For this test we defined winter sleeping bags as those with a temperature range of 0ºF to 14ºF. These are best used for overnight ski tours, backcountry mountaineering trips, and car camping in the months of November through February.
The Best Winter Sleeping Bags (0-14F)
Camping in winter is a far different proposition than summer camping or backpacking. Some conditions or environments you may encounter are snow, ice, freezing rain, glaciers, or bitterly cold and dry desert. The overnight gear required to keep you warm and dry in cold and wet weather needs to meet different parameters than a fair-weather summer bag. In winter, having a sleeping bag that performs well might even keep you alive in inhospitable temperatures.
For the sake of this test, we defined winter sleeping bags as those for temperatures between 0-14 degrees Fahrenheit. For high altitude expeditions, something warmer is most likely required, while winters in other low-lying regions might be mild enough that a three-season model would suffice.
We called in seven different models that span a range of prices from the most respected brands, and we chose to split the difference between synthetic and down insulation. Synthetic insulation has the benefit of maintaining its loft when wet, so it is appealing for winter camping, which tends to be stormy and drizzly.
Nine testers of differing ages, genders, and ability levels tried these seven products in a range of conditions on a variety of winter camping trips. We took the bags on overnight ski tours in the high Sierra, on a two-week expedition to the Pika Glacier in Alaska, and on a week-long winter trip to Death Valley National Park. We found some models were ideally suited for skiing and mountaineering while others are more comfortable for car camping in the months between November and February.
https://gearinstitute.com/wp-content/uploads/WinterSleepingBags-02-800x300.jpgby: McKenzie Long
Winter camping often involves sleeping on top of snow and waiting out bad weather. We did both things at the same time for many nights during this test, both in Alaska and in the Sierra. Each bag was slept in, sweated in, and lounged in. Each one got damp from weather and condensation. Each was compressed, packed, and re-lofted many times.
For three-season and summer sleeping bags, ventilation is an important scoring metric because those bags need to be warm when nights get cold, but also need to transition well to use in higher temperatures. For winter bags, weather and water resistance are far more important than the ability to ventilate, so we altered our evaluation criteria in this test. Almost every single product was slept in during a snowstorm.
We have defined winter sleeping bags as those for 0ºF to 14ºF temperatures, which is common for low altitude camping during the winter months.
All seven of the products in this test are marketed as 0ºF bags. It is difficult to compare these items based only on this spec because not all companies rate their bags in the same way. EN (European Norm) tests are an industry-accepted standard that makes temperature ratings easy to compare across brands, but not every brand submits their products to this testing. EN ratings include two primary temperature ranges, a Comfort rating, which is the temperature at which the bag will feel comfortable to a cold sleeper (a typical female) and a Limit rating, which is the temperature at which the bag will feel comfortable to a warm sleeper (a typical male.)
Three bags in our selection do have EN ratings, which are all very similar: Therm-a-Rest Questar (0ºF Limit/14ºF Comfort), The North Face Guide (3ºF Limit / 17ºF Comfort), and the Sierra Designs Nitro (2ºF Limit/15ºF Comfort).
In field testing, we found that the Feathered Friends Snowbunting was the warmest bag. It is the loftiest by far (more than double the size of the other bags when uncompressed in its large storage sack) and has an excellent hood and draft collar combination to keep body heat inside.
Since down insulation has a higher warmth-to-weight ratio, the weight discrepancy between the down models and the synthetic versions is quite large in this test. The heaviest bag weighs over a pound and a half more than the lightest bag. All of the synthetic bags weigh over three pounds due to the amount of insulation used to make the bags warm enough for winter camping.
The lightest bag in this test, weighing 2 lbs, 8.6 oz, is the Sierra Designs Nitro. The Nitro compresses well too, making it a great choice for packing into a backpack and carrying long distances. It is, however, a little less warm than its competitors. Both the Feathered Friends Snowbunting and the Therm-a-Rest Questar are close behind the Nitro, weighing 2 lbs, 13.2 oz, and 2 lbs, 13.8 oz respectively.
The heaviest bag is the Backcountry Montana at 4 pounds 3. 8 ounces. If possible, we would avoid bringing this large and heavy bag on human-powered missions and reserve it for adventures that don’t involve carrying it very far.
Insulation works by trapping pockets of body-heated air in between small pieces of material. Down creates these pockets in the space between the filaments of the feathers. Synthetic insulation mimics this by creating small spaces in between some type of thin manmade polymer. If these small air pockets do not exist, heat cannot remain trapped there and is lost to the outside air. This is why down insulation does not work when it gets wet: the feathers clump together and all spaces for warm air are lost. And this is why synthetic insulation can function in wet conditions: the material does not collapse, so even though it may be soaking wet, there are still spaces to trap warm air and prevent a person from freezing.
Therefore, water resistance is one category where the synthetic bags score higher than down models. The North Face Guide, Backcountry Montana, and Marmot Trestles Elite can all hold up well if caught in a storm.
Of the four down sleeping bags in this test, three are filled with hydrophobic treated down. This down is coated so the feathers have more time and can be in contact with more moisture before it begins to clump up and lose loft. These hydrophobic treatments are similar to the DWR (durable water repellent) coatings that are used on the shell materials. These treatments cause small amounts of water to bead up and roll off the material rather than soak in. On the exterior of the bag, these coatings wear off over time and do not provide lasting water resistance. The three bags that include both hydrophobic down and DWR treatments, Therm-a-Rest Questar, Big Agnes Yock, and the Sierra Designs Nitro, all have a little extra resistance to weather than if they did not have these treatments.
The final product in our test, the Feathered Friends Snowbunting, employs a different strategy. It features natural untreated down, which some companies argue has superior water resistance than treated down, and a waterproof/breathable shell material, Pertex EX. This makes it unlikely that water will ever reach the down, at least through the top shell material (the interior lining is not waterproof). Even when waiting out a storm in Alaska, the bag never got soaked and we felt very confident in it.
Just as with the weight metric, there is a large discrepancy between the synthetic and the down models in compressibility. Each of the synthetic bags is enormous; none pack smaller than a watermelon. Luckily, each of the synthetic sleeping bags comes with a compression sack so the user can cinch them as tight and as small as possible.
The most compressible bag is the Feathered Friends Snowbunting with 900+ fill down. This is the largest bag in terms of uncompressed size, and it packs down into one of the smallest packages. The Sierra Designs Nitro packs down quite small for a 0ºF bag, but it is thinner and smaller to begin with.
A basic winter sleeping bag should have a few staple features, and we found variations of these features on all seven models in this test: an insulated hood with a cinch for tightening around the face, a draft collar for sealing warm air in around the neck and shoulders, and a draft tube running along the interior of the zipper to prevent cold air from seeping in between the zipper’s teeth. Four out of seven models in our test (Questar, Guide, Trestles Elite, Montana) also include a stash pocket, which is extra helpful when winter camping because it allows you to keep important personal items warm and close to you, such as a headlamp, chapstick, phone, or contact case.
To assess durability, we looked at a few different things: the denier (or density of fibers used) in the shell material, the zippers and the anti-snag features, and the overall feel and performance of the bag during testing. We did not have any rips or obvious failures during our testing period, which is a testament to the high quality of all products tested.
Our favorite zipper was the beefy anti-snag slider on the Feathered Friends Snowbunting. The bag with the burliest shell material was the Backcountry Montana, with an impressive 70-denier polyester. We felt that the Montana was the most durable and least fragile of all the bags we tested.
In terms of durability, synthetic bags have better short-term durability while down bags typically are longer lasting. Synthetic insulation is composed of long sheets of material rather than small individual pieces, like down. So synthetic bags are less vulnerable to rips and tears, because if a hole is torn in the shell material, the insulation will not leak out. Down insulation, on the other hand, can withstand more years of compressions and expansions than man-made insulation, so if well-cared for, a down bag can last longer overall.
We had the luxury of testing these winter sleeping bags over the course of many months. This allowed us the time to really put these products to hard use, expose them to different types of weather, to plan some big trips, and to get numerous testers to provide feedback.
Our first big test was an expedition to the Pika Glacier in the Alaska Range, an area commonly referred to as Little Switzerland. Several testers brought a test model with them for two weeks spent camping on the glacier. The team was flown in by air taxi and they established a basecamp not far from the runway, so the bags didn’t need to be carried very far. After one day of climbing, these testers had the fortunate test conditions (though unfortunate climbing conditions) of waiting out a 10-day storm. This allowed for ample observation of warmth, water resistance, comfort, and durability.
After that several bags were used on overnight ski tours, where weight and compressibility are a larger concern, but the warmth and water resistance are still primary factors in performance.
Finally, all of the bags were taken on a weeklong Thanksgiving camping trip in Death Valley National Park, where nighttime temperatures can get quite cold.
On top of this field testing, each bag was weighed on our own scale, detailed research was done about each product, and many notes were taken. All of this information has been compiled to bring you this detailed comparison review.
What is a Winter Sleeping Bag?
We define a winter sleeping bag as one for temperatures between 0ºF to 14ºF. For colder temperatures or high altitudes, you will need an expedition bag that is even warmer. Since winter bags will most often be used around snow, water resistance is an important feature, both in the shell material and in the insulation. Here are the most important weather resistance features to keep in mind, and what the trade-offs for each one.
Waterproof Shell vs. DWR
A winter bag will either have a fully waterproof/breathable material for the shell or a DWR (durable water repellent) coating applied to non-waterproof nylon or polyester. DWRs work well at first but wear off over time, so a waterproof shell material will be more reliable, more water resistant, and longer lasting. This type of material will increase the price of the product overall.
Insulation works by retaining warm air in spaces between small bits of material. In down, the filaments of fluffy feathers trap heat and hold it in place. In synthetic insulation, small pockets exist in between manmade fibers.
Synthetic insulation maintains its loft even when wet because the material does not clump together or collapse on itself when it gets damp. This is its primary benefit: having synthetic insulation can be an extra layer of safety when out in cold and wet conditions. The downside is that this type of insulation is heavier and bulkier for the same level of warmth.
Down has a higher weight-to-warmth ratio than synthetic insulation, so a down bag will be lighter weight than a synthetic bag of the same warmth. This is obvious in our test results, where all the down models weighed less than the synthetic alternatives. This makes down a more attractive choice for carrying in a backpack for long distances. Unfortunately, it costs more than synthetic insulation and it is vulnerable to getting wet. If a down bag does get drenched, the insulation will clump together and become useless.
Natural Down vs. Hydrophobic Down
These days most manufacturers are treating down feathers with a DWR coating to give them more resilience to moisture. This does seem to work when the insulation comes in contact with a small amount of precipitation or condensation for a small amount of time, but it does not help if the bag gets completely soaked. Some manufacturers will argue that high quality down has more natural water resistance than treated down.
Caring for your down sleeping bag
Make sure to store your bag in its large storage sack and not compressed. This will give the insulation a longer life. Most modern sleeping bags also come with hanging loops if you prefer to store hanging in a closet. Also, keep in mind that washing your down sleeping bag every once in a while, will improve its loft. Over time oils can make the down clump together and seem more packed out. A good washing will restore it back to normal.
The 900+ fill down keeps the Feathered Friends Snowbunting EX lightweight and compressible so that it is perfect to bring on human-powered winter adventures while the waterproof/breathable Pertex Shield EX shell withstands occasional moisture and condensation dripping onto the bag. The Snowbunting is extra roomy for a size regular, which allows the sleeper to stash boot liners, gloves, and socks into the bag with them so that they can warm up and dry out overnight rather than freeze. This is key for winter mountaineering or overnight ski touring. The drawback is that smaller people might find that this bag to be too drafty. Our overall impression was that this was the most cleverly designed and well-featured bag for those who like to be in the mountains in winter.
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.
For ski tourers and mountaineers who want a lightweight winter bag for human-powered adventures, the Sierra Designs Nitro serves that need. We recommend pairing it with a lightweight, high R-value sleeping pad such as the Therm-a-Rest XTherm to get the most out of it. The Nitro is not the warmest or the most waterproof bag in our review, but it performed well for our testers even in snowy and stormy conditions. The Feathered Friends Snowbunting is more tailored to the serious mountaineer, but the Nitro wins in the weight category, contains hydrophobic treated down, and is more affordable, making it an attractive option for the weight-conscious and cost-conscious customer.
The North Face Guide is our favorite synthetic winter sleeping bag. The materials feel soft and cozy against the skin, there is a convenient stash pocket, and it is lighter and warmer than the other two synthetic models in this test. Since the Heatseeker Guide insulation will maintain its loft even when wet, the Guide is our choice for wet climates and stormy weather.
Though not as flashy or high performance than some of the other bags in this test, the Big Agnes Yock proved to be dependable and reliable in a variety of conditions. It also seems durable and well made so it is likely to last a while. Two testers slept side-by-side in the Yock and the Feathered Friends Snowbunting for two weeks on a glacier in Alaska, and both were equally warm. Yet the Yock costs half the price of the Snowbunting. If you are looking for a quality sleeping bag to keep you warm in winter but don’t want to dig into your savings, the Yock is an excellent choice.