Thermarest Corus 20 Down Quilt

-6°C Comfort Limit (EN13537:2012), 525g of 650 Fill Power Down (US Method)
Weighs 772g (Regular bag)
Code: SS20537V
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Lightweight, comfortable and super warm. The Corus is a top-rated camp quilt that is extremely packable for your camping and backpacking adventures. It provides the perfect blend of functionality and warmth.

Thermarest says:

The same versatility you love with even more down loft to keep the colder backcountry conditions at bay. Its perfect balance of functionality and warmth make it ideal for three-season backcountry adventures or for layering in colder conditions. Made with high loft, packable Nikwax Hydrophobic Down and Box Baffled construction for retaining heat and excellent temperature regulation, the Corus offers a surprisingly liberating feeling of unrestricted movement throughout the night. The footbox can slip over your pad to eliminate drafts or over your feet for extra warmth.

The Therm-a-Rest's 2020 Corus 20 Down Quilt, is ideal for those seeking ultralight performance and amazing comfort without a weight penalty. It features a huge amount of 650 fill of responsibly sourced Nikwax Hydrophobic down which vastly improves its performance in damp conditions and takes the Comfort Limit down to an impressive -6°C. The impressive box wall construction for the baffles is something you only get on top quality down products as this technical aspect allows down to loft much more effectively while also reducing heat loss through cold spots along stitch lines. 

The spacious footbox fits round the bottom end of your sleeping mat keeping your feet warm and the quilt in place. It also includes poppered snap loops so it can easily be connected to a Thermarest mattress, quilt blanket or sheet allowing you to build a your own sleep system. There is a small pocket at the head end for those essentials you might need to find in a hurry such as a head torch. As you would expect it the pack size is tiny. If you're after a little bit of light-weight luxury on your next adventure then this quilt would be ideal.

- Reviewed by Ultralight Outdoor Gear

Help and advice: Choosing a sleeping bag advice
  EN 13537 rating for sleeping bags explained
  Sleeping bag shape and sizes advice
  Sleeping Bag features Page 1
  Sleepin bag features page 2
  All about down filling in sleeping bags
  • 650 Fill Nikwax® Hydrophobic Down™: Absorbs 90% less water and dries 3 times faster without using dangerous PFCs.
  • Compact: Designed to easily fit into your pack.
  • Box Baffled Construction: Uses mesh walls to maximize down loft and minimize cold spots.
  • SynergyLink™ Connectors: Integrate the quilt with a pad for optimal efficiency and comfort; removable for versatility.
  • Thoughtful Footbox: Precisely shaped footbox can slip over your pad to eliminate drafts or over your feet for extra warmth.
  • Draft Protection: Full-perimeter side baffles and snap neck closure keep out unwanted drafts.
  • Build a System: Pair with another Therm-a-Rest quilt, sleeping bag, blanket or sheet to build a layered system.
  • Responsible Down Standard Certified: Certification that ensures that the waterfowl in the down supply chain are treated humanely.
  • Stuff sack and storage sack included

Temperature Rating

  • EN13537:2012 Comfort: 0°C / 32°F
  • EN13537:2012 Comfort Limit: -6°C / 20°F


  • Weight: 772g (excludes bags)
  • Fits: 183cm / 6ft
  • Shoulder girth: 126cm / 49.5in
  • Hip girth: 121cm / 47.5in
  • Footbox girth: 64cm / 25in
  • Fill weight: 525g
  • Packed dimensions: 19 x 29cm / 7.5 x 11.5in


  • Weight: 828g (excludes bags)
  • Fits: 198cm / 6ft 6in
  • Shoulder girth: 135cm / 53in
  • Hip girth: 131cm / 51.5in
  • Footbox girth: 76cm / 30in
  • Fill weight: 560g
  • Packed dimensions: 19 x 29cm / 7.5 x 11.5in


  • Shell: 20D Polyester RipStop w/ DWR
  • Lining: 20D Polyester Taffeta
  • Insulation: 650 Fill Nikwax Hydrophobic Down RDS
Showing our 1 review for Thermarest Corus 20 Down Quilt. Write a review ›
Review Summary - 1 out of 5 based on 1 rating.
April 4, 2021 | Anne

I have used quilts for years as I prefer the flexibility and versatility of them. I have on rated for 0 degrees and it seemed like a good idea to get this one rated for -6 for Scottish spring and autumn time adventures. My current Enlightened Equipment quilt works because it has clips so you can close it at 4 points around your body and whilst it doesn't close completely, it does a good job at retaining heat. The Corus only wishes it could do any of that and lets just say I was only out for 1 night because this product failed on all fronts. 1) various cold spots throughout, the toe-box 'which can be slotted around your mattress to keep your feet nice and warm' was an icebox. My feet were icy cold all night (I had socks on.. took them off to see if direct body heat would help but nope, it stayed cold. 2) the shoulder baffles which are supposed to keep the draft out... don't work either. Unless you lie completely flat and don't move an inch, sure it may work. But as soon as you turn or even more you foot or leg, the quilt comes up and freezing air is let in. 3) so called straps to help keep the bag secure. Sure they do that but they don't help keep the heat in at all... they are too flimsy. Overall - I think Thermarest are trying to get into the quilt game but the design is poor and I wouldn't take this quilt on a summer trip. The quilt is not wide enough, meaning you can't wrap it around your mat and really form a little cocoon, nor can you cinch it in around your body (almost acting like a sleeping bag) to keep heat in that way - the cold spots are a mystery to me seeing as its a brand new quilt and the straps don't do anything really. Poor design and not nearly 20F rating. Very disappointed.

Ultralight Outdoor Gear Limited