Thermarest Questar 20 Down Sleeping Bag

-6°C Comfort Limit (EN13537:2012) 540g of 650 Fill Power Nikwax Hydrophobic Down (US Method)
Weighs 1002g (Regular bag)
Code: SS20531V
  • £219.99
  • (FREE Delivery on orders over £15)
  • RRP £239.99
+ In Stock Now | Usually dispatched within 24 hours

Dialed in for backpacking adventures, the fully-featured Questar 20 Sleeping Bag delivers three-season comfort with 650 fill Nikwax Hydrophobic Down.

Thermarest says:

This is the award-winning, feature-packed down bag you've always wanted. We've loaded this bag with the comfort features that Therm-a-Rest bags are known for. Our SynergyLink™ Connectors integrate the bag with your sleeping pad while allowing our Zoned Insulation to keep fill where you need it most. The fit of the bag has been perfected in our onsite cold chamber to create our W.A.R.M. fit that allows room for multiple sleep positions without compromising thermal efficiency. Stuffed with water-resistant 650 fill Nikwax Hydrophobic Down certified by the Responsible Down Standard, the four-season Questar is ready for your next backcountry adventure. The Questar is offered in three sizes, and designed to fit both men and women. Compression sack and storage sack included.

Therm-a-Rest's Questar range has been expanded and updated with new fabrics, a new fit and more choices depending on what you need from your bag. The range still uses 650 fill power down that has been treated with Nikwax to make it hydrophobic meaning that it absorbs a lot less water and dries faster when needed. The value is still there with the Questar as you are getting a really good quality bag at a very reasonable price. This version has a Comfort Limit of -6°C so it is versatile enough to stretch through three season conditions with ease.

The bag has a more generous fit than many other mummy shaped designs so if you move around a lot during the night or simply want a bit more space, this is a decent option. It has box baffle construction which minimises cold spots and increases the amount of loft the down can get and therefore the warmth it can trap. There is also an extra foot pocket inside to provide a bit more comfort and warmth, particularly for anyone with cold toes. 

It has all the usual features you'd expect from a quality sleeping bag including a draft collar, full-length zipper draft tube, snag-free zipper, cinchable hood and external zip pocket. In addition to these there are also sleeping mat connectors on the back of the bag and loops on the front so you can add a quilt, both building on the versatility of the Thermarest sleep system concept.

- Reviewed by Ultralight Outdoor Gear

Read reviews here:

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. 
  • W.A.R.M. Fit: With Additional Room for Multiple positions (W.A.R.M.) fit means this bag allows for various natural sleep positions while maintaining thermal efficiency.
  • SynergyLink™ Connectors: Integrate the bag with a pad for optimal comfort and thermal efficiency; removable for versatility.
  • Zoned Insulation: Maximizes warmth and saves weight by intentionally placing down where you need it most.
  • Box Baffled Construction: Uses mesh walls to maximize loft and minimize cold spots.
  • Toe-asis™ Foot Warmer Pocket: Baffled pocket of insulation rapidly warms cold feet.
  • Quilt and Blanket Loops: Customize your sleep system by layering our quilts or tech blankets for increased warmth.
  • Responsible Down Standard Certified: Certification that ensures that the waterfowl in the down supply chain are treated humanely.
  • Additional features: Heat-trapping draft collar, full-length zipper draft tube, snag-free zipper, cinchable hood and external zip pocket.
  • Compression sack and storage sack included

Temperature Rating

  • EN13537:2012 Comfort: 0°C / 32°F
  • EN13537:2012 Comfort Limit: -6°C / 20°F
  • EN13537:2012: -23°C / -9°F


  • Weight: 896g (excludes bags)
  • Fits: 168cm / 5ft 6in
  • Shoulder girth: 147cm / 58in
  • Hip girth: 147cm / 58in
  • Footbox girth: 112cm / 44in
  • Fill weight: 470g
  • Packed dimensions: 17 x 22cm / 6.5 x 8.5in


  • Weight: 1002g (excludes bags)
  • Fits: 183cm / 6ft
  • Shoulder girth: 160cm / 63in
  • Hip girth: 155cm / 61in
  • Footbox girth: 117cm / 46in
  • Fill weight: 540g
  • Packed dimensions: 17 x 22cm / 6.5 x 8.5in


  • Weight: 1096g (excludes bags)
  • Fits: 198cm / 6ft 6in
  • Shoulder girth: 168cm / 66in
  • Hip girth: 163cm / 64in
  • Footbox girth: 130cm / 51in
  • Fill weight: 610g
  • Packed dimensions: 17 x 22cm / 6.5 x 8.5in


  • Shell: 20D Polyester RipStop w/ DWR
  • Lining: 20D Polyester Taffeta
  • Insulation: 650 Fill Nikwax Hydrophobic Down RDS
Showing our 2 Thermarest Questar 20 Down Sleeping Bag reviews with an average rating of Excellent. Would you like to write a review?
Review Summary - 5 out of 5 based on 2 ratings.
October 25, 2021 | aria max
Superb comfortable

Used this bag for 3 weeks on the Baltoro all the way up to Concordia, slept as snug as a bug in a rug! Superb, comfortable performance sleeping bag.

Ultralight Outdoor Gear Limited
November 15, 2020 | Philip
I hated sleeping bags, until.....

So I've always hated sleeping bags, except for the lovely rectangular cotton ones we had as kids, that weigh 3kg! This has totally changed that. I'm 6ft tall, slim build, a side sleeper and I sleep cold when camping. The room in this bag is so lovely and so comfortable, combined with the 'toe-asis' , I can finally be comfortable. The regular size is perfect while leaving plenty of room for a pillow (Thermarest compressible - small). The zipper is incredible and hardly ever snags. The draft collars keep me so cosy and the whole bag is just so well made. Side sleeper? Don't like mummy bags? You do now....

Ultralight Outdoor Gear Limited