Marmot Hydrogen Review
Compare prices at 2 resellers Pros: Packs down really small, low weight, extra zipper for venting
Cons: Narrow footbox, cheap hood drawstring, fragile accessory zipper
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Our Analysis and Test Results
Marmot leaves a nice buffer between the Hydrogen's advertised and tested temperature rating. They market it as a 30° bag while it receives a 23°F rating on the industry-standard EN test. As you might guess, our testers think it feels a little warmer than its advertised rating. It supplies this warmth with 13 oz of 800 fill power down, which is a decent amount considering the bag's narrow dimensions.
At 1.73 lbs for size Long (which we tested) and 1.4 lbs for size Regular, this bag is slightly ahead of the field in terms of weight. When you factor in its above-average warmth, it equates to an overall above-average warmth-to-weight ratio. This is surprising if you consider that the Hydrogen provides roomier dimensions and some additional features you won't find on other light bags that are fully optimized for minimum weight.
One of the ways the Hydrogen achieves its impressive warmth-to-weight ratio is through its narrow dimensions. With 61 inches of shoulder girth, the upper body section of the bag actually supplies adequate space. The same cannot be said as the bag tapers toward your feet. The footbox, in particular, feels uncomfortably constrictive. We also heard complaints about the drawcord used to seal up the hood. It's flimsy with a pointy melted tip that had a habit of floppy around and scratching our testers faces.
Considering this bag's near average weight, it performs impressively well when it comes to packed size. With the help of an aftermarket compression sack, we were able to squeeze it down to 6.8L, which is just fractions of a liter more than the smallest 3-season sleeping bags we've tried. The stuff sack it comes with, however, is of the simple drawstring variety so if you hope to enjoy the super small packed size we observed, you'll need to buy a third party compression sack.
To boost your options for venting excess heat the Hydrogen is fitted with a 14-inch auxiliary zipper positioned opposite the main zipper near the head of the bag. When opened, this allows you to fold down the collar and let your neck and upper chest breathe. It's a nice feature, but we're not fans of the tiny zipper it relies on because it's so prone to snagging.
Features & Design
Inside the bag is a slim zippered pocket that's just large enough to stash an iPhone X. The main zipper incorporates a Y-shaped slide that's designed to reduce snags. We found it to be modestly successful at this goal.
We're not happy about the hood drawstring made of supple string because it often dangles down to irritate your face. We also dislike that the useful accessory venting zipper is sewn fully into the bag which makes it a serious chore to fix if it becomes misaligned.
This bag retails near the average for a 3-season backpacking sleeping bag, and it's been around long enough that we occasionally see it on sale. At full price, we consider it an OK value, but there are a few other bags priced competitively that we like a little more, such as the 850 fill power REI Magma 30. If you're able to find the Hydrogen at a decent discount it could still be worth considering.
The sleeping bag market is a crowded place, and this bag does little to separate itself from the field. Its accessory zipper is perhaps its most distinguishing trait but this feature is compromised by durability concerns. If you're on a budget, the Marmot Hydrogen should be on your radar. But only if you're able to find it on sale.
— Jack Cramer