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Therm-a-Rest Questar 20 Down Sleeping Bag (-6C)

Therm-a-Rest Questar 20 Down Sleeping Bag (-6C)
$429.95 - $469.95
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This is the field-proven, feature-packed down bag you've always wanted. Thermarest has loaded this bag with the comfort features that their bags are known for.

Thermarest 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 the Thermarest onsite cold chamber to create the Thermarest 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 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.

Weight (Reg) - 990g / 2.19lbs
Fill: 650 Fill Power Nikwax Hydrophobic RDS Duck Down
Fill Weight: 540g / 1.19lbs
Bag Shape: W.A.R.M. fit

  • 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


Recommended Use



Three Season (-1C to -15C)

Temperature Rating


Comfort Limit


Lower Limit




Insulation Type

650+ Fill Power

Nikwax Hydrophobic Duck Down


Small - 0.84 kg / 1.85lbs

Regular - 0.99 kg / 2.18lbs


Long – 1.12 kg / 2.46lbs

Fill Weight

Small: 0.47 kg/ 1.03 lbs

Regular: 0.54 kg/ 1.19 lbs

Long: 0.61 kg/ 1.34 lbs



Fits to User Height

Small - 168cm /66”

Regular - 183cm /72”

Long - 198cm / 78"




Small - 185 cm / 73"

Regular - 203 cm / 80"

Long - 216 cm / 85"



Small - 147 cm / 58"

Regular - 160 cm / 63"

Long - 168 cm / 66"




Small - 147 cm / 58"

Regular - 155 cm / 61"

Long - 163 cm / 64"




Small - 112 cm / 44"

Regular - 117 cm / 46"

Long - 130 cm / 51"



Stuff Sack Size

19 x 23cm / 7.5 x 9"

Packed Volume

14.8 liters



20D Polyester w/ DWR


20D Polyester Taffeta

Ultralight Fit 

As the name suggests, this fit is all about trimming weight and compact packing. Bags and quilts with this fit are specialized pieces of gear. They are narrower throughout the shoulders, hips and footbox. Less internal space means less energy required to heat it, as well as less energy expended to carry it. It also means less room to move around and get comfy at night.


If you are all about ultralight packs for fast backcountry travel, and willing to sacrifice some comfort for it, Ultralight Fit is optimized for you. If you are a side sleeper you may feel confined in one of these bags..


Performance Fit 

Like Ultralight Fit, the bags and quilts with Performance Fit are only in our Fast & Light category. The point is to provide ultralight options to sleeper profiles that require more space for better rest. Examples would be side sleepers or cold sleepers that may be donning extra layers—like a puffy jacket—for overnight warmth. The extra internal space may add grams, but that is justified price to pay if it means you will be better rested.


These bags and quilts are still compact, lightweight and altogether designed for the backcountry. Still, with a touch more room for comfort a Performance Fit piece will be better suited for weekends in the crag parking lot or general car camping than Ultralight Fit bags and quilts. If you are a comfort-conscious thru-hiker, or a backcountry traveler that knows your trip schedule includes car camping as well, performance fit is an excellent option.


W.A.R.M. Fit 

With Additional Room for Multiple Positions. It may be an imperfect acronym, but we really want you to know that the extra room in these bags and quilts DOES NOT result in cold spots (we’ll explain why in a moment). Continuing up the spectrum from Performance Fit, W.A.R.M. bags and quilts comprise the Trek & Travel line.


The concept is to offer backcountry ready sleeping bags and quilts that allow a wide range of natural sleep positions. The point of a sleeping bag or quilt (really the point of our whole company) is to achieve quality nighttime rest in the outdoors. If you are a side sleeper, an active dreamer, or a position pluralist a narrow sleeping bag can be really frustrating (or downright claustrophobic) and rob you of good, solid sleep.


W.A.R.M. Fit bags are great for backcountry travelers that move around in their sleep, or are otherwise uncomfortably confined by narrow bags, and willing to add some weight for better sleep. What’s more, these bags and quilts are well suited for frontcountry adventures. When weight and packed size are of lesser concern, why not prioritize comfort? If your adventure calendar has you backpacking deep into the wilderness but also spending quality time car camping with friends, W.A.R.M. Fit is a strong choice for you.

Bag Storage

 The less time your sleeping bag is compressed, the longer it will serve you by maintaining the loft necessary to keep you warm. Store your sleeping bag loose, in a cool, dry place. If you must store it in a bag, use the extended storage sack it came in, or something even larger. Never use a waterproof bag for long-term storage.



Hand wash or machine wash in a large capacity, front loading washing machine, using 3 oz. of Nikwax Down Wash Direct. Select cold water and a gentle/delicate cycle with two rinses. We recommend an additional spin cycle as well to extract as much water as possible before drying.

DO NOT dry clean. DO NOT bleach. DO NOT iron.



Hang dry your bag whenever possible. This can be a long process (24-48 hours or more), but this is by far the best way to get the longest life from your down.

Use a well-ventilated, low-humidity environment. Hand-tease or shake out your bag gently to break-up down clumps, and flip it often to help speed the process.

 If you need to dry your bag faster, tumble dry in a large dryer on low heat. As your bag gets drier, it will begin to loft and can actually fill the dryer chamber, preventing it from tumbling.

This can cause hot spots and even melt the bag’s shell, so check it often for overheating and visually inspect frequently to make sure it’s tumbling.

When you check it, feel for clumps of wet down and either shake the bag gently or hand-tease the clumps apart to redistribute down.

Throwing in 3-5 tennis balls can help agitate the bag, breaking up those wet down clusters to speed dry times.


Nikwax® Hydrophobic Down Treatment and Re-Treatment

Use Nikwax® Down Proof™ to restore your down’s hydrophobic properties. Specially formulated to renew the Nikwax Hydrophobic Down treatment, it can also be used to provide improved water-resistance to any down bag. Follow directions on the bottle.


Thermarest Questar Sleeping Bags

Part Numbers

Option UPC MPN Store SKU
Small 040818131558 13155 SLE513900720
Regular 040818131565 13156 SLE517484460
Long 040818131572 13157 SLE524963150