Nemo have long been an UOG customer favourite for their lightweight tents but Nemo also make an excellent range of technical sleeping bags. With this in mind we decided to put the 2019 Nemo Kayu 15 to the test on the TGO Challenge.

The Kayu is available in 2 versions the Kayu 30 with a comfort limit of -1C and the Kayu 15 rated to -9C. You never know what the weather might be like in Scotland in late Spring and I prefer not to wear many layers as I end up getting sweaty so opted for the Kayu 15.

The Kayu (men’s) and Aya (women’s) sleeping bags are filled with 800 fill power down that also benefits from a Nikwax water resistant treatment. This combined with a waterproof fabric on the footbox and hood makes it ideal for the damp and humid conditions usually found in Scotland where condensation is almost a given.

Thermo Gills: One stand out feature of the Kayu is the ‘Thermo gills’, something of a Nemo trademark on their high end sleeping bags. These ‘gills’ allow you to vent heat from the sleeping bag without any draughts. This feature contributed to my decision to take the warmer Kayu 15 as I could release excess heat if I got too warm. The zippered ‘Thermo Gill’ vents are positioned on the top of the bag and can be opened or closed to regulate the temperature. They can be easily operated from inside the bag by reaching an arm out. It sounds a bit gimmicky but I found them to work extremely well. There was rarely a night where I didn’t benefit from them. On mild nights I didn’t end up feeling too hot despite the Kayu’s -9C rating.

Body Mapped Fit: The Kayu is fairly slim fitting and the fitted hood accentuates the shape of the sleeping bag making it look slimmer than it actually is. It’s not super roomy sleeping bag like the Nemo Disco but I never felt restricted. It’s heavily tapered with lots of shoulder room and around the feet but slimmer through the hips. I move between my back and side during the night and was still able to move naturally in the Kayu. One benefit of the fit is that it is thermally efficient, there aren’t pockets of air that can get cold and when you move it doesn’t suck cold air into the bag.

Fabrics / Build: The liner fabric is a soft nylon taffeta which feels comfortable against your skin. The shell of the bag is mostly riptop nylon with the addition of a waterproof, breathable fabric covering the footbox and top of the hood. Nemo have recognised that a significant number of customers looking for a lightweight sleeping bag will have a single skin shelter or small tent where condensation is likely to contact the bag at its extremities. It certainly seemed to work for me on a couple of especially damp nights when I slid down the tent and ended up with my feet pressing against the flysheet. A quick wipe over the end of the sleeping bag with a cloth and it was sorted.

Nemo should look to improve the main zip which snags far too easily on the fabric along it. There isn’t much in the way of stiffening along the zip so the fine fabric seems to catch in the zip teeth quite frequently. Once you are aware of this then taking a bit more time does stop it from happening but it is possible to make this area virtually snag free.

The small pocket near the top of the main zip was handy. I often use ear plugs to ensure a good night sleep and they could be popped in here ready for the next night. No more trying to remember where you’ve put them!

Temperature Rating: The Kayu 15 has a lower limit rating of -9C which is always subjective. The coldest night I’ve used the bag it was around -3 to -4C and I was perfectly warm, I actually had the thermo gills open earlier in the night and closed them when it dropped below freezing. It make the Kayu 15 a great proposition as a warm 3 season bag suitable for most parts of the UK from Spring through to Autumn.


The Kayu 15 isn’t the lightest sleeping bag for its temperature rating due to a number of features that are worth the small increase in weight. Thermo Gills do actually make a difference and extend the sleeping bags range making it more comfortable on warmer nights. The addition of waterproof fabric on the footbox and hood makes total sense for UK use where condensation can be an issue. The mummy fit was great for me, enough room where I needed it without excess space which might get cold or need warming up when you first get in. In use it is definitely more comfortable than the picture might suggest. I appreciated the Kayu’s additional features which for me did contribute to a better nights sleep.