What is an Ultralight Sleeping Bag

RogueSurvival.co is a participant in the Amazon Associates Program. This post also contains affiliate links. Which means if you purchase something using our link, we’ll recieve a small commission. Read disclaimer.

It’s time to get another sleeping bag and you’re seeing these sleeping bags called ultralight sleeping bags. Is this just a fancy term that companies are using to sell more sleeping bags, or is there something special about these sleeping bags? What material is used in an ultralight sleeping bag? What’s the average price of an ultralight sleeping bag? Don’t worry, we’re going to be answering all these questions in this article!

In short, ultralight sleeping bags are very lightweight sleeping bags, hence their name ultralight sleeping bags. They’re designed to be lightweight, most are under 2lb (0.9 kilos), so backpackers can decrease the overall weight of their pack. Ultralight sleeping bags are usually made of down or synthetic insulation.

What material is an ultralight sleeping bag made out of?

Ultralight sleeping bags are made out of either down or synthetic insulation of some kind. Synthetic insulation is usually made out of polyester. These materials are ideal for ultralight sleeping bags because of how little space the material takes up while still being able to keep you warm. And like we went over earlier, these sleeping bags are designed to be thin to help cut down the weight of a backpacker’s backpack. Here’s a quick rundown on these two different materials.


You’ve probably already heard of this material at some point. But in case you haven’t, it’s a natural occurring insulation found on ducks. Down, contrary to what a lot of people think, is not duck feathers. Instead, down is the light fluffy coating found beneath the feathers of ducks and geese. But why is down so warm? Well, down creates what is called, high-loft clusters. These special clusters trap air and body heat, making for an extremely warm material.

And since down offers such an extreme warmth-to-weight ratio and can easily be compressed into smaller sizes, it is considered one of the most effective insulators out there. However, you must know that not all down is created equal. Here’s a quick rundown of what I mean.

Simply put, some down offers more effectiveness than others. This effectiveness is measured by how many cubic inches one ounce of down can fill. The term for this is called, fill power. A typical range is around 450 to 900, with 900 being the warmest and also the lightest. However, down with that high of a fill power is also the priciest. If you’re going to be looking for a good ultralight sleeping bag, keep in mind that down sourced from mature geese is the warmest, however, it’s also the most expensive. While on the other hand, down sourced from ducks is a bit less expensive, however, it doesn’t have as much fill power, making it not as warm.

However, even though down is a very effective, warm material that backpackers, campers, and hikers love to use. It does have one very big downfall. And that is the inability for down to repel moisture. When down gets wet, it loses it’s ability to give proper insulation. And, to make matters worse, when down gets wet, it’s also very slow to get dry. So even though down is very warm, and can be packed easily, just don’t get it wet! This brings us to the next material, synthetic insulation.


Synthetic insulation, which is usually made out of polyester, is designed to mimic all of the awesome features that are found in down such as the extreme warmth, and the ability to compress down into small sizes, while at the same time being able to do so when wet.

Another way that synthetic insulation overtakes down is the price tag. Usually, down has more of a premium price tag, so if you’re looking to get an ultralight sleeping bag that is still extremely warm but don’t want to spend the extra money for down, synthetic insulation is a good choice.

While not all down is created equal, not all synthetic insulation is created equal as well. If you’re going to be purchasing an ultralight sleeping bag with synthetic insulation, make sure you know the difference between short-staple or continuous filament.

Products with short-staple insulation feature short strands of fine-denier filaments that are densely packed to minimize the total amount of heat lost. The term filament is referring to the synthetic material. This makes products, such as ultralight sleeping bags, feel very soft and flexible, much like down-filled products. One downside to short-staple insulation, however, is it’s a bit less durable than continuous filament and the insulation can move around to create cold spots.

Continuous-filament insulation on the other hand, uses a thicker filament that is much loftier, stronger, and durable. But since the material is thicker, products with continuous-filament are stiffer and don’t compress as well as short-staple insulations. However, since continuous-filament stays in place, contrary to short-staple insulation, it doesn’t create cold spots in your sleeping bag.

Another thing to keep in mind about synthetic insulation is that it has a slightly higher weight-to-warmth ratio than down. Simply put, if you have a down-filled sleeping bag and synthetic insulation filled sleeping bag that are both equally warm, the synthetic insulation filled sleeping bag will be a bit heavier than the down-filled sleeping bag. If you’re serious about getting your pack as light as possible without decreasing the quality of you’re ultralight sleeping bag, then a down-filled sleeping bag is what you’re going to need.

Which Material is Better? Down vs. Synthetic Insulation

It really comes down to the environment that you’re in, the quality that you need in your sleeping bag, and the price that you’re willing to pay. If you’re just going to be going to a nearby campground for New Years, then you don’t need to get a super expensive ultralight sleeping bag with the most premium down inside. However, if warmth is a major factor in how you choose a sleeping bag, then you might want to think about paying a little extra more for a premium ultralight sleeping bag filled with high quality down. On the other hand, if you’re backpacking into a warm, damp environment, then you might want to think about getting an ultralight sleeping bag filled with synthetic insulation since it is better at repelling moisture.

How much does an ultralight sleeping bag weigh?

The average weight of an ultralight sleeping bag is around 1-2lb (.45-.90kg). However, the weight of an ultralight sleeping bag varies by the intended use, the style of the sleeping bag, and the materials that were used to manufacture the sleeping bag.

Here’s a brief rundown of some popular ultralight sleeping bags and their weight, in order from lightest to heaviest.

Ultralight Sleeping BagWeightPrice
Sea to Summit Spark SpI 4012.4$349
Marmot Phase 3018.3oz$399
Western Mountaineering Summerlite19oz$410
Feathered Friends Flicker 40 UL19.1oz$364
Enlightened Equipment Revelation 2020.9oz$300
Montbell Down Hugger 80024oz$439
Hammock Gear Burrow Econ 2025oz$180
REI Co-op Magma 10 Sleeping Bag30oz$349

Average Price of an Ultralight Sleeping Bag

Ultralight sleeping bags can cost as little as $150 or as much as $500+. Like we went over a little bit when talking about the different materials found in ultralight sleeping bags, the price will greatly depend on the sleeping bag’s materials. However, more determining factors include the size of the sleeping bag and it’s warmth rating.

So for the best average price, we took the prices from 19 of the most popular ultralight sleeping bags and took the average of those prices. We found that the average price for a good, quality sleeping bag will cost around $342. (SOURCES: source 1, source 2.)

If you’re not that thrilled about spending over $300 on a sleeping bag, don’t worry, here are a few inexpensive options:

Hammock Gear Burrow Econ 20 – $140

This ultralight sleeping bag was rated by OutdoorGearlab.com as the best sleeping bag when on a tight budget, read their full review here. One of the ways this sleeping bag is able to come in at such a low price point is because it is made out of duck down, instead of goose down. And like we went over above, duck down is less expensive than goose down because it’s not as warm.

While this sleeping bag has great quality for the price, there are two things specifically where it is noticeably different from premium ultralight sleeping bags. First, it isn’t as warm as other sleeping bags it’s size, this is partly because of the duck down. And second, the bottom of the sleeping bag (the foot end) doesn’t seal very well.

Mountain Hardware Hyperlamina Flame – $240

View the current price on Amazon.

This ultralight sleeping bag is an example of one that uses synthetic insulation. This sleeping bag also features a mummy-cut sleeping bag with a face gasket and single center half zip. Another cool feature is the ergonomic draft collar that prevents the escape of warm air from inside the sleeping bag. There’s also a comfortable foot box that gives you a natural foot position.

The downside to this sleeping bag is the weight. Coming in at 2lb and 12.1oz, this makes it one of the more heavier ultralight sleeping bags.

5 Best Ultralight Sleeping Bags (5 Examples Compared)

There are a ton of different ultralight sleeping bags on the market. This can make choosing one a confusing and stressful task, but don’t worry, because in this section of the article, I’m going to be going over 5 of the best ultralight sleeping bags that you can take with you on your next backpacking trip.

Here’s a quick rundown of the top 5 ultralight sleeping bags:

NameDown or SyntheticWeightWarmth RatingPrice
Feathered Friends Flicker 40 UL950+ Goose Down19.1oz20-40°F $364
Western Mountaineering
850 Down Fill19oz 32°F $410
Zpacks Solo Quilt900+ European Goose Down20oz20°F $339
Sea to Summit Spark SpI 40850+ Goose UltraDry Down™12.4oz40°F $349
Marmot Phase 30850 fill with Down Defender treatment18.3oz30°F $398

Feathered Friends Flicker 40 UL

View the Feathered Friends Flicker 40 UL here.

This ultralight sleeping bag and the Western Mountaineering Summerlite sleeping bag below are arguably two of the best ultralight sleeping bags on the market. However, this one is first on the list for a few reasons. First, this sleeping bag is filled with 950+ Goose down, which if you’re looking for a high-quality sleeping bag, we know that goose down is the way to go. In addition to that, it’s a little less pricey than some bags of the same quality, this bag comes in at around $360. This sleeping bag also has a Pertex® Endurance® UL water-resistant and breathable laminate shell. This will help in keeping the water away from the down. This sleeping bag also has a full-length zipper and drawcords that enclose both the foot box and the neck collar allowing you to zip and cinch this quilt up like a hoodless mummy as well as completely opening up the sleeping bag so that it can act as a blanket.

Western Mountaineering Summerlite

View the Western Mountaineering Summerlite here.

This sleeping bag is the runner up to the Feathered Friends Flicker 40 UL. What sets this sleeping bag apart from other sleeping bags is how light it is even while being a full hoodie mummy sleeping bag. In fact, this sleeping bag weighs less than the Feathered Friends Flicker 40 UL. However, if you’re a very active sleeper, for example, you move around a lot in your sleep, then you might not like this bag. This bag fits a bit tighter than other bags. This bag is also a bit expensive for the features that it offers.

Zpacks Solo Quilt

View the Zpack Solo Quilt here.

This sleeping bag offers multiple sizes to choose from including slim, standard, and broad. It also features an enclosed foot box that will keep your feet from popping out and you can either clip the sides of the quilt at the center to your sleeping pad with an extra strap or tuck them under you. However, this sleeping bag doesn’t feature a hood, so you will need to go a size up if you want to pull it up around your ears. This sleeping bag is also a good fit for people who move around a lot in their sleep.

Sea to Summit Spark SpI 40

View the Sea to Summit Spark Spl 40 here.

This sleeping bag is the ideal sleeping bag for backpackers who truly go ultralight with their gear. This sleeping bag is one of the lightest sleeping bags on the market with a weight of only 12.4oz! The Spark also comes with a compression stuff sack than shrinks this down to about one liter of space. Sea to Summit made this sleeping bag to be so compressible by stripping nearly everything off this hooded mummy bag. There’s no draft collar or tube, only a half zipper, and the baffles are sewn through the shell fabric. However, since this sleeping bag is so light, it does have it’s drawbacks when it comes to warmth. While it’s warmer than some competing sleeping bags, it’s not the warmest sleeping bag on the market either.

Marmot Phase 30

View the Marmot Phase 30 here.

If you go camping or backpacking in wet conditions, then you might want to think about picking up the Marmot Phase 30. Marmot, along with quite a few other companies, is beginning to use a material called, “hydrophobic down.” This down is treated with a DWR (durable water repellent) coating to repel water. Marmot claims that their Down Defender treatment allows their down to stay dry longer, maintain more loft, and dry out quicker than untreated down. This makes for a sleeping bag that is able to offer the benefits of down while being able to withstand wet conditions. However, the Marmot Phase 30 isn’t the warmest sleeping bag out there. In fact, it’s recommended that if you’re going to be camping at around 30F or so, that you switch this sleeping bag out with it’s younger brother, the Marmot Phase 20.

So that was a quick rundown on ultralight sleeping bags. Hopefully, you now feel more confident than ever when choosing a good ultralight sleeping bag! If you found this article helpful, be sure to share it!

You may also like…

Pin It on Pinterest

Share This