Review: Sierra Designs DriDown Backcountry Bed

In the realm of outdoor gear, synthetic insulation has come a long way over the past two decades. Unfortunately, its warmth to weight ratio remains steep. Down, made from the plumage of geese (premium, lightest) or duck (denser, lower cost), is without a doubt the more desirable solution. Ounce for ounce, it’s lighter, warmer, and more compressible and resilient. These are all things that make it a more desirable insulation for gear used on long-haul adventures.

Down does, however, have a few limitations. It’s costly, especially really fine down from mature geese, which is typically labor intensively hand gathered. Unlike synthetic insulation, which traps heat when it gets wet, duck and goose down insulation both quickly turn gear into a heavy burden that’s nearly impossible to dry without a clothes dryer. Until recently, this has led many to make a Faustian Bargain, favoring the convenience of synthetic fill over comfort, and shorter-life over long-term investment.

That will soon be changing due to waterproof down, or more accurately “hydrophobic” down. Sierra Design pioneered the breakthrough product they call DriDown,™ discovering a way to make the natural insulation hydrophobic by applying a “molecular level polymer” to individual down plumes. Several companies quickly followed with their own versions, including Down Décor, which uses a “nano technology” finish to create DownTek.™ Their waterproof down is now being used by an ever-growing list of A-list brands. Two other players in the waterproof down category include Mountain Hardwear’s Q-Shield™ and Nikwax’s version.

Functionality ★★★★★
According to Sierra Designs, in an 80 percent relative humidity environment, an untreated 15°F degree down sleeping bag loses up to 30% of its loft over a period of eight hours. Under those conditions, a bag rated to keep you warm down to 15°F degrees at night, turns into a 30-degree bag by morning, leaving you with chattering teeth and in a exhausted zombie state.

But they don’t just “waterproof” their down. Design elements and technical fabrics help ensure that DriDown bags and jackets retain 98% of their loft—and therefore 98% of the thermal efficiency.

Design and Aesthetics ★★★★★
In the mummy bag category, the Backcountry Bed clearly qualifies as a disruptive innovation. To start, the bag is supremely comfortable because it is zipperless. Enter it via an oval-shaped opening coupled with an integrated down insert (think comforter) that can be tucked in or peeled away, depending on temperature fluctuations. Pull it out of the port and use it like a wrap to give you an extra layer of warmth when the pre-dawn chill sets in. Fold it back away from your body to expose the port and use as a heat release valve. The Backcountry Bed’s molded footbox features a self-sealing zipperless “window,” letting you get some airflow from the bottom up if needed.

Either way, this design gives you plenty of range of motion, allowing you to sleep on your side, back or stomach at different times of the night without getting your knickers in a knot. And there’s a lot to be said about being able to fling a foot or arm out from under the covers to help tame the overheating and humidity that invariably accompanies a night in a mummy bag.

Durability ★★★★★
As the industry leader, Sierra Design worked with third party testers, including SGS North America, Inc., California Down and Feather Testing Laboratory, and International Down and Feather Testing Laboratory to establish test procedures to help set industry standards for comparing the performance of various hydrophobic down insulations. You can learn more at  http://www.idfl.com/downfeather/

Beyond waterproofing, the bag’s catenary (oval) entry port is smaller than the bag is wide with slightly cinching edges that retract inward as you toss and turn, effectively keeping drafts out when you have the comforter tucked in. 20D and 30D polyester Ripstop shells (depending on model) paired with a 30D polyester Taffetta lining gives this bag a durable whisper-quiet exterior and a silky, comfy, no-snag interior.

Value ★★★★
Any good (and spendy) investment has a level of risk, but with DriDown, the odds are in your favor. If you’ve had the experience of dealing with a wet down-filled bag while out in the sticks, you can quickly calculate that this is an investment that pays considerable dividends over a lifetime of use.