climate. Whereas quilts are more and more well-liked for heat climate use, mummy luggage are far much less drafty and hotter when the mercury drops under 20 levels. Additionally they present a heat enclosure the place you possibly can retailer water, filters, and footwear in a single day to stop them from freezing. That is more durable to do with an ultralight quilt, which is often sized slender and brief to save lots of weight.

When selecting a chilly climate sleeping bag, it’s essential to get one which’s large enough that you would be able to slot in it with a few of your gear, so it doesn’t freeze at night time, together with the perspiration in your boots. Some individuals get an extended bag than wanted, to allow them to retailer gear by their ft. Sleeping in temperatures under freezing undoubtedly modifications your conduct and requires a barely totally different talent set and kit listing than common three-season tenting or backpacking in hotter climate.

The Nitro 0 has a half zipper to reduce weight and increase thermal efficiency.The Nitro 0 has a half zipper to scale back weight and improve thermal effectivity.

Nitro UL 0 Options

The Sierra Designs Nitro UL 0 is a chilly climate bag that has most of the additional options you discover on luggage designed for sub-freezing temperatures, together with a:

  • draft collar and draft tube
  • half-zipper
  • excessive fill energy insulation

Let’s take a better take a look at every of those.

Draft Collar and Draft Tube

The Nitro UL 0 has a draft collar that drapes over your chest and seals the nice and cozy air within the decrease a part of the bag so it isn’t pressured out the highest if you transfer round inside (typically referred to as the “bellows effect”). The draft collar is simply an insulated tube of down, however it’s an important component of a sleeping bag designed for chilly climate. Nevertheless, the draft tube within the Nitro is sort of easy and drapes passively over your higher chest, in contrast to greater finish luggage, together with the NEMO Sonic 0, the place you’ll be able to regulate its match for a tighter seal.

A draft tube features equally, however covers the aspect zipper to stop chilly air from leaking previous it. The draft tube is positioned adjoining to the zipper within the bag’s inside and drops over it when the zipper is closed, so your legs will really feel the insulated tube, as an alternative of a chilly and drafty zipper.

The Nitro 0 UL has a snag-free two-way zipperThe Nitro 0 UL has a snag-free two-way zipper

Snag-Free Half Zipper

The Nitro UL 0 has a half zipper, primarily to save lots of weight. A full zipper is good as a result of you need to use it to manage your temperature alongside the size of bag, and even open it up like a quilt. Nevertheless it isn’t an enormous inconvenience to swap it out for a half zipper, particularly because the Nitro UL 0 has a foot vent to assist shed warmth within the decrease half of the bag.

Sierra Designs additionally added a stiff border alongside the zipper to stop any zipper snags with the bag’s liner material and it really works very properly. Snags are extra widespread in chilly climate luggage as a result of they’ve loftier baffles that may snag in a zipper’s tooth. It’s necessary to stop them as a result of you’ll be able to simply rip the liner material and expertise vital insulation loss until you’ll be able to patch the opening shortly.

The Nitro UL 0 has a foot vent on the bottom of the bag where you can stick out your feet if you’re too warm.The Nitro UL 0 has a foot vent on the underside of the bag the place you’ll be able to stick out your ft for those who’re too heat.

Foot Vent

The foot vent helps compensate for the shortage of a full size zipper as a result of you possibly can stick out your ft in the event you’re too heat. The foot vent is a slotted opening (with overlapping material) within the backside of the bag and seals closed in the event you lie together with your decrease legs over it. Whereas the foot vent does break the bag’s thermal envelope, in actuality, you’ll be sleeping on an insulated pad, which can negate any critical warmth loss so long as your legs and the bag are positioned on the pad.

800 Fill Energy DriDown

The Sierra Designs Nitro UL 0 is insulated with 800 fill energy DriDown. This can be a chemically handled down that’s water resistant and can dry quicker than untreated down if it will get moist. Fill energy is a approach of grading the insulating high quality of goose and duck down. For instance, 800 fill energy down could be very insulating and for its weight and thought of premium high quality, whereas 650 fill energy down is heavier for a similar degree of warmth retention. See the Low Down on Goose Down for a extra detailed rationalization of down fill powers.

Nevertheless, the fill energy of the down in a sleeping bag is extra necessary than whether or not it’s been handled with a water resistant coating or not, as a result of the fill energy is likely one of the principal elements that determines the load of a sleeping bag. The upper the fill energy, the lighter weight the bag. These “waterproof”  coatings are a nice-to-have, however in actuality most individuals can forestall down from turning into compromised by moisture. Internet internet. 800 fill energy down is an effective factor, no matter whether or not it’s water resistant or not.

The Nitro's EN Standard Temperature Ratings are printed at the foot of the sleeping bagThe Nitro’s EN Commonplace Temperature Scores are printed on the foot of the sleeping bag

Temperature Score

The Nitro UL 0 has a 0 diploma temperature score that’s printed on the outside of the bag and it’s essential to know what the scores imply:

  • EN Consolation Temp Score:  15F / -9C
  • EN Restrict Temp Score:  2F / -17C

The consolation score signifies the bottom temperate the place a lady (or chilly sleeper) utilizing the Nitro UL 0 shall be snug, whereas the decrease restrict signifies the bottom temperature that a man (or heat sleeper) can stay snug. Ladies want about 10 levels extra heat than males as a result of they’ve decrease physique mass. Based mostly on these numbers, the lads’s Nitro UL 0 is equal to a 15 diploma bag for a feminine and a 2 diploma bag for a person. If that sounds shocking, it’s as a result of males’s luggage are typically longer and better quantity than the ladies’s luggage, and subsequently more durable for small ladies to warmth up.

For these scores to carry true, the person or lady must be sporting lengthy underwear and socks, they should sleep on an insulated sleeping pad, and never be uncovered to wind. These are circumstances stipulated by the outside business sleeping bag temperature score commonplace, and in case you don’t adhere to them, you’ll sleep colder and fewer comfortably than the Nitro’s UL 0’s EN temperature scores.

However there’s one other fly within the ointment. EN temperature scores are much less dependable for chilly climate sleeping luggage which have scores lower than 10 levels Fahrenheit. That doesn’t imply that the Nitro’s temperature score is essentially mistaken: it signifies that there’ll in all probability be a better diploma of interpersonal variability within the perceived heat of a Nitro 0.  See Winter Sleeping Bag Temperature Scores: Phrases of Warning for extra info on this matter. If you would like extra assurance that you simply’ll be heat in 0 diploma temperatures, get a bag rated for -10 levels.

The draft collar is an extra tube of down below the hood that drapes over your chest to seal in warmth. It's a must have on a cold weather bag. The draft collar is an additional tube of down under the hood on the within of the bag that drapes over your chest to seal in heat. It’s vital on a chilly climate bag.

The Ladies’s Nitro UL 0 Sleeping Bag

Whereas testing this sleeping bag, I observed that the ladies’s Nitro UL 0 sleeping bag had equivalent temperature scores to the lads’s. As I defined above, the EN Consolation Score predicts that the temperature score for a lady (sleeping within the males’s bag) will solely be 15 levels. I contacted Sierra Designs they usually informed me that they only copied the lads’s bag temperature scores onto the ladies’s, with out sending them out for separate testing. Not a great apply, however fairly typical within the outside business.

They found this in a current spec audit they carried out in-house (there have been inner personnel modifications) and have since despatched the ladies’s Nitro 0 UL out to have its temperature scores independently examined. If I have been you, I’d watch for these new ladies’s bag scores to be revealed earlier than shopping for the ladies’s Nitro UL 0. The ladies’s model of this bag has a unique size and quantity than the lads’s Nitro 0 UL, so the scores might change. It’s attainable that it’ll stay true to its 0 diploma product identify, however why danger it?

Comparable 0-Diploma Down Sleeping Luggage

All the 0 diploma sleeping luggage listed under have draft collars. As you see under, the Nitro UL could be very competitively positioned when it comes to weight and priced considerably lower than most different zero diploma down sleeping luggage. Whereas the fill energy and the load of the down fill in a bag is very correlated with its perceived heat, different design elements may also impact its temperature score. You’d have to spend so much extra money to purchase a 0 diploma bag that has extra down fill or down with a better fill energy than the Nitro UL 0.


The Sierra Designs Nitro UL 0 is a well-appointed down sleeping bag for chilly climate use that’s very competitively priced and an actual discount in comparison with different equally outfitted winter sleeping luggage. It’s additionally extraordinarily light-weight, which will increase its utility for backpacking, notably in early spring or late autumn, whenever you want a extra insulation to sleep comfortably at night time. Whereas the design of any chilly climate sleeping bag requires compromises between many competing value elements, Sierra Designs has achieved an admirable job of offering shoppers with a well-featured chilly climate bag at a really reasonably priced worth.

Whereas there’s nothing “wrong” with the Nitro UL 0, particularly if gear weight is your main concern, I’d advocate taking a cautious take a look at its shoulder, hips, and foot field specs and evaluating them to different luggage on the record above for the bag size you’re contemplating. I like having extra room in a chilly climate bag to retailer gear like a water bottle and boots, in order that they don’t freeze in a single day. I additionally hand around in my bag and take heed to audio books or learn in winter through the lengthy 12 hour nights.

I understand that consolation is tough to evaluate with out making an attempt every bag in individual to see in case your additional gear and stuffed animal will match inside, however it’s essential to know that chilly climate sleeping bag necessities are considerably totally different from three season ones. For those who can’t check out a bag in a brick-and-mortar retailer, purchase them on-line and return them in the event that they don’t meet your wants. There’s no upside in being depressing throughout an extended and chilly winter night time. This can be a vital sufficient expenditure, for a bag you’ll maintain for at the least 10 years, that you simply need to get it proper.

In case you’re a lady, see my feedback above concerning the ladies’s Nitro UL 0’s temperature scores. I’ll replace this publish when Sierra Designs will get their check outcomes again and updates their ladies’s Nitro UL 0 specs (if mandatory).

Examine three Costs

Final up to date: 2018-11-12 22:00:44

Disclosure: Sierra Designs offered the writer with a sleeping bag for this assessment.

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