Therm-a-Rest Questar 0 Sleeping Bag Review

May 9, 2019
Therm-a-Rest Questar 0 Sleeping Bag
Therm-a-Rest Questar 0 Sleeping Bag Thermarest_Questar-01 Thermarest_Questar-02 Thermarest_Questar-03 Thermarest_Questar-04 Thermarest_Questar-05 Thermarest_Questar-06 Thermarest_Questar-07 Thermarest_Questar-08 Thermarest_Questar-09
Water Resistance

The Good

  • Soft and Comfortable
  • Hydrophobic down
  • Many warmth-enhancing features
  • Light weight
  • affordable

The Bad

  • Not as compressible as bags with higher quality do
  • Compression sack not included
Sleeping in the Questar is a dreamy experience. It feels warm and light, and pads around the body in all the right places. Every tester that used this bag remarked on its impressive comfort. It even has a stash pocket on the outside, providing extra convenience. At 2 lbs 13.8 oz, it is the third lightest down winter bag that we tested, so it can be comfortably carried on human-powered adventures. Nikwax hydrophobic down increases its performance when up against condensation gathering inside a tent. Though this bag did not earn the same score as the award-winning Feathered Friends Snowbunting EX, the Questar is half the price, making it an excellent deal for such a high-quality product.

New in 2018, the Therm-a-Rest Questar 0 is a luxuriously comfortable and well-featured winter sleeping bag. What really stands out about this product is its value. It earned our second highest score, after the Feathered Friends Snowbunting EX, but it costs half as much. For someone in need of a bag for winter camping but without a limitless budget, the Questar is an excellent choice.


This sleeping bag has been taken on an overnight ski tour on Mount Lassen, spent four early spring nights car camping in Grand Staircase-Escalante National Monument, and Thanksgiving week car camping in Death Valley National Park. Each testing scenario involved cold nights and required a warm bag to keep the camper comfortable. We had different testers of varying ages and levels of outdoor savvy use the Questar and they all came back with roughly the same impression: this bag is incredibly warm, cozy, and comfortable.

It is filled with 1 lb, 13 oz of 650-fill Nikwax Hydrophobic down. This down is lofty and warm, though not quite as lightweight or as compressible as higher fill-power down. Many of the features on the bag contribute to its feeling of warmth: a thick draft collar that covers the entire circumference of the bag, a draft tube that runs the length of the zipper, and a cinchable insulated hood. Additionally, Therm-a-Rest has included its proprietary Thermacapture technology on the seams. This is a reflective coating which radiates body heat back at the occupant. We can feel that there is a thicker and stiffer tape on along the inside of the interior seams, which is the Termacapture. In theory, this reduces the chance that the seams will feel like cold spots. In practice, it was difficult for us to differentiate what features were making us feel warm when in the Questar, but we did feel plenty warm.

A note about the temperature rating of this bag: the Questar is EN rated with a 0ºF Limit rating and a 14ºF comfort rating. This means that even though the bag is marketed as a 0ºF bag, it probably won’t feel warm and cozy at that temperature. It is adequately comfortable at the 14ºF range. Be aware that if the temperature really is going to be around 0 degrees when you are camping, depending on how warm or cold you sleep you may want to wear a puffy jacket inside the bag or use a sleeping bag liner to increase the warmth. You will survive a 0ºF night in the Questar, but it may not be as pleasant as you imagine.


Therm-a-Rest lists the weight of the Questar as 3 pounds, but on our scale,  it was under that at 2 lbs 13.8 ounces. In our test, this ranks third for weight, behind the Sierra Designs Nitro and the Feathered Friends Snowbunting. For a winter bag, we think this is a completely reasonable weight and are happy to carry it if it means a night of warmth, comfort, and safety

Water Resistance

The Questar is treated with a DWR, or durable water repellent finish, which encourages water droplets to bead-up on the surface of the material rather than soak in and drench the insulation. This coating works well for a while but eventually wears off. So, the Questar has another feature to keep it performing well in damp conditions: Nikwax hydrophobic down. The down feathers have also been treated with a DWR-like coating which resists moisture. If the feathers do come in contact with water, it takes more moisture and more time before it loses its loft. This treated down is not a substitute for synthetic insulation in extremely wet conditions, and the loft will still collapse if soaked. The hydrophobic down does increase the bag’s resiliency in average winter camping conditions, such as when condensation and light snow coming in contact with the sleeping bag.


The 650-fill down inside the Questar, though plenty to keep a sleeper warm, does not compress as well as the 900+ fill in the Feathered Friends Snowbunting. The Snowbunting is a very large bag with lots of extra space in it. The Questar is a much smaller and more compact bag, even though both are size Regular. However, the Snowbunting stuffs down into a smaller package than the Questar, which we attribute to the down quality. However, the Questar packs far smaller than the three synthetic bags included in this test, which makes it a much more desirable item for any type of human-powered overnight.

None of the down bags in this winter sleeping bag test came with a compression sack, and all of them could pack even smaller in a sack that has compression straps. If you plan to backpack or ski tour with the Questar, we recommend purchasing an after-market compression sack, which will make the packed size much more manageable.


On a winter bag, features are more important than on a lightweight summer bag, or even a three-season backpacking bag. It is nice to have a few more creature comforts to keep you warm and dry when winter camping. This is a category where the Questar shines. Beyond the obvious big features such as low weight, adequate warmth, and hydrophobic down, the Questar has several other notable features that make it cozy. First, there is a zippered pocket on the outside front of the bag. This is a perfect place to keep a headlamp, chapstick, a phone that you want to prevent from getting too cold and killing the battery, or a contact case that you want to keep warm so the fluid inside doesn’t freeze.

The hood has an easy to use cinch, and the color snaps shut on top of the zipper to prevent it from working its way open throughout the night. For the whole circumference of the bag is a thick and fluffy draft collar that seals warm air in around your body, preventing it from escaping out past your neck. Once sealed inside the hood with the snap closed and the draft collar in place, the sleeper is surrounded by insulation and there is very little room for body heat to escape or cold air to get in.

The ¾-length side zipper also has a draft tube that extends for its entire length, ensuing that the zipper does not become a cold spot. The material next to the zipper is reinforced with thick tape on both sides, which prevents snagging, making the zipper easy to use, even in the dark.

And finally, the Questar has several special loops and connection points. It comes with Therm-a-Rest’s Synergy Link connectors, which are removable stretchy bands that attach the bag to a sleeping pad to prevent the sleeper from rolling off of the pad at night. There are also additional loops that can be used to attach other Therm-a-Rest quilts or blankets in case more insulation is needed.


Where several other bags in this test feature a 15-denier shell material, the Questar uses a slightly sturdier material of 20-denier coated with a durable water repellent finish. This is not as tear resistant as the 70-denier polyester used on the Backcountry Montana, but unlike the Montana, the Questar remains remarkably lightweight while providing adequate durability. We have found that the zippers and cinches all function well and are pleased with its performance.

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