Therm-a-Rest Hyperion 20
Rating
Versatility: 5
Size/Weight: 10
Features: 9
Construction: 9
Sleep Quality: 6
OVERALL: 7.8
Featherlight champion.
Tipping the scales at just 1 pound 4 ounces, the Therm-a-Rest Hyperion is unbelievably light for such a well-made sleeping bag. Designed specifically to shed weight for multi-day treks, this does come with some trade-offs. You'll find it's not quite as warm as bulkier options, has a snug fit, features only a partial zipper and carries a premium price, but if compact packing is your top priority, nothing beats this.
Best For: Extended backpacking adventures
Pros: Remarkably lightweight, built to last
Cons: Snug interior, less insulation than others
Verdict: The ultimate sleeping bag for serious distance hikers
Skip ahead to First Impressions, Sleeping Experience, Features Analysis, Construction and Durability, or the Final Verdict, check out how the Therm-a-Rest Hyperion 20 compares to others in our list of the Top 5 Sleeping Bags.
Specs:
Packed Size: 6x8in
Weight: 1lb 4oz
Fill: 900-Fill Nikwax goose down
Approx Price: $599.95
First Impressions
We tested this -6°F mummy bag expecting something lightweight and compact, and it delivered on both counts.
The Therm-a-Rest Hyperion uses 900-fill water-resistant down (absorbs 90% less moisture), has special connectors to attach to sleeping pads, targeted insulation zones and weighs just 20oz while packing down to a tiny 6x8 inches.
Right away, we could tell this would be perfect for multi-day hikes in moderate conditions.
Sleeping Experience
To cut weight, this bag uses uneven insulation (70% on top/sides, 30% underneath). This made it less warm than we hoped, especially against cold ground, even with a quality sleeping pad.
The nylon exterior feels nice, but the slim fit makes moving around harder than other bags we've tried.
Features Analysis
Several smart details set the Hyperion apart. The materials and design let it compress easily without struggling with straps.
We appreciated the option to connect it to a sleeping pad (Therm-a-Rest makes great ones). The smooth zipper with wind barrier and adjustable hood worked perfectly, overall, impressive features.
Construction and Durability
Therm-a-Rest knows their stuff. The construction meets expectations for the price, using durable materials that should hold up over time.
Final Verdict
With better warmth and more room, this could be a top-tier sleeping bag. What really shines is its featherlight weight and compact size. For backpackers covering long distances in decent weather, it's a fantastic option that won't weigh you down.
Why not visit our list of the Top 5 Sleeping Bags of 2025 to see how the Therm-a-Rest Hyperion 20 compares?
Water & Outdoors reviews are written by our staff writers, who combined have over fifty years of experience on the water and outdoors. We may earn commissions if you choose to buy through a link you’ve clicked on our website, however this does not influence our reviews. For more information, please see our Editorial Policies.