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Mountain Hardwear Nitrous Jacket Review

An ultralight down jacket that performs well in active pursuits, but it’s not the best choice for ultralight backpacking.

Overall Rating: Above Average

The Nitrous Jacket merits an Above Average rating based on its good fit (if you’re a slender person), lightweight highly water- and wind-resistant shell, high-loft down, and its versatility. It performs well for done-in-a-day active pursuits in cool conditions. However, there is unnecessary weight in its heavier front zipper and drawcord hem. And, although it’s versatile, the Nitrous jacket does not have a high loft/weight ratio and its narrow quilting is not thermally efficient, factors we consider to be important for ultralight backpacking.

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by Will Rietveld |


Mountain Hardwear Nitrous Jacket Review - 1
The Mountain Hardwear Nitrous Jacket is insulated with 800 fill-power down and has an ultralight polyester ripstop shell. It’s full-featured and has a trim fit.

The Mountain Hardwear Nitrous Jacket is designed to be as versatile as possible. It has a compact design and trim fit, moderate warmth, and a full feature set, so it can be worn as an outer layer in cool conditions or as a midlayer in colder conditions. It’s designed as a performance jacket for active alpine pursuits, but is equally appropriate for a trip to meet friends at the local pub or coffee shop, especially if you live in a mountain town. The focus in this review will be on the Nitrous Jacket’s suitability for ultralight backpacking and various cool weather silent sports.


The Mountain Hardwear Nitrous Jacket is characterized by its narrow horizontal quilting, which gives it a “down sweater” appearance. The jacket is insulated with 800 fill-power down. The shell and lining fabric is 1 ounce/square yard EcoSensor ripstop polyester (87% virgin, 13% recycled) with a DWR finish.

Mountain Hardwear Nitrous Jacket Review - 2
Front and rear views of the Mountain Hardwear Nitrous Jacket. Features include a full-height front zipper, stand up insulated collar, two hand pockets, zippered chest pocket, elastic cuffs, and drawcord hem.

Mountain Hardwear Nitrous Jacket Review - 3
There are three pockets on the Nitrous Jacket, a zippered chest pocket (left) and two side pockets (right) that are insulated but not fleece-lined. Note that the side pockets have a unique flap-over closure.

The Nitrous Jacket is available in men’s and women’s versions, and a hooded model is also available.


I tested the Nitrous Jacket over five months while mountain summer backpacking, fall canyon country hiking, and late fall mountain day hiking. I wore the jacket in camp, in my sleeping bag, and on cold/windy days on the trail.

The Nitrous Jacket has a trim fit and extra long body and sleeves. The jacket in size large fits me (6 feet, 167 pounds, 37-inch chest, 34-inch arms) very well, with room to wear a couple of thinner layers under it. The body length is 29 inches, which is about 0.5 to 1.0 inch longer than many outdoor jackets. While the jacket fits well on a skinny person like me, the same size jacket would likely be a bit tight for a stockier build.

This jacket is basically lightweight, but it has some contradictions. While the elastic cuffs and flap-over pockets minimize weight, the front zipper is a heavier #5 (compared to a #3 on a really light jacket), and the hem has a rather heavy elastic drawcord and cordlock.

I found the Nitrous Jacket to be moderately warm. Measured double layer loft is 1.25 inches (0.6-inch single-layer loft). It’s warm down to about 40F when inactive, which is sufficient for summer backpacking in the mountains. But the jacket’s forte seems to be active backcountry pursuits; I found it very comfortable while hiking on cold days and cloudy/windy days. If I got a little warm, I opened the zipper; if I felt chilly, I added a layer under it or a shell over it. The jacket’s collar is snug, but not tight, and covers my chin; however the elastic cuffs are loose.

Mountain Hardwear Nitrous Jacket Review - 4
I found the jacket’s ripstop polyester shell to be downproof as claimed, but some feathers found their way out through the numerous seams (left). Even though I tried to avoid direct contact with my skin, the collar stained badly (right). The bright orange color probably shows the staining more than other colors would.

The jacket’s ripstop polyester shell is very soft, adds an increment of warmth, and is very water- and wind-resistant. It’s not damaged by Velcro. Polyester is generally considered to be a little less durable (less abrasion-resistant) than nylon, but it is still very strong because it’s a polymer-based material, as is nylon. All jackets with an ultralight shell (1 ounce/square yard or less) require special care to avoid snagging or puncturing.

Mountain Hardwear Nitrous Jacket Review - 5
I wore the Nitrous Jacket while hiking in a snowstorm and found its shell to be quite water- and wind-resistant (left). Water readily beaded up on the shell, but the surface eventually wetted out (right, underside of sleeve). However, water did not soak through and wet the down.

Mountain Hardwear Nitrous Jacket Review - 6
I followed up my field observations with a one-hour indoor “puddle test” (left). The results confirmed my field observations - the fabric surface wetted out (right), but no water soaked through the fabric or the seams to wet the down.


The following table compares specifications of jackets similar to the Mountain Hardwear Nitrous Jacket. All jackets have premium down insulation, sewn-through construction, and a full-height front zipper. Manufacturer data for size medium are shown.

Jacket Shell Fabric Insulation Measured Single Layer Loft (in) Features Weight (oz) Cost (US$)
Mountain Hardwear Nitrous 1 oz/yd2 polyester 800 down 0.6 two unzippered hand pockets with flap, zippered chest pocket, drawcord hem, elastic cuffs 12.0 220
Rab Microlight 1.3 oz/yd2 Pertex Microlight (nylon) 750+ down 0.75 two unzippered hand pockets, zippered chest pocket, elastic cuffs and hem 11.3 190
Patagonia Down Sweater 1.4 oz/yd2 polyester 800 down 0.9* two zippered hand pockets, one inside zippered mesh pocket, drawcord hem, elastic cuffs 12.4 200
Montbell Ex Light Down Jacket 0.74 oz/yd2 Ballistic Airlight (nylon) 900 down 0.5 Stand up collar, elastic cuffs 5.7 165
*The Patagonia Down Sweater has been upgraded since BPL reviewed it in 2005. Data in the table (except loft) are for the current version.

Except for the Montbell Ex Light Down Jacket, all of the jackets in the comparison table are full featured and have narrow horizontal quilting. All of the jackets have a trim fit. The Rab Microlight Jacket has a superb nylon shell (Pertex Microlight) that makes the jacket more durable and very water-resistant (more suitable for mountaineering), and it’s also a good value compared to the Mountain Hardwear Nitrous Jacket. The Patagonia Down Sweater now has a heavier, 100% recycled polyester shell and more features, which increase the weight from the previous version. The Montbell Ex Light Down Jacket’s loft is similar to the Mountain Hardwear Nitrous Jacket, the weight is half as much, and the cost is significantly lower. However, the jacket does not have any pockets at all, and there is no hem closure.


Ultralight down jackets that are highly quilted so they have narrow down tubes, such as the first three jackets in the above table and the women’s version of many jackets, have two basic drawbacks: 1) the narrow tubes do not allow the down to completely expand, and 2) the area adjacent to each seam is not insulated at all. Hold a sewn-through down jacket in front of a window, and you will see what I mean: there's no down in the space about a half an inch along each seam. The more seams, the more cold spots (or cold lines). Perhaps the extra uninsulated space next to the numerous seams is intentional to allow excess heat to escape during high exertion activities? That would explain why the Nitrous Jacket performed well in active pursuits. Or is it simply that a thinner down sweater can be worn comfortably while other down garments cause you to overheat? Actually, both explanations account for the performance.

Yes, the quilting does hold the down in place, but properly filled down chambers (slightly compressed) do not normally have a problem with down shifting. The conventional wisdom for ultralight backpacking is that we want a jacket with a high loft/weight ratio (maximum warmth for the weight), and I will stick with that reasoning for backpacking. For active day trips, perhaps a jacket that allows excess heat to escape more easily - while still being highly wind-resistant - is the best strategy. If I get cold, I can always put a shell on over the insulated jacket.

Overall, the Nitrous Jacket is a mixed bag: it fits well (for a slender person) and performs well in active cool weather pursuits, but its loft/weight ratio is not all that good, and its narrow quilting design is not very thermally efficient. It’s also not a very good value; there are several alternative jackets available that have a better loft/weight ratio and cost considerably less.

Specifications and Features

Manufacturer Mountain Hardwear (
Year/Model 2009 Nitrous Jacket
Style Hoodless jacket with full front zip
Fabrics Shell and lining are EcoSensor 1 oz/yd2 ripstop polyester (13% recycled) with DWR finish
Insulation 800 fill-power down
Construction Sewn through with 1.75 in (4.5 cm) horizontal quilting, set-in sleeves
Loft Measured two layer loft is 1.25 in (3 cm)
Features Down-filled stand up collar, full height #5CN YKK zipper with one slider and storm flap under zipper, two side pockets (not fleece lined) with flap-over closure, zippered chest pocket, elastic cuffs, microchamois chin guard, drawcord hem with single-handed adjustor, stuff sack included
Weight Size large tested, measured weight 10.2 oz (289 g), manufacturer specified average weight 12 oz (340 g)
Disclosure: The manufacturer provided this product to the author and/or Backpacking Light at no charge, and it is owned by the author/BPL. The author/Backpacking Light has no obligation to review this product to the manufacturer under the terms of this agreement.


"Mountain Hardwear Nitrous Jacket Review," by Will Rietveld. (ISSN 1537-0364)., 2010-01-12 00:05:00-07.


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Mountain Hardwear Nitrous Jacket Review
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Addie Bedford
(addiebedford) - MLife

Locale: Montana
Mountain Hardwear Nitrous Jacket Review on 01/12/2010 15:53:06 MST Print View

Companion forum thread to:

Mountain Hardwear Nitrous Jacket Review

Matt Lutz
(citystuckhiker) - F

Locale: Midwest
Re: Mountain Hardwear Nitrous Jacket Review on 01/12/2010 16:33:50 MST Print View

Will, I'm confused. If the jacket dumps heat and is not as warm because of construction, why should I use it when a fleece or softshell would do same thing for similar weight and better breathability? Also, a fleece will hold up better under a pack. What does MH mean by active pursuits? Great review, as always.

Mark Leaman
(MLeaman) - F
Montbell EX Lite Down Jacket on 01/13/2010 07:28:41 MST Print View

Will, great review. I would just like to point out that I think the table is inaccurate about the single-layer loft of the Montbell EX Lite Down Jacket. In your separate review of that jacket, you said the single layer loft was 0.75 inches, not 0.5 inches.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Montbell EX Lite Down Jacket on 01/13/2010 09:37:20 MST Print View

The review Mark is referring to is the one Will did for BackpackGearTest. The relevant paragraph says, "Loft—The men’s Ex Light Jacket is insulated with 1.8 ounces (51g) of 900 fill-power down (size Medium). The actual amount of down in the jacket will depend on the jacket size. I measured the jacket’s two layer loft (thickness) at 1.5 in (3.8 cm), which means the single layer loft is around 0.75 in (1.9 cm). I held the jacket up to a bright light and observed that the down is very uniformly distributed. The down is held in place by a 3 in x 4 in (8 x 10 cm) sewn-through quilted pattern."

Dan Durston
(dandydan) - F

Ex Light on 01/13/2010 15:07:35 MST Print View

I guess we'll get an update on the loft of the Ex-Light next week when Will's BPL review on that jacket is released.

Lawrence Cooper
(LawrenceCooper) - MLife

Locale: Mid Atlantic
LL Bean makes better on 01/13/2010 22:36:36 MST Print View

You should check out the LL Bean Down Sweater -- it is 850 fill, better construction and costs less. I got one for XMAS and I wear it all the time.

Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: Mountain Hardwear Nitrous Jacket Review on 01/14/2010 11:23:09 MST Print View

A few things jumped out at me in the review. The "as tested" weight reported was 10.2oz, which is ~2 oz lighter than the weight given by the manufacturer and used in the comparison chart. Given that the jacket, then, is ~17% lighter than the other 12oz jackets, it seems that the weight:loft ratio is decent. The difference in weight between a jacket-length #3 and #5 zip is roughly 0.25oz, IIRC, so for a jacket zip that gets a lot of use, I wouldn't be too bothered. I do think that it's a silly, extraneous thing to add a zippered chest pocket. Probably added a solid 0.5oz with that.

Regarding baffling spacing, and at the risk of stating the obvious, I've found in designing my own down gear that the spacing controls loft. In that, if I want a light, packable jacket warm to around 40*F, I might use 2-inch spacing to keep the loft minimized; although I could get a better warmth:weight ratio by using wider spacing, the jacket would could also be "too warm"... and that might not be something I want. Personally I've found that 3-inch sewn-thru spacing is the most versatile for most 3-season needs. Allows for a bit more loft and a bit more down, but then, I tend to run a little cold in camp.

J Cruz
(DonJuan) - F
Re: Montbell EX Lite Down Jacket on 03/05/2010 16:31:08 MST Print View

It seems like somewhere there is a mistake on the listed single layer loft for the Montbell EX Lite Down Jacket. In this table it is stated as having 0.5 inches, but in the PHD Mountain Software Ultra Down Pullover Review it is stated as having 1.0 inches of single layer loft.