Choosing the best winter sleeping bags can be overwhelming, but we have broken it down to a simple list of the Top 6 Bags of 2021.
High-value insulation, compressibility, low weight, and ample interior space are the most critical features of a sleeping bag for winter camping and backpacking, so you have enough room to stash gear and water in your sleeping bag so it doesn’t freeze overnight. Cost is also a consideration, though if properly cared for and stored, a proper winter sleeping bag can last fifteen years or longer. We recommend down-insulated winter sleeping bags for winter camping and other adventure hobbies such as backcountry skiing and ski mountaineering because it packs smaller and is lighter weight.
A 0-degree sleeping bag is the most bang for your buck, as you can boost its warmth with a low-cost liner if you need to sleep in colder temps. When temperatures drop below zero, most people tend to avoid winter camping and backpacking, but they are missing out! As long as you’re properly prepared, weather shouldn’t be too scary!
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Top 6 Winter Sleeping Bags
Here are our Top 6 Picks for cold-weather camping and backpacking down winter sleeping bags. See our evaluation criteria and buying advice below for more information and answers to frequent questions.
Marmot Lithium 0 Sleeping Bag
The Marmot Lithium is a feature-rich mummy-style sleeping bag insulated with 800 fill power water-resistant goose down. It has a full-length two-way zipper with a draft tube and snag guard, so you can vent the bottom by your feet or anywhere you’re too warm. The Lithium has an adjustable, double-sided draft collar that runs over your chest and neck and behind your back to seal in your warmth. A second 1/4 length zipper on the other side provides additional ventilation and increases the bag’s range of use. Unisex.
Kelty Cosmic Ultra 0 Sleeping Bag
The Kelty Cosmic Ultra is the ultimate in a lightweight mummy. They’ve taken their top-selling Cosmic Bag and added an 800 fill DriDown version, with all the perks too. The new trapezoidal baffle construction is ideal for retaining heat-and it’s just one of the reasons Cosmic is still a favorite three-season superstar. Users also love the natural fit foot box for happier feet and a PFC-free water-repellent coating for a healthier environment.
Nemo Sonic 0 Sleeping Bag
The NEMO Sonic 0 is a mummy-style sleeping bag insulated with 800 fill power water-resistant down. It has a highly adjustable draft collar that encircles your neck and shoulders as well as a zipper draft tube to seal in warmth. The Sonic 0 has innovative Thermo-Gills (see picture) that let you release up to 20 degrees of warmth so you can regulate your temperature without cracking open the zipper and introducing cold drafts. Unisex.
Sierra Designs Nitro UL 0 Sleeping Bag
The Sierra Designs Nitro UL 0 is a low-cost 1/2 zip mummy-style sleeping bag insulated with 800 fill power water-resistant down. Weighing just 2 lbs 8 oz, it has a simple draft collar and zipper draft tube to seal in your body’s warmth. Plus, there’s a foot vent on the bottom of the bag that you can stick your feet out of if you’re too warm at night. Nothing fancy, but it gets the job done and the price is right.
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Sierra Designs | Amazon
Big Agnes Star Fire UL 0 Sleeping Bag
The Big Agnes Star Fire UL 0 is a highly efficient down mummy bag insulated with 850 fill power waterproof down. It has an oversized draft collar, a half zipper to save weight, a snag-free side zipper, an insulated draft tube, and Pertex Quantum shell to keep you toasty warm on cold nights. Body-mapped baffle construction optimizes thermal efficiency while the ergonomic foot-box construction provides more loft and warmth. Unisex.
Therm-a-Rest Questar 0 Sleeping Bag
Made for frigid backcountry conditions, the Therm-a-Rest Questar 0-Degree Lightweight Down Mummy Sleeping Bag offers comfort features like SynergyLink Connectors that integrate the bag with a sleeping pad while allowing Zoned Insulation to keep fill where it’s needed most. Mummy construction features a cinchable hood, insulated toe pocket, left side zipper and a zipper draft tube and draft collar keep out the cold. Designed to fit both men and women and available in three sizes:
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Backcountry | Amazon
What to Consider When Buying Winter Sleeping Bags
Mummy Sleeping Bag or Quilt?
Under 20 degrees Fahrenheit, a mummy sleeping bag is warmer and more comfortable than an ultralight down quilt. While quilts are popular in the summer, mummy bags are far more breathable when the temperature dips below 20 degrees. They also provide a warm nighttime storage space where you may keep water, filters, and footwear to avoid freezing. This is more difficult to achieve with an ultralight quilt, which is often shorter and narrower in size to reduce weight. Sleeping in below-freezing conditions alters your behavior and necessitates a different set of skills and equipment than three-season camping or backpacking in warmer weather.
Down vs. Synthetic Insulation
Down insulation is more compressible and warmer than synthetic insulation in terms of weight. How much warmer is it? Only 600 fill power down is equivalent to the best synthetic insulation. What about moisture build-up within the bag? It’s doubtful that you’ll perspire enough to drastically impair the insulating value of a down bag if you’re only going out for one or a few nights in sub-zero temperatures. If you’re on an expedition where you’ll be sleeping out in -40 degree temperatures every night for weeks on end, it’s a different story. Even yet, most climbing guides and explorers prefer down-filled sleeping bags to synthetic sleeping bags since down-filled sleeping bags are warmer, pack up smaller, and are lighter to carry.
Waterproof Down vs Non-Waterproof Down
The term “waterproof down” is a misnomer. While so-called down waterproofing treatments help down dry faster if it gets wet from perspiration, most premium sleeping bag manufacturers won’t use them since it diminishes the perceived insulation value of goose down with 800, 850, 900, and 950 fill power.
What is the best temperature rating for winter sleeping bags for backpacking? While there are many variables, a zero-degree sleeping bag is usually a decent starting point because you can easily increase the temperature by 20 degrees by wearing insulated clothing or adding a sleeping bag liner, which can save you money. In milder temperatures, up to roughly 20-30 degrees, a zero-degree bag can be used by opening open the zipper or loosening up the hood and venting it if you’re too hot. In comparison to a minus 20-degree sleeping bag, the weight and packability of a 0-degree sleeping bag is quite reasonable, and it usually does not require the purchase of a larger backpack to carry it.
Best Type of Insulation
You’ll need a down-insulated sleeping bag if you plan on doing any winter camping or backpacking because it’s the warmest insulation available by weight. It compresses well, making it easy to carry. Down fill powers of 800, 850, or 900 are ideal: the larger the number, the better. By weight, a higher fill power down traps more warmth than a lower fill power down. Many people ask if goose down is superior to duck down. All down is graded in the same way, regardless of species. In other words, 800 fill power goose down is just as good as 800 fill power duck down, but it costs more since the supply is limited.
Sleeping Bag Dimensions
It’s normal to sleep with boot liners or boots, water bottles, and other items that shouldn’t freeze overnight, such as water filters. This means you’ll need some extra room in a cold-weather sleeping bag to stow your gear while still remaining comfortable. Some people get a longer sleeping bag to store stuff below their feet in addition to increased shoulder, hip, and foot width. Winter evenings are long, and it pays to be comfortable, especially if you have to sleep with wet, freezing boots.
Must-have Features for Winter Sleeping Bags
At the very least, winter sleeping bags should include a draft collar, zipper draft tubes, and snag-free zippers. Half length zippers, continuous baffles, vents, and even water-resistant down are all nice-to-haves, but you can skip them to save money or because they’re not necessary.
Draft collars are standard on most winter sleeping bags, and I consider them a cold-weather necessity. A draft collar is a tube of insulation that wraps over your chest and neck and locks in the warmth of your sleeping bag. When you move around inside the bag without it, the warm air will flow out around your neck. A down tube that covers the front of your chest is the most basic draft collar. Higher-end bags have a second draft collar that wraps around your shoulders and neck and has extra settings to tighten or loosen it.
Zipper Draft Tubes
Because it’s cold, draft tubes are down tubes that cover the side zipper so your legs don’t come into contact with it. They help keep chilly air out of the bag by blocking the needle holes formed when sewing the zipper to the bag. Most winter bags include at least one zipper draft tube, and some have two, one on top and one on the bottom, that fall into place when you zip up your bag.
Snag Free Zipper
Snag-free zippers keep the teeth of the side zipper from ripping your bag’s outer fabric and spilling its insulation. To keep it away from the down baffles and prevent it from being snagged on the bag’s outer shell, the zipper is frequently surrounded by stiff fabric tape.
Bonus Features for Winter Sleeping Bags
In winter sleeping bags, water-resistant down is a nice to have rather than a need. Most people, in fact, can keep their sleeping bags dry. The presence of wetness on the exterior of your sleeping bag in the morning does not imply that the down inside is damp. It will dry in no time if you lay it over your tent in the sun while eating breakfast.
Baffles that span horizontally across a bag are called continuous baffles. They make it possible to shake the down in the baffles and relocate it to a new spot. If you’re too hot, for example, you can shake the down so it falls down the sides of the bag rather than on your chest. While continuous baffles allow you to tailor the distribution of down to meet your specific needs, many individuals prefer baffles that keep the down in one spot reliably and permanently. There’s one less issue to be concerned about.
Partial length zippers
Partial length zippers are commonly utilized to save weight, but they can limit your venting options, limiting your use throughout a wider temperature range.
Vents like NEMO’s Thermogills or Sierra Design’s Foot Vent can help a sleeping bag’s temperature range, but they’re only one method of doing it. See above for alternate methods to adjust your temperature without buying more gear.
Go Tackle The Cold
Now that you’re armed with possibly way more knowledge about down-filled winter sleeping bags than anyone may need, it’s time to pack it up and head out to the wilderness to give it a go! I personally am a huge fan of Nemo, but since I live in Phoenix and most of my adventures are in warmer weather, I use the Nemo Kayu 15. It’s overkill for many of my trips, but because of the baffling system and its insanely light weight, it’s my go to.