Ultralight hunting brand Kuiu combines the best materials to build a premium sleeping bag
Down has the highest warmth to weight ratio of any insulating material, but it has one glaring downside: once wet, insulating powers are lost. Covering the down in a waterproof breathable fabric has been done, but condensation gets trapped in humid conditions and the down loses loft and insulating value. Recent innovations in coating the down feathers with water repellent compounds have virtually eliminated this huge drawback. The direct to consumer ultralight hunting brand Kuiu has chosen what they feel is the best of these offerings. Kuiu uses Quix Down from textile industry leader Toray. Quix Down starts at 865 fill power Polish Down, with a 95/5 down to feather ratio. Fill power is the amount of volume in cubic inches that an ounce of down will occupy. Higher values provide more loft and warmth per unit of weight, and an 865 rating is amongst the highest available. This loft rating and down/feather ratio is independently certified through the IDFL, an independent textile quality assurance laboratory, not a common move. Toray treats each down cluster with a nanotechnology driven finish, making them virtually waterproof, preserving loft by protecting against moisture, both from the outside and inside (via condensation).
The down is held in place by vertical baffles with down proof flow gates, allowing heat to transfer from hot to cold over the entire length of the body and preventing horizontal shifting of down due to gravity. A full-length zipper with double pulls allows the foot box to be vented separately if required and allows the sleeping bag to be used as a quilt in warmer conditions. There are baffles around the hood, shoulders and behind the zipper to prevent heat loss through those areas. The cut is more voluminous than most mummy style sleeping bags, and according to Kuiu, this was done to accommodate the larger frame of an average American hunter. This translates to improved freedom of movement within the bag, alleviating some of the claustrophobic feeling that some have with mummy bags. The ultralight shell fabric is Toray’s 12d Stunner Stretch, a down proof two-way stretch material that also adds to the freedom of movement within the bag. This shell is treated with Toray Kudos XR Durable Water Repellent treatment to fend off spills and condensation from the tent or bivy bag.
Kuiu Super Down Sleeping Bags are available in three temperature ratings (all EN certified lower limit ratings): 0, 15 and 30 degrees F, each available in regular and long lengths. My testing sample was the 30° regular version, with an amazing verified weight of 1.5 lbs. The bag fit my 6 foot, 167 lb. frame well, with the aforementioned extra space and stretch a welcome feature. The bag was used in both bivy bags and tents, in conditions ranging from alpine areas of the Pacific Northwest to the arid deserts of Mexico. I found the lower temperature rating spot on when used with an ultralight air-filled sleeping pad and wearing a light base layer. The halo, shoulder and zipper baffles are all substantial, fighting heat-robbing drafts extremely well. The zipper baffle is particularly large but the full-length zipper didn’t snag on the baffle, which is super annoying and common.
Another nice touch is a reflective and glow in the dark zipper pull. The Kudos XR DWR shell finish combined with the water repellent Quix Down resisted an extremely humid inversion in an alpine valley, warding off a ton of condensation in a small tent with no loss in loft. Haphazard treatment hasn’t even nicked the shell fabrics and all components of the bag remain functionally perfect. The bag comes with a lifetime warranty against defects, a stuff sack and storage sack.
During my 30+ years of adventuring, I have had somewhat of an obsession with sleeping bags, a quiver of high-end choices always at the ready. I admittedly had reservations about trusting a brand coming from the hunting world, but this bag has firmly placed Kuiu in my sights as a provider of innovative products that cross over flawlessly into all outdoor adventures. The Super Down Sleeping Bag 30° started with the best ingredients and combined with intelligent design, created a sleeping bag that has become one of my go-to favorites. MSRP: $449.99 regular, $469.99 long. www.kuiu.com