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January 2024

Gear Review: Nemo Kayu -9 Sleeping Bag


Guest Authors: Nathan Slater & Sanesh Iyer from @alittlepaddle


With it’s light weight and compact packed size, this bag fits easily into hatches and backpacks. It’s comfortable and durable, but has some design features which make it less versatile than we had hoped. In coastal climates, it’s also not as warm as it’s -9 name would suggest.

Sleeping well is one of the most important ways to sustain a long expedition. Long days in the water and physical exhaustion are more easily managed when you are having warm, dry, and comfortable nights. A complete sleep system includes nighttime baselayers, a shelter, a sleeping mat, and a sleeping bag - the focus of this review. Sanesh and I are writing about a pair of Nemo Kayu -9 bags which we received for use on our sea kayak expedition from Victoria BC to Alaska. Our thoughts are based on our testing during this time (and a couple nights beforehand). We will try to generalize our recommendations to other uses, but mostly focus on the ways this sleeping bag met our needs on expedition.

Shape, cut, and features

I’m just a hair over 6ft tall, so I opted for the ‘long’ version of the Kayu while Sanesh opted for the ‘regular’ version. As it turns out, length isn’t the only difference between these two bags. The long bag seems to have been designed with XL people in mind so while Sanesh’s bag is snug around his broad shoulders, I have lots of wiggle room in mine. Curiously, the main side entry zipper on the long bag is exactly the same length as that of the short version so the ‘foot box’ area at the bottom of the ‘long’ bag extends all the way up to my hip. This is a non-issue when the bag is zipped up all the way, but makes it difficult to use as a quilt (the zipper ends up digging into my lower back rather than being down below my knees as in a standard bag).

The main zipper is one of the features of this bag with which we’re really pleased. It has a plastic cover on it designed to minimize snags as you zip and unzip. It isn’t foolproof, but I’d say is snags about half as much as a standard zipper. This is a welcome feature when fumbling around in the dark trying to zip into bed.

Temperature control on this bag is achieved through the use of a draft collar for heating and a set of ‘thermogills’ for cooling. Nemo has decided to forego the common ‘yoke’ style draft collar which covers the shoulders with a gap for the neck to pass through in favor of a minimal ‘flat’ collar. The result of the minimal collar is that there are still some drafts even with the hood synched. This is only really applicable on the coldest nights, but is a worthwhile consideration if you’re a cold sleeper.

On the cooling side of the spectrum, the thermogills are a neat idea. They are a set of two vertical zippers that open up two ~40cm area in the torso baffles. The idea is that these zones will vent heat and keep you cool. I played with these gills when I first got the bag, but found myself leaving them zipped up for the majority of the time. When it’s been warm at night, I simply lay the bag over me like a quilt without needing to fiddle with the extra zippers.

Possibly the best design choice Nemo made with the Kayu is the inclusion of water resistant fabric on the hood and feet. It does a great job of maintaining loft in the down even when I was touching the damp ends of my tent. Sanesh and I both wish that the entire bag was made of this fabric!

The bag packs easily into a 15L compression dry sack with enough room for sleeping clothes and an inflatable pillow. On expedition, packed size is an important consideration and we’re both pleased with the Kayu in that regard. The bag comes with a lightweight compression sack and a large mesh storage bag.


No tears yet! After over 120 nights of use, the toggles are all functioning well and the main zipper is sliding nicely. The smaller ‘thermogill’ zippers have begun to corrode in the salty air and are sticking, but that is likely because I haven’t been zipping them regularly. The bag does seem to lose around 2-3 feathers per night, but that’s pretty typical of lightweight down bags.

Durability is a huge consideration for us on our expedition because we want our gear to work consistently throughout the journey. We’re happy to compromise on features in exchange for having a product that doesn’t need to be replaced halfway through the trip.


Gear sustainability is a multi-layered question. Build materials and quality, product versatility, and company policy are all important factors.

The Kayu -9 is filled with 800 FP hydrophobic, PFC-free, and 100% Responsible Down Standard (RDS) certified down. It lacks any credentialed sustainability certificates for its fabrics and zippers. The bag also has several features (tall foot box, and flat draft collar) that make it more suited as part of a ‘quiver’ of sleep systems rather than a bag for all occasions. Finally, Nemo has grand visions for company sustainability outlined on their website, but are not affiliated with any third-party certification programs such as B-corporation.

Temperature rating

Temperature rating is our main area of concern with this bag. This problem is pretty widespread throughout the industry so it is worth seeing products in person and testing them if possible before believing stated numbers at face value.

Here’s what we found:

Digging into the temperature ratings listed on the bag, the name’s -9 become a bit confusing. The bags comfort rating is -3*C, its limit rating is -8*C, and its extreme rating is -25*. It's worth keeping in mind that the -9 name seems to be in reference to the ‘coldest you’d ever reasonably want to be in this bag’ temperature rather than a comfortable sleep. In Coastal conditions, I found this bag chilly in anything below 5*C.

As described above, with its roomy cut and lack of a ‘yoke’ style draft collar this bag had some draft issues. I had to synch the drawstring around my face quite tightly to avoid feeling cool air moving throughout the bag.

On our kayak expedition, it was mostly the humid coastal air that gave us grief. It is difficult for a down bag to hold proper loft with the humidity so we found it chilly on nights where the temperature fell below 5*C (most of the first month of the journey). There were only a handful of nights between April and June where we didn’t sleep with baselayers and a sweater inside the bag.

Based on my testing this winter and on our sea kayak expedition, here’s how I would rate the temperature of the bag in humid coastal conditions:

Comfort: 5*C

Limit: -2*C

Extreme: -10*C

It’s worth noting that our concerns with the temperature ratings were not ‘deal breakers’ with this bag. Wearing baselayers and sweaters when it was cool and using the bag as a quilt when it was warm, we slept comfortably for the vast majority of nights on this trip.

Final Thoughts

On long expeditions, durability, versatility, warmth, and fit are the key considerations when looking for a sleeping bag.

Durability is a pretty straightforward consideration - a bag that lasts the trip is infinitely better than one that needs to be replaced en-route.

Sleeping situations vary greatly on a long expedition. On this trip we slept in our Kayus on sailboats, friends’ couches, in hammocks, and in tents. With this in mind, a bag that can seal tightly against the cold and open up as a quilt when it’s warm, and holds loft well in damp and dry conditions is key.

On our trip, weather conditions varied from below 0*C to 15*C, humid damp rainforest to bone-dry beaches, and calm stale air to whipping winds. While the tested temperature ratings of the Nemo Kayu didn’t match the listed numbers, we were pleased overall with the bags ability to keep us comfortable most nights.

Considering the length of our expedition, proper fit of the bag is also critical to ensuring comfort. Every sleeping bag manufacturer offers a slightly different cut and everyone has a different build and preference, so, if you’re considering an expedition of a similar scale, spending time testing a variety of options will pay dividends over the trip.

When searching for a sleeping bag, we recommend spending time considering if a left or right zipper is more comfortable for you, whether you’re looking for a single bag for everything, of a quiver of specialized bags, and whether the cut of the bag is something you’ll feel comfortable in over a variety of conditions and uses. Sleeping well is such an important factor in sustaining a long expedition that finding the right bag is both critically important and deeply personal. Overall, Sanesh and I are pleased with the pair of Nemo Kayu -9 bags which we received for use on our sea kayak expedition from Victoria BC to Alaska.