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9 Best Sleeping Bag Brands of 2019

JUMP TO A BRAND:  FEATHERED FRIENDSWESTERN MOUNTAINEERING / MARMOT / REI CO-OP / THERM-A-REST / PATAGONIA / ZPACKS / ENLIGHTENED EQUIPMENT / NEMO

There are a huge number of sleeping bag brands out there, catering to all different sections of the market. From budget synthetic sleeping bags for festivals and car camping, through to technical ultralight down sleeping bags for thru-hiking and mountaineering.

In this round up we cover the best sleeping bag brands, focusing on those designed for lightweight and ultralight backpacking.

We focus on sleeping bag brands that are using high-quality goose or duck down and lightweight shell fabrics. These design features help to ensure their sleeping bags have the highest warmth-to-weight ratios, making them the ideal choice for lightweight and ultralight backpackers.

 

Enlightened Equipment are one of my faves — they make both quilts and hoodless sleeping bags.

 

Many of the sleeping bag brands below offer products at a relatively high price point. This is because the manufacturing cost of a high quality down-filled sleeping bag far exceeds that of a synthetic sleeping bag.

However we believe that the unbeatable warmth-to-weight ratio, compressibility and longer lifespan of high quality down makes it the best choice despite the higher cost. The sleeping bags below — if properly cared for — can last a decade or two. Many of the manufacturers listed below also have great customer service, long term warranties, and manufacture their products in the USA.

So here they are, the best sleeping bag brands for lightweight and ultralight backpacking…

If you love this list of the best sleeping bag brands, then you'll likely love reading some of our other gear review pages:


Need to know what to look out for?

Buying a new ultralight sleeping bag can be a relatively stressful task. The main reason being that they are relatively expensive!

But never fear… if you want tips on things to consider before making your purchase, then check out our detailed buying advice at the bottom of the page.

JUMP TO ADVICE: TEMPERATURE RATINGS / INSULATION / FABRICS / DRAFT TUBES & COLLARS / SHAPES, ZIPS & HOODS


Always felt constricted in a sleeping bag?

Perhaps consider checking out our list of the Best Backpacking Quilts.

An ultralight backpacking quilt can be more comfortable and versatile than a sleeping bag, especially in warmer climates and for restless or side sleepers.


FEATHERED FRIENDS

Feathered Friends are an icon of the lightweight backpacking industry. Started in 1972 by husband and wife team Peter and Carol Hickner, they have grown into one of the most popular manufacturers of high-quality down garments for lightweight backpacking and alpine adventures.

Their main line of products are their down filled sleeping bags and garments (including down jackets and pants). They insist on using only the highest quality goose down — in fact all of their sleeping bag product line uses 900 fill power down or above! They also use 100% RDS certified down in all of their products, so you can rest assured that the down in your sleeping bag has been ethically sourced.

Feathered Friends sleeping bags are manufactured at their factory in Seattle, Washington. This ensures that — after almost 50 years of trading — their sleeping bags are still manufactured to the highest quality standards. With good care a Feathered Friends sleeping bag should be able to last you a lifetime… literally. To help you along with that goal Feathered Friends offer a lifetime warranty against defects in workmanship or materials. Pretty epic!

Our Pick: Feathered Friends Lark 10 UL

ISO COMFORT RATING: N/A

FILL POWER: 950+

FILL WEIGHT: 20.0 oz / 567 grams

TOTAL WEIGHT: 31.3 oz / 887 grams

The Feathered Friends Lark 10 UL is an epic sleeping bag for those who want a three-season bag that they can push right to the limits of spring and fall. The Lark isn't a true winter bag, but it is much warmer than most three-season sleeping bags. And weighing in at under a kilogram means this bag is well within reach for the average thru-hiker, or those trying to reduce their base weight without sacrificing warmth and safety.

As a smaller company, Feathered Friends do not send their sleeping bags for independent testing (i.e. their bags are not EN or ISO rated). However Feathered Friends are always pretty conservative with their temperature ratings. The Lark is rated at 10°F by Feathered Friends, which we would consider to be somewhere between the lower limit and comfort rating. We find that the Lark with its 950+ fill power down, hood, full draft tube, and draft collar is warmer than others claiming to be “10 degree bags”.

The footbox on the Lark is fully enclosed and cannot be unzipped. The #5 YKK two-way zipper provides some versatility, since it can be unzipped in either direction (as far as the lower calf). The continuous horizontal baffles also mean that you are able to shift the down to where you need — on top for extra warmth, or below you for less warmth. But if you are using your bag predominantly in milder climates then the warmth of this bag may be overkill.


WESTERN MOUNTAINEERING

Western Mountaineering is another manufacturer that has been around for more than 30 years, and still manufacturers their products in the USA using the highest quality materials.

Western Mountaineering market their sleeping bags as being manufactured with 850 fill power down or higher. However they are known to be conservative with their ratings, and in fact the down they use is predominantly 900 fill power or higher. This ensures that they are only using the highest quality goose down available. And better yet, all of their goose down is ethically sourced.

Most of their sleeping bags use a mummy or semi-rectangular design to maximise weight savings. They use shell fabrics ranging from 7 denier rip stop nylon for the ultralight hiker, through to Gore Windstopper for the extreme alpine adventurer. This variety allows you to find a product that is perfectly dialled in for your intended use case.

As a testament to the quality of their manufacturing process, Western Mountaineering offer a lifetime warranty against defects in workmanship and materials.

Our Pick: Western Mountaineering UltraLite

ISO COMFORT RATING: 25°F / -4°C

FILL POWER: 850+ (more like 900+)

FILL WEIGHT: 16.0 oz / 455 grams

TOTAL WEIGHT: 28.9 oz / 820 grams

The Western Mountaineering UltraLite is a seriously warm bag for 3-season use. But that means we can use it right into the should season and in mid to high elevation environments. It is perhaps too warm for low elevations in mid-summer, but at those times we usually prefer to use an ultralight backpacking quilt anyway.

The UltraLite is manufactured to Western Mountaineering’s highest standard. It comes with all the expected features — like a reliably snag-proof two way zipper to help with ventilation, and a cosy draft collar to help retain warmth. The UltraLite uses an ultralight 12 denier shell and a slim tapered cut to ensure the highest warmth-to-weight ratio. Although the slim cut means that this bag might not be best for side sleepers.

The UltraLite uses continuous horizontal baffles. These mean that you can shuffle down to the places you need it — on top of you for extra warmth, or below you for less warmth. This adds somewhat to the versatility of the bag. The UltraLite is a seriously warm bag, with a pretty high price tag. But it is also the type of bag that will last you a lifetime if cared for properly.

If you are looking for something a little less warm then consider the Western Mountaineering MegaLite instead. If you want a bit of extra width then consider the Western Mountaineering Alpinelite.


MARMOT

Marmot is a brand that has been operating in the outdoor industry since 1974. Their main product line focuses on outdoor clothing, sleeping bags, backpacks and tents.

Marmot is now a subsidiary of a much larger company — Newell — that is involved in the production of a variety of consumer products. Although Marmot are therefore less independent than many of the other smaller cottage companies in our list, they are still reliably producing high quality gear suitable for lightweight backpacking.

Many of the products they design are innovative and use modern materials that offer the best performance — including their sleeping bags! Hence they still remain one of the best sleeping bag brands out there.

Marmot also claim to have an environmentally and socially conscious approach to manufacturing and production. You can read more about their philosophies and policies around sustainability here.

Our Pick: MARMOT PHASE 20

ISO COMFORT RATING: 30°F / -1°C

FILL POWER: 850

FILL WEIGHT: 14.1 oz / 400 grams

TOTAL WEIGHT: 23.3 oz / 660 grams

The Marmot Phase is a well designed sleeping bag made with ultralight shell fabrics and high quality water resistant down.

The shell fabric is a 10 denier ripstop nylon that provides the ideal balance between durability and weight for the lightweight backpacker. The 850 fill power down is treated with Marmots durable water repellent (DWR) treatment which they refer to as “Down Defender”. This helps to protect the goose down from losing some of its loft in damp conditions.

The key upsides of this bag are its small pack size and its awesome hood. This bag compresses down small, much smaller than other bags with similar temp ratings. The hood is designed so that it fits snugly over your forehead, whilst still allowing your space for your mouth to breathe. This means that you can cinch the hood right in on cold nights and still remain comfortable. This allows you to use this bag in temperatures that otherwise might not have been possible. Note that we don’t think this bag is quite as warm as the Western Mountaineering Ultralite (which contains more down fill) but it does come close.

The key downsides of this bag are its zipper and its very slim cut. The full length zipper is very small and tends to snag very frequently. This might be a deal-breaker for some. Hopefully Marmot will rectify this in future models. The very slim cut of this sleeping bag means that it is more suitable for back sleepers than side or front sleeper. Side sleepers in particular will likely find this bag too slim to be comfortable.

Overall the Marmot Phase 20 is a pretty epic sleeping bag for back sleepers who value a good hood and want something highly compressible. If you are looking for a similar design that is slightly less warm then consider the Marmot Phase 30.


REI CO-OP

It may seem strange including a major retail chain in a list of best sleeping bag brands. But — as a brand — REI Co-op design and manufacture some of the best value backpacking gear around. And their sleeping bags are no exception.

Of course, REI do cater to a wide range of outdoor enthusiasts and so offer a variety of sleeping bags that differ in both quality and price. Our interest lies with their higher-end down sleeping bags and quilts that are designed for lightweight backpackers. This includes their:

  • Magma 15 (men’s and women’s) and Magma 30 (men’s and women’s) sleeping bags — made with 850 fill power goose down and a 15 denier ripstop nylon shell.

  • Magma Trail Quilt 30 (unisex) backpacking quilt — made with 850 fill power goose down and a 15 denier ripstop nylon shell.

  • Igneo 17 (men’s), Igneo 25 (men’s), Joule 21 (women’s), and Joule 30 (women’s) sleeping bags — made with 700 fill power duck down and a 20 denier ripstop nylon shell.

In these sleeping bags REI uses quality materials in that provide a good warmth-to-weight ratio. Couple that with the fact that these sleeping bags — especially the Magma models — are thoughtfully designed and offered at a reasonable price point for their quality and REI Co-op makes our list as one of the best sleeping bag brands on the market.

Our Pick: REI CO-OP MAGMA 15

ISO COMFORT RATING: 28°F / -2°C

FILL POWER: 850

FILL WEIGHT: 15.9 oz / 450 grams

TOTAL WEIGHT: 28.2 oz / 800 grams

The REI Co-op Magma 15 is the highest quality sleeping bag manufactured by the REI Co-op brand. It uses 850 fill power goose down, which is almost on par with some of the best sleeping bag brands in terms of quality. The down has been treated to try and increase its water resistance.

The 15 denier inner and outer shell fabric is slightly heavier than some of the ultralight sleeping bag manufacturers. However the 15 denier fabric should provide some additional durability compared to bags made with 7 or 10 denier shell fabrics.

The anti-snag zipper on the Magma works well as does the design of the hood. REI offer the Magma in both a men’s and women’s version. They also offer versions that differ only in their warmth rating, the Magma 15 and Magma 30. There is also some talk of a Magma “0” in the not too distant future, although a release date has not been announced.


THERM-A-REST

In the early 1970’s, Therm-a-Rest developed the first ever self-inflating sleeping pad. It was a pioneering invention that would dramatically increase the comfort of hikers and other adventurers sleeping out in the backcountry. Fast forward 50 years and these days Therm-a-Rest are renowned for their large range of high quality sleeping pads. This includes self-inflating pads, closed cell foam pads, and inflatable air pads. Of course the latter includes their uber-popular line of NeoAir pads.

As would seem the natural next step, Therm-a-Rest have begun to move beyond just sleeping pads. They now sell a line products related your entire sleep system. This includes sleeping bags, backpacking quilts, backpacking pillows, and hammocks. Although their sleeping bags are not as widely popular as their sleeping pads, they are high quality and well designed.

Their “Fast & Light” sleeping bag range offers the best in terms of warmth-to-weight and technical performance. It is therefore the best choice for lightweight backpacking. Their Vesper Quilt is also a great option for lightweight backpacking — you can read about it in our review of the Best Backpacking Quilts.

Therm-a-Rest only use RDS certified down in their sleeping bags. So you can be sure the down in your sleeping bag has been ethically sourced. An additional small feature of Therm-a-Rest sleeping bags is that they come with their patented SynergyLink connecters — these elastic straps allow you to attach your sleeping bag to your sleeping pad, so that it doesn’t slide off during the night (kinda handy).

Our Pick: THERM-A-REST HYPERION 20

ISO COMFORT RATING: 32°F / 0°C

FILL POWER: 900

FILL WEIGHT: 12.7 oz / 360 grams

TOTAL WEIGHT: 20.4 oz / 580 grams

The Hyperion is Therm-a-Rests top offering for the lightweight backpacker. It uses 900 fill power hydrophobic goose down and a 10 denier ripstop nylon shell. The result? A seriously ultralight and ultra-compressible sleeping bag with an awesome warmth-to-weight ratio.

The Hyperion 20 might not be as warm as our favourite picks from Feathered Friends or Western Mountaineering, but it is a lot lighter. Unfortunately Therm-a-Rest only make two versions of the Hyperion though:

  • Hyperion 20 — with an ISO comfort rating of 32°F (0°C) and

  • Hyperion 32 — with an ISO comfort rating of 41°F (5°C).

The new thinner SynergyLink connectors supplied with the Hyperion (left) vs the traditional wider SynergyLink connectors (right).

This means that the warmest of these two bags only has a comfort rating down to around freezing. In that temperature range we would potentially reach for a ultralight backpacking quilt instead of a sleeping bag, since they are more versatile and more comfortable for side sleepers. Nonetheless, if you prefer a sleeping bag over a backpacking quilt, then the Hyperion is an option seriously worth considering.

There are however a couple of points worth noting. First, the cut of the Hyperion is quite slim, making it ideal for back sleepers but not so ideal for side sleepers. Second, there is only a half length zipper on the Hyperion — this provides additional weight savings, but also limits the ventilation that can be achieved on warmer nights. Third, the “anti-snag” zipper is unfortunately a little snaggy. Lastly, the Hyperion uses thinner SynergyLink connectors which don’t work as well as the traditional wider SynergyLink connectors (see the photo inset).

Nonetheless, all these small glitches aside, the Hyperion is an awesome ultralight bag that gives Therm-a-Rest a deserved place amongst the best sleeping bag brands.


PATAGONIA

Patagonia have a long-standing reputation as one of the most socially and environmentally conscious companies in the outdoor industry. On top of that, they make some of the best quality outdoor gear around. So purchasing Patagonia gear is — in most cases — a win on both fronts.

Although the company has been selling outdoor clothing since the 1970’s, it was only in 2017 that they released their first sleeping bag. However the company claims that the design has been in the pipeline since 1972! (Talk about taking time to perfect it!)

Patagonia’s founder Yvon Chouinard reportedly designed and manufactured his own sleeping bag way back in 1972. Being an avid rock climber, Yvon included a centre-front zipper that allowed him to stay tied-in when sleeping overnight on a rock face. Lo-and-behold this is the same design that has appeared on Patagonia’s first sleeping bag.

Patagonia may still be relatively new to the sleeping bag market, but their bags are already amongst the best. As you would expect with Patagonia, all materials including the down are ethically sourced.

Our Pick: PATAGONIA 850 DOWN 19°F / -7°C

ISO COMFORT RATING: N/A

FILL POWER: 850

FILL WEIGHT: Not specified

TOTAL WEIGHT: 32.2 oz / 913 grams

Currently, Patagonia are manufacturing just two sleeping bag models.

The first is the Patagonia 850 Down Sleeping Bag, available in a 19°F or 30°F temperature rating. Note however that these are Patagonia temperature ratings and not ISO ratings — see our temperature ratings advice below for more info. Also note that the 19°F or 30°F models have different length zippers — the half length zipper found on the 30°F model does somewhat limit its versatility.

Their second offering is an “elephant foot” bag designed specifically for alpine use. The bottom half is an insulated down bag, whilst the top half is a thin windproof nylon shell without insulation. The lack of insulation in the top half is because it is designed to be paired with an insulated belay parka.

It is the Patagonia 850 Down Sleeping bag that will be of interest to most. Unless you are planning to only use your bag in summer or warmer conditions, the 19°F model will likely provide the most flexibility for three season use.

The zipper is good in the sense that it opens from both ends, doesn’t snag too much, and the centre-front positioning makes it easier to get in and out of the bag. There is a down baffle along the inside of the zipper to prevent drafts. Unfortunately however there isn’t a draft collar, which we believe would have added comfort and warmth. But the hood on the bag is relatively deep and cinches in nicely to help retain warmth.

For a lightweight sleeping bag, the Patagonia 850 Down Sleeping Bag is relatively wide in the shoulders. This makes it very comfortable but reduces the warmth-to-weight ratio. It also uses 15 denier fabric for both the inner and outer shell, which is slightly heavier than some of the other ultralight sleeping bags on our list. We therefore believe that thru-hikers or others looking to minimise their base weight should probably look elsewhere. But if you are an occasional backpacker looking for a premium sleeping bag that places equal emphasis on comfort and weight then the Patagonia 850 Down Sleeping Bag deserves a look in.


ZPACKS

Zpacks are a US-based cottage manufacturer of seriously ultralight backpacking gear. Their shelters and backpacks are some of the most popular amongst thru-hikers and lightweight backpackers. Although their product line of sleeping bags and quilts may not have quite the same level of popularity as their tents and backpacks, they are nonetheless amongst the best (and lightest) sleeping bags you can find.

Zpacks began in 2005 in the living room of founder Joe Valesko. Joe had set out to thru-hike the Appalachian Trail sporting a bunch of homemade ultralight gear he had sewn for himself. When people on the trail started asking him where he had got it he realised there was a demand for the type of ultralight gear he was making for himself.

The business has since grown from one sewing machine in Joe’s apartment to now fill a production facility in Florida, US. But the philosophy doesn’t seem to have changed. Zpacks still make ultralight backpacking gear that doesn’t sacrifice durability, safety or performance.

All their sleeping bags are filled with 950 fill power water-resistant goose down. All down is RDS certified. Zpacks offer three models:

  • a sleeping bag with a full length zip;

  • a sleeping bag with a 3/4 length zip (their “Classic” model)

  • a quilt (i.e. that uses straps or pad attachments instead of a zip)

All options are available at either 10°F (-12°C), 20°F (-7°C), or 30°F (-1°C) ratings. However these are Zpacks temperature ratings and not ISO ratings. They should be taken as being overly optimistic — we’d suggest adding about 20°F to them to get a more accurate “comfort” rating.

All Zpacks bags are hoodless — honoring their ultralight philosophy! We see this as a benefit. Often conditions are warm enough that you don’t even need a hood. And when it does get colder, you can just wear a warm hat or a separate goose down hood.

Our Pick: ZPACKS 10°F FULL ZIP SLEEPING BAG

ISO COMFORT RATING: N/A

FILL POWER: 950

FILL WEIGHT: 17.8 oz / 504 grams

TOTAL WEIGHT: 25.8 oz / 733 grams

Our pick of the bunch is the Zpacks 10°F Full Zip Sleeping Bag. We think it offers sufficient warmth and versatility to compete with the offerings of top brands like Feathered Friends and Western Mountaineering.

The draft tube on this model ensures that even a restless sleeper can keep out drafts in cold weather. And it is seriously lightweight for the amount of down and warmth it packs in. I’d be happy using this bag down to freezing or just below. But I’d suggest sizing up a length so that you can cinch the top of the bag in snugly around your ears when the temperature drops.

If you want to maximise weight savings then could consider the 3/4 zip option instead. But note that the 3/4 zip model doesn’t have a draft tube. So if you are a restless sleeper you might find cold pockets appearing when the temperature really drops.

Alternatively, if you are planning to use your bag in really warm weather, then a Zpacks Solo Quilt or another backpacking quilt might be a better option. The full length draft tube and amount of down packed into this sleeping bag would be overkill in warmer temps.


ENLIGHTENED EQUIPMENT

Enlightened Equipment began in 2007 as a manufacturer of ultralight backpacking quilts. Founder Tim Marshall started the business as a one man operation — sewing all the quilts himself in his home basement.

Since then his business has grown and now employs more than 50 staff in their facility in Minnesota, US. Although backpacking quilts remain their mainstay, they have expanded their product line to include sleeping bags, rain gear, tarps, and more.

Their sleeping bag line follows the same design principles as their backpacking quilts. In the words of Enlightened Equipment themselves…

“Ultralight. Straightforward. Affordable.”

And it is true. Their sleeping bags are amongst some of the lightest on the market, and devoid of unnecessary features. They are also offered at a very reasonable price for the quality.

Better yet, almost every feature on an Enlightened Equipment sleeping bag is customisable. This includes fabric weights, fabric colors, temperature ratings, down fill power, and footbox options.

The only feature that can’t be changed — and that may not be desireable for everyone — is that Enlightened Equipment sleeping bags are all hoodless. However as a front sleeper I prefer this (unless the temperature is below freezing) — see my discussion of Zpacks hoodless bags above.

Our Pick: ENLIGHTENED EQUIPMENT CONVERT 20°F

ISO COMFORT RATING: N/A

FILL POWER: 850 (950 also available)

FILL WEIGHT: 17.9 oz / 507 grams

TOTAL WEIGHT: 26.5 oz / 750 grams

The Enlightened Equipment Convert is an awesome sleeping bag / quilt hybrid. It includes a pad attachment system that means it can be used in just the same way as Enlightened Equipment's backpacking quilts. Nonetheless it also includes a full length zip, which means it can also be used as an enclosed sleeping bag.

The zippered footbox also adds so much versatility. If you unzip the footbox and loosen the bottom shock cord then the sleeping bag can be laid open flat like a blanket. Alternatively, when the zipper is done up and the bottom shock cord cinched in you can seal out almost any cold drafts (if the temp really drops — e.g. below freezing — you could plug a sock or other piece of small clothing in the central hold at the base of the footbox, but this is almost never necessary).

You’d think that all this versatility would add a lot of weight, yet the specs of this sleeping keep it well within the ultralight category!

There is an array of colours and fabric weights (7, 10 or 20 denier) to choose from. So you can achieve your desired balance of weight vs durability. We’d recommend 10 denier fabric, unless you are you are a serious gram counter (go with 7 denier) or planning to sleep outside of a tent so that durability or water resistance are a major concern (go with 20 denier). You can choose between 850 or 950 fill power down. Higher fill power provides better warmth for weight but is more expensive (see our buying advice below).

If you aren’t interested in choosing your own custom specs, then just go with the Enlightened Equipment Convert Stock. It uses 10 denier fabrics and 850 fill power down.

If you want to save an ounce or two and sacrifice some versatility then consider the Enlightened Equipment Conundrum instead — it has a sewn in footbox. Or to save even more ounces then go with one of the Enlightened Equipment quilts.


NEMO

NEMO Equipment (short for New England Mountain Equipment) was born in the early 2000’s with a desire to make creative and thoughtfully designed outdoor equipment.

Its founder Cam Brensinger had recently graduated from design school… and it shows! NEMO are well known for designing outdoor gear that pushes the envelope with creative features and experimental twists that you won’t find elsewhere.

For instance, a trademark of their down sleeping bag line is the “thermo gills” — essentially two zippered vents along the front of the bag that allow temperature regulation on warmer nights. A number of their models also include a “blanket fold” that is intended to make you feel as if you are tucked in under your comforter at home!

Also if you are a side sleeper and always feel cramped in a mummy bag, then NEMO have a solution for that too. Take a look at their “spoon” shaped bags… the NEMO Riff 15 (men’s) and Jam 15 (women’s) as well as their slightly cheaper and heavier cousins the NEMO Disco 15 (men’s) and Rave 15 (women’s).

The “spoon” bags are designed specifically for side sleepers and their “spoon” shape provides plenty of room at the knees and elbows. This makes them much more comfortable for side sleepers, but also means they are a lot heavier than our favourite pick the Kayu 15 described below (in fact the spoon bags are about 12 ounces heavier than the Kayu 15!)

 

Check out NEMO’s video describing the “spoon” shape, the “blanket fold”, and the “thermo gills”.

 

Many of NEMO’s bags also have a waterproof footbox. This is a feature that would actually be a great addition on many other manufacturers bags! A wet footbox from contact with condensation on the tent wall is a real issue for many taller hikers, myself included!

NEMO also use water-resistant RDS-certified down in their products. They also offer a lifetime warranty against any manufacturing defects. That’s pretty cool!

Our Pick: NEMO KAYU 15

ISO COMFORT RATING: 28°F / -2°C

FILL POWER: 800

FILL WEIGHT: 15.2 oz / 430 grams

TOTAL WEIGHT: 30.3 oz / 860 grams

It might not quite have the specs to compete with some of the top line sleeping bags on our list such as the Feathered Friends Lark or the Western Mountaineering UltraLite. But the NEMO Kayu 15 (or Aya 15 for women) is a pretty worthy contender.

It may well save you a few dollars too — it’s not the cheapest down sleeping bag on the market, but its also not the most expensive.

The Kayu & Aya models are NEMO’s highest performance ultralight sleeping bags. But the total weight of these bags is still heavier than our favourite offerings from other ultralight sleeping bag brands on this list. Nonetheless if you like the idea of “thermo gills” for venting and a waterproof footbox for peace of mind, then the Kayu or Aya might be worth a look in.

Also note that all of the previously described NEMO bags (the Kayu, Aya, Riff, Jam, Disco, and Rave) come in two temperature ratings: the manufacturer rated 15°F models we’ve discussed here as well as a 30°F model for warmer climates.


TEMPERATURE RATINGS

Historically, sleeping bag manufacturers were both inconsistent and over-optimistic with their temperature ratings. This caused two major headaches for consumers:

  1. It made it difficult to know how a sleeping bag would actually perform in the real world.

  2. It made it difficult to compare sleeping bags from different manufacturers.

To try and resolve these issues a standardised rating system for sleeping bags was developed in the early 2000’s. This was initially a European Norm (EN) standard called EN13537. However in 2017 that EN standard was superseded by the International Standards Organization (ISO). The tests involved with the EN and ISO standards are almost identical, so it is possible to compare sleeping bags rated under the older EN standard with newer bags rated under the ISO standard.

The EN and ISO standards both require lab testing of the sleeping bag by an independent authority. A heated lifelike mannequin is placed inside the sleeping bag in a climate-controlled room and monitored over time. Two temperature ratings returned by the test are commonly of interest:

  • Comfort rating: the temperature at which a standard female (or cold sleeper) can expect to sleep comfortably in a relaxed position.

  • Lower limit rating: the temperature at which a standard male (or warm sleeper) might sleep comfortably in a curled position.

We believe the ISO comfort rating is the one you should pay the most attention to. It is the temperature you might realistically want to use your sleeping bag in. Below the comfort rating, you would need to start adding additional warmth using a down jacket for example.

 

Meet Simon, the thermal mannequin used in the ISO testing! Photo credit: Kansas State University Institute for Environmental Research.

 

SIDE NOTE: When it comes to independent standardised temperature ratings don’t be fooled by the sleeping bag name! Many sleeping bag brands use the manufacturers temperature rating in the bag name (e.g. Cosy Cocoon 10). However these are almost exclusively not the ISO temperature ratings!

… BUT NOT ALL BAGS ARE INDEPENDENTLY TESTED

Some manufacturers do not have their bags independently tested and therefore do not provide ISO temperature ratings for their sleeping bags.

Don’t worry though, this is not necessarily because they are trying to deceive their customers! It is because the independent testing is very expensive.

Some smaller sleeping bag brands — including those that may already have a good reputation for being conservative with their temperature ratings (e.g. Feathered Friends, and until recently also Western Mountaineering) — are simply not willing to pay for the independent testing. These manufacturers therefore only provide their own “in house” temperature ratings, which often fall somewhere between a lower limit and comfort rating.

CHOOSE THE RIGHT TEMPERATURE RATING FOR YOU…

Of course, everyone is slightly different. Some people sleep hotter or colder than others, and other factors such as hydration, diet, and exhaustion can massively affect your warmth. This can make choosing the best temperature rating for you quite a difficult task, even with the ISO standard!

When considering temperature ratings, try to tailor your choice of sleeping bag to both: (i) the environment in which you plan to use the sleeping bag, and (ii) whether you sleep “hot” or “cold” relative to other backpackers.

…AND CONSIDER GENDER-SPECIFIC DESIGNS

The EN and ISO standards themselves reflect the fact that, in general, women sleep colder than men. Because of this some manufacturers — e.g. REI and Feathered Friends — offer women-specific designs that are both slightly warmer and have a women-specific cut (narrower at the shoulders, wider at the hips).

If a women-specific design isn’t available, then a good rule of thumb is that a woman might want to purchase a bag that is rated about 10°F warmer than a man might otherwise purchase.

 

For some people, waking up next to frost is just never going to be nice — But a warm sleeping bag can make it that little bit easier!

 


INSULATION

DOWN FILL vs SYNTHETIC FILL

The "warmth to weight ratio" is the main metric that sleeping bag manufacturers are aiming to optimise. Maximum warmth for minimum weight. But without sacrificing too much in terms of functionality and durability.

Goose (or duck) down provides much better warmth for weight and compressibility compared with synthetic insulation.

In fact, the warmth to weight ratio and compressibility of high quality down is so superior that we only recommend purchasing a down filled sleeping bag and not a synthetic filled one.

Down fibres also have a much longer lifespan than synthetic fibres — that is, they will retain their loft for many more years than synthetics.

 

Close up image of a down plume. Photo credit: Feathered Friends.

 

DOWN FILL POWER

Higher quality down has better insulating properties (i.e. provides better warmth for weight) than lower quality down. The metric used to measure the quality of the down is known as “fill power”. Fill power is actually a measure of volume. It is the space (measured in cubic inches) that one ounce of down will occupy. So a higher fill power means that each ounce of down will occupy more space.

More space being occupied = More loft & more trapped air = Better insulating properties!

High fill power goose down is also more compressible. That is, your sleeping bag will pack down smaller when not in use. So for two sleeping bags with similar temperature ratings the one with the higher fill power down will pack down smaller.

Aim for a down bag with the highest fill power. The best sleeping bag brands will use 850 fill power or above, since it provides the best warmth for weight and is the most compressible.

Of course the higher the fill power, the higher price tag! And down is a significant component of the manufacturing cost for high end sleeping bags. So you will have to aim for the highest fill power that falls within your budget.


FABRICS

The use of innovative lightweight fabrics for the shell and liner can provide significant weight savings. Look for sleeping bags made with a ripstop nylon in the range of 10 to 15 denier. This provides enough durability for a bag that is well looked after and doesn’t add unnecessary bulk or weight.

If durability is a concern for you — e.g. you often sleep out on rough ground — then consider a sleeping bag with a slightly heavier outer shell fabric, say around 20 denier.

Most shell fabrics are also treated with a water resistant coating. Sometimes this is a propriety water resistant coating bonded to the fabric — e.g. the Pertex Quantum Pro used for Feathered Friends ultralight range of bags. Whilst other companies simply treat the fabric with a Durable Water Repellent (DWR).

If the shell fabric is simply treated with a DWR, then this will degrade each time you wash your sleeping bag. To maintain water resistance over the long term you will need to eventually reapply the DWR.

In any case, you should remember that a water resistant shell fabric is not the same as waterproof!

A water resistant shell fabric is only useful for preventing things like minor dampness from condensation. Your best defence against a wet sleeping bag is care — endeavour to keep your sleeping bag dry at all times. I recommend keeping it in a high quality dry sack whilst in your backpack during the day.

 

Most modern shell fabrics are seriously ultralight, but still durable and water resistant. Photo credit: Feathered Friends.

 


DRAFT TUBES & DRAFT COLLARS

A draft tube is an extra baffle, filled with down, that runs along the entire length of the bag behind the zipper. It is used to prevent cold air from entering the bag through the zipper.

A draft collar is a down filled baffle along the collar of the bag that stops warmth escaping when the top of the bag is cinched in around your neck.

Most sleeping bags include some form of draft tube and draft collar. However some ultralight sleeping bags exclude these features in order to minimise weight.

If a sleeping bag doesn't have a draft tube, then you can sleep on top of the zip to try and prevent drafts in cold weather. However this isn’t foolproof, particularly if you are a restless sleeper.

If you plan on using your sleeping bag in temperatures below freezing then we recommend purchasing a bag with both a draft tube and draft collar.


SHAPES, ZIPS & HOODS

Depending on your preferences, you may be able to achieve significant weight savings by choosing a sleeping bag with specific design features.

  • A tapered mummy bag will be lighter than an otherwise equivalent (semi-)rectangular bag. Tapered bags are also better at retaining warmth because there is less space for air pockets around your body. All of the sleeping bags we have recommended in this list are tapered bags.

  • Do you need a full zip? Perhaps consider sleeping bag with a 1/2 or 3/4 zip over a full length one. But be aware that you might be sacrificing some versatility by being unable to open up the sleeping bag in warmer weather.

  • A backpacking quilt will generally be lighter than a fully-enclosed sleeping bag and can also be more versatile. We generally prefer using a backpacking quilt over a sleeping bag in temperatures above freezing (32°F / 0°C).

  • Consider going with a hoodless sleeping bag like those manufactured by Zpacks and Enlightened Equipment. As well as providing weight savings they can be more comfortable for front or side sleepers. Personally I hate sleeping bag hoods, except in the coldest weather. I much prefer to use a backpacking quilt or hoodless sleeping bag. I then use a pillow or Therm-a-Rest sheet to protect my face from a sticky sleeping pad and wear a fleece hat if it gets cold.

 

Do you even need that zip? Maybe not! … Perhaps a backpacking quilt would be a better choice, depending on your needs.

 

MORE INFORMATION

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Happy hiking and take care out there in the wild!