Therm-a-Relaxation Hyperion 20 Sleeping Bag Overview

Therm-a-Rest Hyperion 20 Sleeping Bag Review

The Therm-a-Relaxation Hyperion 20 is an ultralight down sleeping bag designed for again sleepers that weighs 20 ounces (1 lb 4 oz) and is insulated with 900 fill energy waterproof down. It has a box-baffled building to remove chilly spots and a half-length zipper to save lots of weight. When stuffed the Hyperion 20 packs down to only 3L making it excellent for journeys the place pack area is at a premium. The insulation is zoned with 70% on prime and 30%, leveraging your sleeping pad insulation for heat. What’s the catch? It has a tapered reduce with restricted girth, however if you happen to can match inside comfortably, it’s a candy ultralight sleeping bag.

RELATED: 10 Finest Down Sleeping Luggage for Backpacking

Specs at a Look

  • Gender: Unisex
  • Weight: 20 oz (1 lb 4 oz) – Measurement Medium, Size 72″
  • Fill Weight: 12.5 oz
  • Sizes: S, M, L
  • Sort: Mummy
  • Packed Measurement: 3L
  • EN Consolation Temperature Ranking: 32F (-6C)
  • EN Restrict Temperature Ranking: 20F (-23C)
  • Building: Field Baffled
  • Girth/Hips/Footbox (dimension common): 57″, 49.5″, 43″
  • Insulation: 900 Fill Goose Nikwax Hydrophobic Down RDS
  • Zipper: Half-Zipper
  • Zipper Facet: Left
  • Draft Tube: Sure
  • Shell/Liner Cloth: 10D Nylon RipStop with DWR / 10D Nylon RipStop
  • Stuff Sack: Compression sack included and a material storage bag
  • Go to Therm-a-Relaxation for full Specs

Zoned Insulation

The Hyperion 20 sleeping bag is a backpacking and mountaineering mummy-style sleeping bag designed for again sleepers. I can’t emphasize the latter extra. The insulation is distributed in a zonal vogue with 70% on prime and 30% beneath you, leveraging the chilly resistance of your sleeping pad to maintain you heat. When you roll over onto your aspect, you’ll sleep a lot colder than if you happen to sleep in your again with the majority of the goose-down insulation on prime of your torso. To stop this, the Hyperion 20 comes with non-obligatory sleeping pad straps that connect with loops on the again of the bag. These act equally to quilt-pad attachment straps to maintain you in your sleeping pad at evening.

Optional pad straps can keep you on your pad.
Non-obligatory pad straps can preserve you in your pad.

Ultralight Design Options

At simply 20 oz, how did Therm-a-Relaxation make this sleeping bag so light-weight?

The bag is heavily tapered and fits snug to reduce weight
The bag is closely tapered and matches cosy to cut back weight

First off, the sleeping bag is kind of tapered and is designed to fit your needs with out loads of additional inside area. I can match into its 57″ shoulder girth (dimension common) however there isn’t a complete lot of additional room for me inside from my waist up. The footbox is moderately spacious, nonetheless, and my ft can simply splay aside comfortably.

The Hyperion is insulated with 900 fill energy Nikwax waterproof goose down which is premium stuff when it comes to warmth-to-weight ratio. Increased fill energy down like this offers extra heat by weight than decrease fill energy down and is used to save lots of weight.

Whereas the Hyperion 20 has a two-way zipper, it’s solely half-length, so it ends at my knees: this protects weight by eliminating the necessity for an extended zipper, draft tube, and anti-snag taping, which might be discovered on the higher half of the zipper. The 2-way zipper makes it potential to vent the bag to a sure extent, though not within the footbox. When you get habitually sizzling ft or you might want to camp in extremely popular/humid climate, I’d get a unique sleeping bag with a full-length zipper as an alternative.

The draft tube is covered with a piece of grosgrain to prevent zipper snags.
The draft tube is roofed with a bit of grosgrain to forestall zipper snags.

The light-weight 10d ripstop nylon material on the Hyperion is considerably delicate and also you’ll need to deal with it gently to forestall it from tearing. The anti-snag tape alongside the zipper draft tube helps forestall rips, however you’ll need to watch out with it however.

The hood is a fairly commonplace mummy hood with a right-side management to allow you to cinch the hood closed. It doesn’t have area for a pillow or something, however it’ll transfer with you if you happen to roll over like a jacket. A snap on the prime of the aspect zipper helps seal the hood on the left aspect and preserve its form even when the aspect zipper isn’t absolutely closed.

This snap takes pressure off the zipper and helps maintain the hood’s shape.
This snap takes stress off the zipper and helps preserve the hood’s form.


The Therm-a-Relaxation Hyperion 20 is an ultralight sleeping bag designed for again sleepers preferring the draft-free efficiency of a sleeping bag over a backpacking quilt. Weighing 1 lb 4 oz, it’s optimized for backpacking journeys the place area and weight are a premium. It’s by far one of many lightest sleeping out there at the moment but it surely’s a comfortable match, more durable to vent, and greatest utilized in cooler temperatures moderately than sizzling and humid ones. A 32-degree mannequin can be out there.

Disclosure: Therm-a-Relaxation donated a sleeping bag for evaluate.

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Final up to date: 2023-04-28 01:15:01

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