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Therm-a-Rest Hyperion 20 Review

This super-lightweight, compact bag is a great choice for fast and light, warm-weather adventures but does sacrifice some comfort and warmth for weight
Therm-a-Rest Hyperion 20
Credit: Therm-a-Rest
Top Pick Award
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Price:  $500 List | $469.95 at Backcountry
Compare prices at 2 resellers
Pros:  Very lightweight, small packed size, high-quality down
Cons:  Tight-fitting mummy bag, not very warm, expensive
Manufacturer:   Therm-a-Rest
By Jessica Haist ⋅ Review Editor  ⋅  Jun 7, 2022
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72
OVERALL
SCORE


RANKED
#8 of 17
  • Warmth - 25% 4.0
  • Weight - 25% 10.0
  • Comfort - 20% 5.0
  • Packed Size - 15% 10.0
  • Features - 15% 8.0

Our Verdict

The Therm-a-Rest Hyperion is a great lightweight bag for fast summertime adventures. It wins our Top Pick Award for the best lightweight bag and is a great choice for activities like summer fast-packing. It is much lighter than most bags we’ve tested, but it’s also nowhere near as warm as most other products in this review. This trade-off will be worth it for those of you looking to go super light in the warm summer months where temperatures do not go below freezing. Its scant weight and tiny packed size make it a great candidate for long trips and moving fast. We love its high-quality down fill and clever half-zip design, but its price tag and niche use will give some people pause.

Compare to Similar Products

 
Awards Top Pick Award Editors' Choice Award Editors' Choice Award Best Buy Award  
Price $469.95 at Backcountry
Compare at 2 sellers
$569 List
$489.00 at Feathered Friends
$569 List
$569.00 at Amazon
$340 List
$339.95 at Amazon
$179 List
$168.95 at Backcountry
Overall Score Sort Icon
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Pros Very lightweight, small packed size, high-quality downHigh-quality down, warm, lightweightHigh-quality down, warm and lofty, light, a top tier productComfortable, lightweight, excellent materials, not constrictingComfortable, inexpensive, recycled materials
Cons Tight-fitting mummy bag, not very warm, expensiveSizing not for everyone, fabric is a bit noisyExpensiveComforter sometimes does not stay tucked inHeavy, bulky
Bottom Line This super-lightweight, compact bag is a great choice for fast and light, warm-weather adventures but does sacrifice some comfort and warmth for weightThis high-end bag will keep you warm and comfortable from Spring to Fall in all conditionsA high-tech, high-quality backpacking sleeping bag with more roomy dimensions than mostA great, high-quality choice at a relatively low price for those looking for a lightweight bag that doesn't sacrifice comfortThis well priced synthetic bag is a great choice for your car camping needs
Rating Categories Therm-a-Rest Hyperi... Feathered Friends E... Sea to Summit Flame 15 Sierra Designs Clou... Marmot Trestles Eli...
Warmth (25%)
4.0
10.0
9.0
5.0
5.0
Weight (25%)
10.0
9.0
8.0
9.0
5.0
Comfort (20%)
5.0
8.0
9.0
8.0
9.0
Packed Size (15%)
10.0
8.0
9.0
9.0
5.0
Features (15%)
8.0
9.0
8.0
8.0
7.0
Specs Therm-a-Rest Hyperi... Feathered Friends E... Sea to Summit Flame 15 Sierra Designs Clou... Marmot Trestles Eli...
ISO/EN Comfort Rating 32 F 20 F (not EN rated) 15 F 26 F 20 F
Fill Type 900-fill-power Nikwax Hydrophobic goose down Goose down Goose down PFC-Free DriDown HL-ElixR synthetic fibers
Measured Weight 1.2 lbs 1.7 lbs 2.0 lbs 1.7 lbs 2.8 lbs
Total Weight 19.0 oz 27.5 oz 31.2 oz 27.4 oz 44.0 oz
Fill Power 900 950+ 850+ 800 Synthetic
Women specific features Available in a "Short" length, which is a standard women's size Extra fill in footbox and chest Women's specific fit - more insulation in key areas More insulation per square inch than men's version Women's specific fit
Fill Weight 12.0 oz 17.3 oz (medium) 22.9 oz 14.8 oz Unspecified
Material 10D Nylon RipStop w/ DWR Pertex Endurance UL Ultralight 10D Nylon Shell 15d nylon risptop 20-denier recycled ripstop polyester
Neck Baffle No Yes Yes No Yes
Pocket No No No No Yes
Sleeping Pad Sleeve Removable attachment straps No No Yes No
Zipper Length 35 in 62 in 56 in N/A 53/15 in
Shoulder Girth 55 in 54 in 60 in 59 in 58 in
Hip Girth 48.5 in 56 in 58 in 58 in 58 in
Foot Girth 36 in 38 in 40 in 39 in 45 in
Stuff Sack included? Compression sack and storage bag included Stuff sack and storage bag included Compression stuff sack and storage bag included Stuff sack and storage bag included Stuff sack and storage bag included

Our Analysis and Test Results

The Therm-a-Rest Hyperion 20 is a great choice for warm-weather, lightweight backpacking adventures. If you’re looking to move quickly with a lightweight pack, this could be the bag for you. You will sacrifice some creature comforts and warmth to have more comfort on your back carrying it around.

Performance Comparison


Therm-a-Rest Hyperion 20 sleeping bag womens - the therm-a-rest hyperion is a great choice for fast and light...
The Therm-a-Rest Hyperion is a great choice for fast and light adventures.
Credit: Ian McEleney

Warmth


Because it is a unisex model, the Hyperion’s temperature rating is different from the other women's-specific bags in this review. Therm-a-Rest rates this bag to the EN “Limit” rating, which in this case is 20F versus the “Comfort” rating of 32F. This is different from the other women’s specific bags we’ve tested, which use the “Comfort” rating in their naming conventions, but this seems to be the way that Therm-a-Rest rates all their bags. This is definitely something to note when you’re comparing the Hyperion to other products in this review. This bag’s Comfort rating is to 32F.


We took this bag out on a chilly September night and we’d say that rating is just about right. As the temperatures dipped towards freezing in the wee hours of the morning, we felt chilly but never cold. Arguably, for our testers, the "limit" of this bag is 32 degrees. We like the Hyperion’s half zip as it prevents drafts coming through the zipper and its snug hood does the same.

Therm-a-Rest Hyperion 20 sleeping bag womens - the hyperion's snug hood helps keep warmth in, as does its...
The Hyperion's snug hood helps keep warmth in, as does its tight-fitting silhouette.
Credit: Ian McEleney

The Hyperion is a very snug-fitting bag, especially around the legs. This means that there is less cold air around your body that needs to get heated up, but it also means there is less room to put on extra layers. For broader shouldered or hipped individuals, this may mean you can't put that extra layer of puffy pants or jacket on.

Weight


The Hyperion blows the competition out of the water in this category. Therm-a-Rest has really shaved the ounces wherever they could.


Weighing only 19 ounces, it’s half a pound lighter than its closest competitor. As we mentioned in the warmth section, the Therm-a-Rest Hyperion trades off some of its warmth for those extra ounces. Things that help contribute to the Hyperion's feather-lightness are well, its feathers. Its high-quality 900 fill power down means that it is a lot warmer per square ounce compared to other bags that have lower quality 650 fill down that is heavier and requires more to equal the amount of warmth of a 900 fill product. We also like its clever half-zip that shaves a few more grams off the Hyperion's weight.

Therm-a-Rest Hyperion 20 sleeping bag womens - we like the hyperion's clever half-zip design; it reduces weight and...
We like the Hyperion's clever half-zip design; it reduces weight and helps stop drafts from getting through the zipper.
Credit: Ian McEleney

Comfort


Again, in an effort to slim down the ounces, the Hyperion has a trimmed down silhouette that makes for quite a snug fit.


We tested the “Small” size and our 5-foot, 5-inch tester just barely fit length-wise. She was able to get the hood over her head and was quite cozy; however, we think most folks who aren’t used to a snug mummy fit will not feel comfortable in this bag. There is very little legroom (your legs are essentially pinned together in the bag), but there is an articulated foot box so your feet don’t feel squished. Its shoulder girth is an average of 3 to 8 inches narrower and its hip girth is 6 to 10 inches narrower than most bags in this review. The Hyperion is all about its low weight, and you sacrifice comfort noticeably for fewer ounces. We do think that this snug fit helps keep the warmth in. This bag also only has a half-length zip and some people will find this less comfortable if they want to fully unzip if they're feeling warm or just want to stretch out.

Therm-a-Rest Hyperion 20 sleeping bag womens - the hyperion is a tight fit for our 5'-5" tester and snug all the...
The Hyperion is a tight fit for our 5'-5" tester and snug all the way around the body and legs. The articulated foot box helps your feet feel more comfortable.
Credit: Ian McEleney

Packed Size


This bag packs down to a tiny little capsule and gets really small. We like that the Therm-a-Rest Hyperion comes with a compression sack to make it even smaller than a traditional stuff sack would.


It also comes with a larger storage sack so you can store it un-compressed. This is a best practice for any sleeping bag as it helps retain its loftiness over time.

Therm-a-Rest Hyperion 20 sleeping bag womens - the hyperion's packed size is tiny, as seen here next to a 1 liter...
The Hyperion's packed size is tiny, as seen here next to a 1 liter Nalgene bottle.
Credit: Jessica Haist

Features


The Hyperion’s features are all about weight savings, which we think is great. It has a really high quality down fill of 900, which increases its warmth to weight ratio, and the half-length zipper shaves a few grams.


This bag also comes with “SynergyLink™ Connectors” which are essentially removable straps you can use to attach your bag to your sleeping pad if you’re one to roll off your sleeping pad. We really like that they’re removable and appreciate the simple attachment system - this is the best pad attachment system we've tested because it's so minimal and light. Another weight-saving feature is the Hyperion's tiny gauge zipper - although it does not have an anti-snag feature like many other products in this review.

Therm-a-Rest Hyperion 20 sleeping bag womens - the hyperion's sleeping pad straps are very small and lightweight.
The Hyperion's sleeping pad straps are very small and lightweight.
Credit: Jessica Haist

Value


Even though the Hyperion has high-quality materials, we think the price tag is a little steep. There are other products in this review that you get a lot more bang for your buck than with the Hyperion. However, it is one of the lightest bags we’ve found that’s sized for smaller people. If the conditions and mission are right, it could be worth the money for you.

Conclusion


The Therm-a-Rest Hyperion 20 is a great choice for fast and light summer adventures and is our Top Pick for the best lightweight sleeping bag for women. This is a very snug-fitting mummy-style bag that’s comfort rated to 32 F, so be sure you’re ready to sacrifice a bit of comfort and warmth for a tiny, lightweight package. Therm-a-Rest has taken great strides to slim down the weight of this bag, using high-quality materials, and trimming the ounces any way it can like with a half-zip and snug-fitting shape. If you’ll be spending lots of time carrying your stuff around, trying to move fast and cover lots of ground, and don’t think the temperatures will go below freezing, this bag could be a great choice for you, if you’re willing to pay the price financially and comfort-wise.

Jessica Haist
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