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Hands-on Gear Review
Rab Ascent 900 Review
Cons: Heavy, zipper snags
Bottom line: This bag is heavy on the warmth and light on the wallet.
Fill Weight (oz): 31.7oz
Material Weight (excludes down, oz): 20.98oz
The Rab Ascent 900 is a great bag for those looking to camp in colder weather but don't want to pay the high price for a lighter bag. Our testers found it to be warmer than its closest competitors, the Big Agnes Storm King 0 and the Kelty Cosmic Down 0. A wide cut makes it comfortable for back and side sleepers. While not the lightest bag, the highly weather resistant shell, lofty 650 fill power duck down, and excellent features earn it our Best Bang For Your Buck Award. For a cool $350, you can jam out into the hills for some fun without freezing at night when the temps are dipping into the low teens.
RELATED REVIEW: The Best Winter Down Sleeping Bags of 2017
Our Analysis and Hands-on Test Results
This budget-priced bag doesn't cut the corners where it counts. While it's not as light as the Mountain Hardwear Torch 3 or the Western Mountaineering Versalite, or as warm as the Antelope MF, it is just light enough for shorter trips into the backcountry where it will do its main job sufficiently, keeping you warm and dry, without draining your bank account.
Warmth is perhaps the most important consideration in a cold weather bag, and our testers found that this budget-friendly bag kept them toasty on nights in the upper teens, and downright hot on some nights in early spring. Fortunately, there is a two-way zipper for venting. This bag isn't as warm as lower rated, more expensive bags like the Feathered Friends Snowbunting or the Editors' Choice Brooks Range Drift -10.
It is warmer than the Nemo Sonic because it has more down and more loft, but the down isn't as quality as the 800 fill down of the Sonic, thus the Ascent is 12oz heavier. We found that wearing a down jacket inside the bag helps to fill up the dead space left by the roomy cut when pushing into lower temperatures. Boots and layers shoved into the wide foot box also help insulate our feet when they felt cold from the extra space.
The Ascent 900 features 650 fill duck down - 31.7oz of it to be exact. Duck down doesn't have as much fill power as the high-quality goose down found in the similarly weighted and much warmer Brooks Range Drift -10 but it's much less expensive. This bag doesn't have the best warmth-to-weight ratio, but the Ascent erred in favor of warmth, and our testers agreed that carrying some extra weight was worth the effort. Carrying a few more ounces is better than spending the night shivering in a limp, un-lofty sack. If you consider yourself a warm sleeper, check out the REI Co-Op Magma 10. It's not as warm as the Rab Ascent, but it is significantly lighter.
The highly weather resistant Pertex shell fabric also keeps the weight lower than the Ascent's closest competitors. The Ascent 900 is a full 13oz lighter than the Kelty Cosmic Down, and 2oz lighter than the Big Agnes Storm King 0. Top Pick For Comfort, the Nemo Sonic, has a wider cut and is 12oz lighter, but our testers agreed it wasn't as warm as the Ascent.
This generously cut bag takes a middle of the road comfort metric. It is roomy in the foot box and in the hood, but not as wide in the middle as the Brooks Range Drift -10, the super spacious Big Agnes Storm King, or our Top Pick for Comfort, the Nemo Sonic.
Our testers that sleep on their backs had plenty of room to cross their legs or splay out their feet, but the middle and shoulders of the bag weren't wide enough to sleep as comfortably on their sides as in the wider cut bags. The hood is deep and comfortable, keeping our noggins toasty when cinched tight. We wished that the draft collar was just a little bit thicker.
Again, duck down doesn't compress quite as well as its loftier goose cousin, but the Ascent still compresses better than the Kelty Cosmic Down. The Big Agnes Storm King is a little bit more compressible, because it has less down in it, relying on its integrated pad system to insulate the bottom of the bag.
The equally warm and 19oz lighter Western Mountaineering Versalite compresses much smaller and would be a much better choice when weight and pack space are important.The Pertex shell feels tougher than the shells on some of the lighter bags, which is great if you're like our lead tester and prefer to forego the stuff sack and just cram the bag in the bottom of your pack, stuffing the rest of your gear on top of it.
This bag is one of the few models that comes with its own compression sack, making it easier to pack it as tightly as possible.
The Ascent 900 has similar features to some of the more expensive bags in our review. The full-length draft tube running the length of zipper prevented our testers from feeling cold and moisture on the zipped side of the bag. The draft collar hangs down nicely over the chin, but it doesn't have its own dedicated cinch cord like on the Mountain Hardwear Torch 3, or the Nemo Sonic.
A small zipper accesses the stash pocket located within the draft collar, which is large enough for a headlamp and a phone. The zipper is lined with an anti-snag tape, but we still managed to get the zipper snagged frequently in the dark of night. The hood features a cinch cord that tightens down around the top and the bottom of the hood. This bag arrived with a large storage sack and compression sack. We found that the Ascent 900 can compress much smaller in our smaller compression sack than in the included stuff sack.
We found this model to be significantly more weather resistant than the Kelty Cosmic Down and slightly better against the elements than the Big Agnes Storm King. For the price, we are super impressed that this bag holds up so well against frozen and not so frozen precip. The Pertex microlight shell fabric does an excellent job of repelling water. In our light rain testing, water beaded and puddled on top of the bag, but didn't absorb through the shell or the seams.
In our submersion tests, we found that the Ascent absorbed slightly more water than the Nemo Sonic. The Ascent's 650 fill power duck down features Nikwax hydrophobic treatment, which may help the bag dry out faster. Our testing showed that the most important factor in retaining loft and speed of drying time is the water resistance of the shell fabric, and the Ascent does this as well as its lighter weight and more expensive competitor, the Western Mountaineering Versalite.
In a long expedition where minimizing weight is paramount, this bag is a bit on the heavy side. For shorter backpacking trips, quick overnight spring ski tours, and car camping in cold destinations, like chilly nights in Indian Creek, this bag is a great option.
Due to its weight, comfort, and great weather resistance, the Rab Ascent 900 gets our Best Bang for your Buck Award! This bag has some killer features for only $350. It has weather resisting capabilities equal to bags that are almost twice the price. It is heavier than some of the more expensive bags in this review, but will still keep you warm when the temps start to drop.
This bag is a steal for those who want to camp in the cold without breaking the bank. This contender is an incredible value and scores higher in all the metrics than the super budget friendly Kelty Cosmic Down 0. We feel it's an awesome balance of value and performance.
— Matt Bento
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