GEAR REVIEW: Therm-a-Rest Hyperion 20 Sleeping Bag

By Will Rietveld

In spring 2019, Therm-a-Rest, a division of Cascade Designs, introduced some seriously lightweight and technically advanced gear. The Hyperion 20 sleeping bag (and its companion Hyperion 32) is in that suite.

I tested the Hyperion 20 for summer backpacking. I previously used and recommended a 30F bag for summer backpacking, but as I get older I get colder and prefer a 20F rated bag. I also prefer a bag with enough shoulder girth to wear at least an ultralight insulated jacket inside to increase bag warmth when needed. So how did the Hyperion 20 meet those needs?

The Therm-a-Rest Hyperion 20 sleeping bag, new for spring 2019, features 900 fill-power Nikwax water-resistant down for warmth, a half-length zipper, and lightweight materials throughout to achieve a weight of just 20 ounces for size Regular.

Specifications and Features

Manufacturer	Cascade Designs (www.cascadedesigns.com)
Model	Therm-a-Rest Hyperion 20 Sleeping Bag
Temperature Rating	20F (EN tested to 32F Comfort, 20F Transition, -9F Risk Range
Sizes Available	Small, Regular, Long (size Regular Tested)
Bag Girth	Shoulder 57 in, hip 49.5 in, foot 43 in (size Regular)
Shell Fabric	10D nylon ripstop (shell and lining, DWR on shell)
Insulation	13 oz of 900 fill-power down (size Regular)
Weight	20 oz, measured weight 20.5 ounces
Features	Box baffled construction, zoned insulation, single pull half-length zipper with inside and outside pull loops and a tab and snap at the top, zipper baffle and hood rim baffle, 2 removable stretch pad straps on the bottomside, stuff sack and cloth storage bag included
MSRP	Small $390, Regular $410, Long $430

Description

When I first saw the Hyperion 20 at the summer 2018 Outdoor Retailer trade show, it featured TARs ThermaCapture technology, which is a thin heat-reflective film inside similar to that used in their NeoAir sleeping pads. However, it was later dropped due to “manufacturing and environmental reasons”. I was hoping to test that technology, it could have made a significant difference, but there were certain concerns about toxic fumes inside the bag. However, 13 ounces of 900 fill-power hydrophobic down is about right for a 20F rated sleeping bag without ThermaCapture.

The bag' s box baffled construction is basically thin mesh (think mosquito netting) baffles shaping and separating the down chambers. And the zoned insulation means that 70% of the down is on the top and sides and 30% is on the bottom. Down on the bottomside gets compressed, and presumably a sleeping pad provides supplemental insulation.

I note that the temperature rating implied for this bag is 20F, which suggests it’s comfortable at 20F. That’s not quite true; the EN test says that its comfortable at 32F, the end of comfort arrives at 20F, and at -9F your life is in danger.

Sleeping bag warmth ratings and sleeper warmth is complex, and a disclaimer is often provided. The equation consists of factors like the amount and fill-power of the down, bag girth (a slimmer bag is warmer), and bag construction. A bag’s warmth rating is just one factor to evaluate it; other useful factors are the bag’s fill weight (13 ounces for Size Regular), double layer loft (4.5 inches in this case), and shoulder girth (the specification for the Hyperion in size Regular is 57 inches, but we measured it at 58.5 inches). And, of course, people vary in how well they stay warm.

For me, the red flag on this bag is its specified 57-inch shoulder girth. That data was not available when I received the bag, but I assumed it was similar to other TAR bags, like the Parsec 20 which is 62 inches. Ultralight backpackers like me will love the bag’s 20 ounce weight, but the tight shoulder girth may limit wearing any insulating clothing inside (see field testing section).

The Hyperion’s 10-denier shell and lining fabric is a good weight saver; it’s hard to go much lighter than that. Also its half-length single-pull zipper (it looks like a #3) saves a little weight. Single-pull means it’s sewn in at the bottom, has only one slider, and won’t separate.

Overall, TAR has done a diligent job of trimming weight and maximizing warmth of the Hyperion 20.

Field Testing

I tested the Therm-a-Rest Hyperion 20 on seven trips: one spring car camping trip in the Southern Utah backcountry and six backpacking trips in the Southern Colorado Rockies. The lowest temperature encountered was 34F. I slept under the stars, in 3-person double-wall tent, in a 1-person floorless Dyneema shelter (shown), and in a 1-person silnylon single-wall tent.

In spite of the bag’s slender shoulder girth, I initially tried sleeping in the bag wearing a full complement of UL camp clothing (thin baselayer + ultralight synthetic insulated jacket + ultralight down jacket.) The jackets were not as bulky as they might sound, weighing 6 ounces and 5.9 ounces, respectively. With those clothing items worn, I found it very difficult to completely zip up the bag, and it was necessary to snap the tab at the top of the zipper to keep it from opening on its own. I’m 6 feet tall and the bag (rated to 6 feet) just barely fit my length.

Next I tested the bag wearing only a thin baselayer and the ultralight down jacket described above, and that made a remarkable difference – the bag felt much roomier inside and the zipper was fairly easy to fully close and secure with the tap and snap. I wore that clothing combination (thin merino baselayer plus Montbell Plasma 1000 down jacket) inside the bag on my next five backpacking trips.

Note that the zipper curves at the top to the base of the hood. When the bag is tighter, as with wearing too much clothing inside, the zipper is hard to operate and snags more because of the tension on the zipper. I got along with the small zipper and its two cordloop pulls a lot better when I wore minimal insulated clothing inside.

As far as bag warmth, I stayed warm in the Hyperion 20 down to 34F one night, and numerous nights in the 40sF, but I was not able to test the bag’s 20F lower limit during my testing. The bag’s fill weight of 13 ounces of 900 fill-power down is about right for a 20F bag rating, so the Hyperion 20 is on target with comparable bags. A simple method to compare bags with different down fill-power is to multiply the fill weight by the fill-power to get the total down volume in cubic inches.

I found the bag’s removable pad straps on its bottomside handy for helping to hold a sleeping pad in place, especially a slippery one like the Therm-a-RestNeoAir Uberlite I co-tested with the Hyperion. If they are not needed they are easily removed to save a smidgeon of weight. Note that using the pad straps conflicts with side sleeping.

The bag’s hood adjustment is a one cord design with an external cord loop and anchored cordlock. Pull on one side of the loop to snug one side of the hood; pull on the other side of the cord loop to snug the other side of the hood.

Assessment

Overall I found the Therm-a-Rest Hyperion 20 quite liveable and warm, despite its slender shoulder girth. Fortunately the measured shoulder girth (58.5 inches) was a little roomier than the specified shoulder girth (57 inches), and that relatively small amount made a big difference. The Hyperion works for me if I limit clothing inside to a thin baselayer plus a thin ultralight jacket. That allows me to get the zipper closed without much snagging and the top tab snapped to keep it zipped. Legwear is a lesser issue regarding room inside the bag. This basically makes the Hyperion 20 a summer bag for mountain backpacking; it likely will be chilly in the shoulder seasons.

Readers might be wondering what the circumference of my upper body is so they can evaluate their fit in this bag; I’m 44 inches around my upper arms wearing a thin baselayer, and 47.5 inches wearing the baselayer plus a thin down jacket. My advice is to measure your shoulder circumference wearing similar clothing before you consider the Hyperion. If you are at or below my dimensions, you are good; if you are larger or prefer to wear more clothing inside your sleeping bag, look for a roomier bag. Or consider getting the Hyperion size Long to get an extra inch of shoulder girth.

The MSRP of $410 for the Hyperion 20 Regular length is a good value for a 900 fill-power down insulated ultralight sleeping bag. And its 20-ounce weight is hard to beat – 13 ounces of down and 7 ounces of other materials – it’s the same weight as many ultralight 30F down sleeping bags.

Overall, Therm-a-Rest is solidly into the ultralight down sleeping bag market with the Hyperion 20 being a good choice at 20 ounces for a 20F down bag. Interestingly, Therm-a-Rest has a Better Sleep Guarantee, which they describe as “All Therm-a-Rest sleeping bags and quilts are covered by our Better Sleep Guarantee. When you wake up on a Therm-a-Rest sleeping bag or quilt, we're confident you'll wake up feeling better than ever. If you are not completely satisfied, return it within three months with the original receipt of purchase and we will give you a full refund- no questions asked.” They stand behind their bags!

GEAR REVIEW: Therm-A-Rest NeoAir Uberlite Air Mattress

By Will Rietveld

I was talking with a friend the other day and we reminisced to 20 years ago when there was very little ultralight backpacking gear available for purchase and many of us made our own. A “lightweight” sleeping pad at that time (often labeled “ultralight”) weighed a pound. Fast forward to the present and we now have the Therm-a-Rest Uberlite pad that weighs just 6 ounces in Size Short, 8.8 ounces in size Regular, and the luxurious Large at 12 ounces. All are thick and comfy, and have a sufficient R-2 rating for summer use.

What’s not to like? Well, it’s mostly all positives, but there is one significant problem that I point out in this review, along with a solution. Read on, or skip to the bottom.

The new Therm-a-Rest Uberlite Pad comes in sizes Short (shown), Regular, and Large. It’s currently the lightest inflatable sleeping pad on the market.

Specifications and Features

Manufacturer	Cascade Designs (www.cascadedesigns.com)
Product	Therm-a-Rest Uberlite Sleeping Pad
Sizes	Small, Regular, Large
Dimensions	Small is 20 in wide x 47 in long x 2.5 in thick; Regular is 20 x 72 x 2.5, Large is 25 x 77 x 2.5
Weight	Small is 6 oz (5.4 on my scale), Regular is 8.8 oz (8.9 on my scale), and Large is 12 oz (not tested)
Fabric	Top is 15D ripstop nylon, bottom is 15D nylon
MSRP	Small $140, Regular $180, Large $210

Description

By eliminating the heat-reflecting coating on the internal baffles and adopting lighter fabrics, Therm-a-Rest (TAR) has squeezed some weight out of their NeoAir pad line, making them now truly ultralight. For a size Regular pad, the weight drops 3.2 ounces compared to their XLite pad (see comparative specs in the table below). While some features are also diminished (which I will get to in a minute), comfort is not one of them. This approach works for me, mainly because I value light weight over features.

	Uberlite (Regular)	XLite (Regular)
Fabric	15 denier	30 denier
Weight	8.8 ounces	12 ounces
R-value	2	3.2
Cost	$180	$170

The triangular baffle construction inside the pad is the same as previous NeoAir pads, but the heat-reflective ThermaCapture coating is eliminated, resulting in a pad that is equal in physical comfort, but losing some insulation (R-value is 2.0 compared to 3.2 for the XLite), and happily the annoying nosiness of previous versions of the NeoAir. The lighter fabric means less durability (the Uberlite is 15 denier and XLite is 30 denier). The lower R-value of the Uberlite means it is intended for summertime use. I might add that the XLite pads are still available, and some hikers may prefer them because they are warmer and more durable.

Field Testing

Testing the Therm-a-Rest Uberlite sleeping pad in the Southern Colorado Rockies. Size Regular shown. 

I received the size Regular Uberlite pad in January, and size Short in May, so I couldn’t get in any mountain testing until June. My testing consisted of one spring car camping trip in the Southern Utah Canyonlands country in a 3-person tent, 6 backpacking trips in the Southern Colorado Rockies sleeping on a plastic groundsheet in a floorless Dyneema shelter, and one volunteer trip in Utah’s La Sal mountains sleeping several nights in a 1-person silnylon tent with silicone stripes painted on the floor. Following are my testing results by attribute:

Ease of Inflation – The Uberlite inflates quickly by mouth; about 12 lungfulls for the size Regular pad. The pad has an antimicrobial treatment on the interior to prevent mold forming inside.

Sizing – I found the Short and Regular pads’ width of 20 inches to be adequately wide. That’s the “standard” width for a size Regular pad. I’m a side sleeper, and find I need to adjust my hip position when I turn over, but that’s not a problem. For those who require or prefer more width or length, a size Large pad is available with 25 inches of width and an extra 5 inches of length.

Comfort – Excellent, as expected. It’s hard not to be comfortable on a 2.5-inch inflated pad. I found the pad most comfortable when it’s inflated a little less than full. Three sizes are available to meet body size and preferences. The size Short still has the “dropoff” issue at the foot end, but that is remedied by putting something under your feet or curling up.

Warmth – As mentioned, the R-value has gone down to 2.0, which is minimal. I found it to be warm in my testing, where temps typically dropped into the low 40s F and one night at 34F, but it could be chilly below that, which I did not test. It may not be warm enough for some people, but I have a remedy for that later in this review.

Noisiness – Gone.

Durability – On my first backpacking trip with the Uberlite pad I camped in a grove of spruce trees on smooth ground covered with spruce needles. I slept in a floorless  Dyneema shelter and used a thin plastic Gossamer Gear Polycro groundsheet under the pad. You guessed it; the pad was punctured by a spruce needle on my first backpacking trip with it. The patching kit that comes with the pad is convenient and works perfectly: clean the spot with a provided alcohol swab and let it dry, compress a glue dot around the hole, and cover that with a Type A patch.

Patched puncture from a spruce needle. The smashed glue dot (circle) probably wasn't necessary for a small puncture, but I used it anyway to try it out. The dot in the center is my mark of the hole's location, not the hole itself.

Pricing – The Uberlite is pricey: $140, $180, and $210 for sizes Small, Regular, and Large, respectively. Each size costs $10 more than the XLite, so we are reminded that ultralight gear costs more for less weight. Ah well, you put your money (if you have it) where your passion is!

Slip-Resistance – I saved this attribute for last because it is where the problem lies that I alluded to earlier. The Uberlite basically doesn’t have any slip-resistance. The first time I tested the size Regular pad was a car camping trip in the Southern Utah backcountry, sleeping in a 3-person double-wall tent on a slight incline. The pad was like sleeping on a water slide; I chased it all over the floor of the tent trying to stay on top of it! I had the same experience sleeping on a thin plastic groundsheet while backpacking, and finally resorted to sleeping with the pad directly on the ground (no damage done, but not recommended).

The first solution I tried was the silnylon tent with silicone stripes painted on the floor, which is standard procedure for overcoming the slipperiness of silnylon. It didn’t work; I still slid around the tent floor. I also tried painting stripes of diluted silicone on my plastic ground sheet, and the pad itself; no success. The silicone easily rubbed off the slick nylon surface of the pad.

I tried painted diluted silicone on the bottomside of the pad to provide some slip resistance. It readily rubbed off and did not keep the pad from sliding around.

On a trip where I slept in a 1-person silnylon tent, I took along a piece of “non-skid rug pad” (used to keep rugs from creeping) to try another solution. It worked, but the rubbery rug pad is too heavy for backpacking, especially if you take a full pad length of it.

Next I tried a Gossamer Gear Thinlight pad, which is a full-length one-eighth inch thick closed-cell Evazote foam pad weighing just 2.5 ounces. That worked perfectly; the Uberlite didn’t budge on the bottomside.

But that solves only half the problem; a smooth nylon-shelled sleeping bag also slides on top of the Uberlite. Note that some sleeping bags’ shell fabric is more slip-resistant, and quilt users are less likely to have a problem with top sliding. And one could also use a Thinlight pad on both sides of the Uberlite.

I came up with this approach to provide slip-resistance to BOTH sides of the Uberlite pad using one Gossamer Gear Thinlight pad. Simply wrap the Thinlight pad around the Uberlite pad so the ends of the Thinlight are on the bottomside, and use pad straps on a sleeping bag (the Therm-a-Rest Hyperion 20 in this case, which I co-reviewed with the pad) to hold the Thinlight pad in place. This places the Thinlight under my hip, where maximum compression holds it and the sleeping pad in place. However, the Thinlight pad only provides extra puncture protection in that location. I found the wrapped Thinlight pad stays in place very well without the pad straps; the important point is to have the overlapping ends of the pad on the bottomside.

I like the Gossamer Gear Thinlight pad solution best, because the Thinlight is a multi-purpose piece of gear: it adds insulation to the Uberlight pad, protects it from punctures, can be used as backpanel padding in a pack with a pad sleeve, and serves as a sit or nap pad or camp seat.

Assessment

The Therm-a-Rest Uberlite pad is a welcome addition to my ultralight gear kit, allowing me to cut a few more ounces. Granted, the Gossamer Gear Thinlight pad I take when using the Uberlight pad can offset the weight savings, but when I use a pack with a pad sleeve I can insert the Thinlight instead of other padding. I also like the extra utility of the Thinlight, as mentioned above.

Eventually, perhaps, Cascade Designs will fix the slipperiness issue of the Uberlite pad, and a user corrective measure won’t be needed. Other than the lack of slip-resistance, I am impressed with the quality, light weight, and comfort of the Uberlite pad.

It’s interesting to note that other reviewers focused more on the Uberlite’s elimination of the annoying “crinkly” sound characteristic of earlier versions of the NeoAir pad. The noisiness of the NeoAir really bothered a lot of people. I didn’t find it to be a problem, but I’m half deaf, so that’s one advantage of hearing loss. They hardly mentioned the slipperiness issue, but I consider it to be a significant problem that can confound one’s happiness in the wilderness.

Another issue with the Uberlite that deserves some cautionary commentary is its reduced durability. Yes, nylon is highly resistant to abrasion, but it is susceptible to puncturing or cutting. Thus the Uberlite, as with most ultralight gear, requires careful use. If you are hard on gear, the more durable TAR XLite pad might be a better choice. I like the combination of the Uberlite plus a Gossamer Gear Thinlight pad because the Thinlight provides slip-resistance, puncture-resistance, and extra insulation.

Bottom line, I give the Therm-a-Rest NeoAir Uberlite sleeping pad a thumbs up, with the caveat that you will likely have to remedy its lack of slip-resistance. If you come up with another good solution post it below.