Nemo Kayu Sleeping Bag

The Nemo Kayu 15 is the men's version of their most technical ultralight sleeping bag series. Fret not ladies, there is a women's version called the Aya as well with all the same features but tailored specifically for women. Both sleeping bags come in two lengths and two temperature ratings, offering flexibility for any ultralight adventure.

Nemo achieves optimal thermal efficiency in the Kayu 15 by means of aggressively tailored patterning. A contoured hood, body-mapped tapered core, and form-fitting foot box maximize the warmth to weight ratio without compromising comfort. These features result in an ideal fit and smallest possible packed size.

The shell is made with a 20D Nylon Ripstop materials with 40D Nylon Ripstop OSMO at the foot box and hood which is Nemo’s own waterproof fabric designed for extra breathability and enhanced waterproofing. The liner is 30D Taffeta Nylon for a plush, luxurious sleep experience, and is finished with a DWR coating.

Thermo Gills locate on the top of the sleeping bag which are essentially zippered vents in the core of the bag that allows for thermo-regulation without cold drafts. These consist of two super-low-profile zippers located at the chest that create space between baffles for venting body heat. 

A full-length zipper runs down the left side of the bag and is lined with an anti-snag draft-tube. On the Aya (the female version of the Kayu), the zipper is located on the right, so that the two bags can be joined together.

On the right side of the hood, a single drawcord controls the mummy hood opening.

The bag's insulation is 800 FP, RDS certified, water-resistant down. What all that means is that superior loft is maintained even if the bag becomes wet, and that the down used comes from a supply chain that is held to the highest industry standards in terms of both ethics and sustainability. The insulation is treated with Nikwax, a leader in waterproofing that is safe for both the user and the environment.

Incredibly all these features can be stuffed into the included compression sack, or stored long term in a large storage bag. The only thing that won't fit in the bags is the Lifetime Warranty.

Shell: 20D Nylon Ripstop with a DWR finish
Liner: 30D Taffeta Nylon with a DWR finish
Foot Box and Hood: 40D Ripstop Nylon Osmo™ with DWR finish
Fill Type: Down

• Thermo Gills
• Stash pocket
• Tailored patterning with a body-mapped tapered core
• Water-resistant down
• Full-length zipper
• Lifetime Warranty
• Compression sack and storage bag included

Nemo never ceases to impress with their gear which offers technical designs features not seen elsewhere in the market, and they do this without charging an arm and a leg for it. The Kayu men’s sleeping bag hosts all the features you would look for in an ultralight mummy bag. 

Stash pocket? It’s easy to access, right at the top of the zipper by your head. It’s also large enough to put a phone or headlamp in, and the zipper is so low profile that I actually found it sort of difficult to find. 

Compression sack and storage sack? Both are of excellent quality. 

Water-resistant? The shell, liner, and down are all treated in order to keep you dry. They even added materials with enhanced breathability and waterproofing to the foot box and hood so moisture is kept away from key areas.

Dedicated ventilation? Check! I can’t say I’ve ever seen ventilation of this style in a sleeping bag. It makes a lot of sense to me, and much like the stash pocket zipper, the Thermo Gill zippers are so low profile it will probably take you a minute to find them your first time.

Comfortable and packable? I find many ultralight mummies to be a little bit constrictive, but I found the Kayu to be surprisingly roomy. Even with this comfortable roominess, it still packs down to an impressively small size.

Warmth to weight ratio? Ok, here is where the Kayu falls short of industry-leading bags. At 860g, the bag offers a temperature rating of -9C. While this is quite good, when compared to Gear of the Year winners Sea to Summit Spark IV and Mountain Hardwear Ghost Whisperer, it doesn’t quite keep up. The Spark IV offers a rating of -15C and weighs only 20g more, while the Ghost Whisperer weighs 80g less it is rated for -7C. These bags specs books end the Kayu, but their superior fill power means they will have an increased warmth to weight ratio.

Where the Kayu Sleeping Bag really takes the cake, is the price. While offering more features than either of the formerly mentioned bags, Kayu keeps its price tag low.

Bottom line, if you’re looking for a 3 season bag without breaking the bank, Kayu will not leave you disappointed and if you need a great two-person tent to pair it with then have a look over our review of the Nemo Hornet Ultralight 2P Tent here.