Therm-a-Rest Hyperion 20 Degree Sleeping Bag is ideal for backpackers and hikers because of its incredible weight and packed size. It is EN tested and with the top-notch down insulation.
Key features
- Extremely packable.
- Top-quality 900 down fill.
- Ultra-lightweight.
- EN rated.
- 3 Sizes to choose from.
- Zoned insulation.
What this is about
So this is a new sleeping bag which Therm-a-Rest launched for 2019, a typical mummy-style bag with minimal features to reduce the weight. It is among the lightest bags on the market for this temperature rate, in fact this is an ultra-light item. This is mainly because of its top quality 900-fill Nikwax Hydrophobic Down.
So this is a treated down which:
- Maintains its loft 60 times longer than an untreated down.
- Absorbs 90% less water than an untreated down.
- Dries 3 times faster.
These strong statements are from the manufacturer. Note that this is Responsible Down Standard Certified item, and this ensures a humane treatment in the down supply chain.
The temperature rating
The official rating for this Hyperion sleeping bag is 20 F(-6 C). You will see more details in the specifications below. I know that for many people this is important to stress: it is with EN rating (more below). So this should put your mind at ease and you know that you have a reliable item. But as always, the feeling of cold and warm is individual, and such ratings are for an ‘average’ user.
Note that they have yet another bag in this series the Therm-a-Rest Hyperion Sleeping Bag 32 Degree; so this is 0-degree on the Celsius scale.
The construction
Here you have what they call the Box Baffled Construction, and this implies mesh inner walls to maximize loft and minimize cold spots in key areas. So there is no stitching that goes all the way from one side to the other:
You also have what they call Zoned Insulation: This means 70% of it is on the top and only 30% on the bottom. This saves the weight, and the reason is the following. The insulation pressed by your body loses most of its insulating properties in any case, this is why you have to rely on your sleeping pad which should have the appropriate R-value (or temperature rating).
SynergyLink Connectors: This term implies straps underneath the bag which should keep the pad in place, see the picture. They are removable for versatility.
I must say that these straps are not good enough for somebody like me who turns a lot during sleep. I find the design of sleeves in these Big Agnes Lost Dog bags better.
The fabric
The shell is incredibly thin 10D Nylon RipStop with DWR, and the liner fabric is the same material. The zipper is on the left, and the hood is with the usual cinch cord, see the picture below. You have a draft collar along the zipper. The picture below shows how fluffy and comfortable this Hyperion 20 bag looks.
Please see a bit more in this short video:
Who is it for
Size-wise, they build it in three sizes Small (S), Regular (R), Long (L), and those cover quite a big range of length 73-85 inches (185-216 cm). So the bag is unisex and the smaller sizes are suitable for most women. But if you would rather have a women-specific sleeping bag, please check our separate list with best sleeping bags for women.
Seasons-wise, with the 20 F (-6 C) rating, this is a true 3-season sleeping bag. But this will depend on the activity. What I mean by this is that if this is about ordinary summer camping, you would perhaps rather go for a bigger rectangular sleeping bag and you would not need such a rating. But if you move from place to place and expect a variety of weather conditions, then this would be the right option.
Weight-wise, well, you will not find many lighter sleeping bags for such a temperature rating. The R size weighs only 1 lb 4 oz (0.58 kg), and the fill is 13 oz (0.35 kg) so this is an ultra-lightweight sleeping bag. You will see below in the comparison table how it stands when compared with some top items on the market.
When you combine this with its excellent packed size which is only 8 x 6 inches (20 x 15 cm), see below, you realize that you have an excellent option for any use where the weight and packed size should be minimal. This means for backpacking, hiking, climbing, mountaineering, biking tours, etc.
Specifications
- Type: mummy sleeping bag.
- Sizes: Small (S), Regular (R), Long (L).
- EN rated.
- EN temperature limits:
– Comfort: 32 F (0 C).
– Limit: 20 F (-6 C).
– Extreme: -9 F (-23 C). - Weight:
– S: 1 lb 3 oz (0.55 kg).
– R: 1 lb 4 oz (0.58 kg).
– L: 1 lb 6 oz (0.63 kg). - Fill weight:
– S: 11.5 oz (0.34 kg).
– R: 13 oz (0.35 kg).
– L: 14 oz (0.39 kg). - Packed size: 8 x 6 in (20 x 15 cm).
- Size:
– S: 73 x 27.5 in (185 x 70 cm).
– R: 80 x 28.5 in (203 x 72 cm).
– L: 85 x 29 in (216 x 74 cm). - Height fit (S/R/L): 66/72/78 in (168/183/198 cm).
- Girth (shoulders/hips/feet):
– S: 55/48.5/40 (140/123/102 cm).
– R: 57/49.5/43 (145/126/109 cm).
– L: 58/51/46 (147/130/117 cm). - Compression sack included.
- Storage sack included.
Therm-a-Rest Hyperion 20 Degree Sleeping Bag vs Competitors
It is not enough to state that a bag is ultralight and ultra-packable, the best way to understand the meaning of these terms is to put is side by side with some other bags of the same type and compare. So here in the table, it is given together with two other bags that are the top items in this industry, the Big Agnes Hitchens 20 and Big Agnes Mystic UL 15 sleeping bags.
As you realize, it is much lighter but the other two are a bit more compact when packed (in theory, because they come without a compression sack so you have to buy it separately). It is also far more affordable than the Hitchens 20 bag. Please follow the links for more detail.
Weight lb (kg)
Packed size in (cm)
Sizes
EN rated
Temperature F(C)
Fill
Compression sack
Price
Therm-a-rest
hyperion
1.28 (0.58)
8 x 6
(20 x 15)
3
yes
20 (-7)
900 down
yes
$$$
big agnes
hitchens
1.69 (0.76)
7 x 6
(18 x 15)
3
yes
20 (-7)
850 down
no
$$$$
big agnes
mystic
2 (0.91)
7 x 6
(18 x 15)
3
no
15 (-9)
850 down
no
$$$
Final thoughts, rating, pros & cons
If you need an ultra-packable and ultra-lightweight sleeping bag, and you are willing to pay for it, then this Therm-A-Rest Hyperion 20 UL Sleeping Bag is what you need. This is the top in the industry, you have seen several certifications about the rating and production of this bag, and the brand behind this item is renown globally. So you know what you are buying. I have included it in my list of best compact sleeping bags for backpacking.
The price of this Therm-a-Rest Hyperion 20 sleeping bag depends on the size. In any case, it is far from an affordable item, but you have seen its weight and packed size; such features have a price. Please see how I rate it against my standard set of parameters used for all the sleeping bags in the site for an easy comparison:
Therm-a-Rest Hyperion 20-Degree Ultralight Down Mummy Sleeping Bag Long
Pros
- Incredible weight.
- Great packed size.
- Top-quality fill.
- Compression sack included.
- RDS certified.
- EN rated.
Cons
- Very expensive.
Please visit my page with sleeping bags if you need more options to check.
Note that this is not a sponsored text, and I have no business relationship with this brand. What do you think about this sleeping bag? Please share your thoughts, there is a comment box below.
Chris Pettiet says
Hello,
I bought a Therm-a-rest Hyperion 20 partly based on your review. I purchased the sleeping bag in the middle of June for my thru-hike on the JMT. I was on-trail for 16 days (roughly July 17th to August 1st).
1.) I had a zipper snag on the first night that caused a puncture on the inside of the bag. I was able to get the sleeping bag material out of the zipper and then patch the bag with a piece of duct tape.
2.) Two nights later, the zipper snagged again in the middle of the might while I was zipping the bag up from the inside as the temperature dropped as the night progressed. This time, I wasn’t as lucky as I wasn’t able to get the zipper unstuck and the zipper actually came off of the bag and caused another hole in the bag.
3.) Since the bag is narrow, a zipper fail is essentially catastrophic as heat easily escapes and a viable seal using safety pins isn’t something that worked effectively enough to keep me warm when temperatures dipped into the low 40’s at higher elevations overnight.
4.) The other issue with the bag was the material on inside top of the bag, where the mummy bag fits over your head, was essentially worn out after sixteen nights of use!
I sent the bag back to Cascade Designs and explained to them what had happened and asked them if the bag could be repaired or replaced since the bag was less than 90 days old. Almost a month passed and I never heard back from them.
The stated policy on the website is they will evaluate the bag and reach out via email or phone to let the customer know whether or not the bag is repairable, repairable for a fee, replaceable under warranty, or not reparable at all under warranty.
I sent another follow up email, didn’t receive a reply to that email, and then received an email about a week later (this was after almost a month after I sent the bag to them) that stated my repair had been completed along with a tracking number. When I received the sleeping bag, the box contained a note saying the bag couldn’t be repaired and listed an address of a company that provides repairs. Also, they placed a yellow patch on the bottom of the bag where it looks like they had punctured the bottom of the bag!! Keep in mind the issues with the bag were the zipper coming off, two internal punctures I had patched with duct tape, and the wear on the inside of the mummy hood. I was astonished to see the warranty department had damaged the bag!!
I followed up with the warranty/repair department via phone and spoke with a customer service representative who essentially said my warranty claim was being denied due “excessive use!”
I wanted to make you aware of my experience with this bag because I feel this sleeping bag isn’t designed or constructed with materials that ca withstand regular use over multi-day backpacking trips. Also, buyers should be prepared to be denied a warranty claim even if the timeframe is with 90 days.
Thank you,
Chris Pettiet
Jovo says
Hi Chris, many thanks for this first-hand information and sorry to hear about such issues with the bag. It is a shame really that they acted the way you are describing. It is very bad for their reputation when our readers see this, I would say this is a shortsighted policy of this brand. Pity that they do not realize this.