Therm-a-Rest Hyperion 20
The Therm-a-Rest Hyperion 20 hits a sweet spot for a three-season sleeping bag, combining a nearly unbeatable light weight with warm 900 fill down.
Therm-a-Rest Hyperion 20 Specs
MSRP:
- Small: $469.95
- Regular: $549.95
- Long: $579.95
Weight:
- Small: 1 pound, 3 ounces
- Regular: 1 pound, 4 ounces
- Long: 1 pound, 6 ounces
Shell: 10 denier nylon ripstop with a durable water repellent (DWR) coating.
Temperature Rating: Comfortable for sleeping to 32F; the lower limit is 20F; the extreme limit is -9F.
Insulation: The Hyperion is packed with 900 fill Nikwax hydrophobic goose down, water resistant down that follows the Responsible Down Standard certifying that waterfowl in the food supply chain are treated humanely.
About the Hyperion 20
The Hyperion 20 is a stripped down, ultralight sleeping bag good for three-season backpacking. Therm-a-Rest achieves ultralight status with the Hyperion by giving it high warmth-to-weight 900 fill down, a small half-zip, a slimmer width, and a small hood. Even with the smaller dimensions I find that the bag is comfortable. And the smaller size leaves less dead air to warm with body heat.
Hyperion 20 Features
Shell: Lightweight and thin 10-denier nylon ripstop with a durable water repellent coating. Ten denier is a thin fabric shell, but I have found that it holds up if given care and attention.
Insulation: The Hyperion uses 900 fill Nikwax hydrophobic goose down that Therm-a-Rest says dries three times faster than untreated down, absorbs 90% less water, and maintains loft 60 times longer than untreated down.
Box Baffles: The Hyperion uses box baffles—lightweight material placed between the shell and liner to form a box—that eliminate gaps that could create cold spots.
Draft Collar, Draft Tube: The draft collar snugged tight across my forehead and neck prevent cold air from getting inside the bag, and a draft tube runs the length of the side zipper.
Hood: Small. I can’t fit my inflatable pillow inside the hood, and use my backpack laid flat under the bag as a pillow. A drawcord on the right side (when lying on my back in the bag) tightens the hood around my face and shoulders. A snap keeps the hood closed and the zipper from sliding down.
Warmth: I slept comfortably while wearing lightweight thermal pants and shirt when the temperature was about 30, and began feeling the cold when the temperature dropped to 25F. Any lower and I would have put on a midweight shirt. That jibes with the Hyperion’s EN lower temperature limit of 20F, the temperature at which a warm sleeper (though not me) might still sleep comfortably. The comfort level is 32F, and the EN extreme limit is -9F.
SynergyLink Connectors: I am sold on these straps that hold the Hyperion flat to my air pad. And they are important to use because 70% of the Hyperion’s insulation is on the top and sides, while 30% is on the bottom. Does this mean you have to be a back sleeper to use the Hyperion and the straps? Not in my experience. I still toss and turn inside the Hyperion while the straps keep the bag stable and flat on my air pad.
Stuff Pocket: There’s no pocket in the bag to hold a phone or other temperature-sensitive gear, presumably to save weight. I put my phone and headlamp inside the bag when it’s cold at night.
Zipper: The half zip changes the way I get in and out of the bag. I slide in from the top, rather than rolling in as I do with a three-quarter-length zipper. The zipper is small and has inner and outer string pulls, and slides easily without snagging. The two-way zipper provides ventilation at the midpoint of the bag.
Fit: The unisex Hyperion cuts ounces with a slimmer profile, which also means there’s less empty space for your body to heat. I’m 5 feet, 10 inches, and weigh 160 pounds, and find that the 57-inch shoulder girth is good for me, but if you’re about my height and much heavier, you might consider a long bag with a wider 58-inch girth. The bag is very slim from the knees down, but with enough room that my legs and feet aren’t pinched. The Hyperion’s slim fit does not leave room for storing clothes inside at night.
Stuff Sacks: The storage stuff sack is large enough to hold the Hyperion without compressing it, and the bag has a hang loop, which is my preferred way of storing sleeping bags. The compression sack gets the Hyperion down to a small size.
Warranty: Therm-a-Rest will repair or replace gear found to be defective within the first two years of purchase. Sleeping bags are covered under the Better Sleep Guarantee, which means that if you are not completely satisfied with your bag, return it within three months with the original receipt of purchase for a full refund. No questions asked.
Hyperion 20 Pros
Weight: 1 pound, 4 ounces for a regular length. It’s hard to find another 20F down bag at this weight. The 900 fill down is warmer per square ounce than 800 or 700 down down fill, which is one of the factors in the Hyperion’s low weight.
Warmth: I’m warm sleeping to about 30F in the Hyperion, but begin to chill at 25F unless I put on extra clothing.
Zipper: Although the zipper is small, it slides easily without snagging.
Sleeping Pad Straps: I’m sold on the removable straps that connect the sleeping bag to the pad, ending my sometimes nightlong struggles to stay on the pad. Plus they keep the underside of the bag, which has less insulation, flat against my insulated air pad.
Easy Hood Drawcord: I like the single cord that draws the hood and neck draft tube close to my head, rather than struggling with one cord for the neck draft tube and another for the hood.
Hyperion 20 Cons
Small Hood: This is my biggest con. I can’t fit my inflatable pillow inside the hood, so I use my backpack as an outside pillow, stuffing my inflatable pillow inside the front mesh pocket.
No Stuff Pocket: I usually keep my phone within reach inside my sleeping bag, so the lack of a stuff pocket doesn’t bother me. But it’s a feature some people might miss.
Zipper: I’ve had to adjust to sliding in and out from the top of the bag because of the half zip, rather than rolling out with a three-quarter zip. But it’s an adjustment I’ve easily made.
Rough for Side Sleepers: Less insulation on the bottom of the Hyperion means that side sleepers expose their backs to cold air. I attach the Synergy Link Connectors to my air pad and toss from side to side inside the bag while it stays flat on the pad.
Overall Value
At $549.95 for the regular size, the Hyperion’s price is on the higher end for a three-season sleeping bag. It’s a comfortable, well-made sleeping bag that has ultralighters in mind: weight-saving 900 fill down, a slim cut, a half zip, and no stuff pocket. So if shedding weight without giving up comfort is your goal, the Hyperion is a good choice for a sleeping bag.
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This product was donated for purpose of review.
