Is DryLoft on a down sleeping bag worth it?

That’s an excellent question. DryLoft, in effect a “thin” version of Gore-Tex, was introduced about seven or eight years ago. It’s marketing pitch was this: Used over insulating garments or sleeping bags, it would shield the insulation itself (particularly down) against moderate moisture -— a flurry of snow blowing into a tent when the door is opened, that sort of thing. Yet it also would be more breathable than regular Gore-Tex, which many bag and parka makers were then using. That’s an important consideration, as condensation trapped inside a sleeping bag or parka can greatly reduce the effectiveness of the insulation itself.

I’ve always been sort of ambivalent about the stuff, even though I have several pieces of gear that use it. For one thing, it added quite a bit to the cost of an item —- close to $100 for a sleeping bag, for instance. And to me it was effective only in a fairly narrow temperature range -— say, between about 20 to 45 degrees. Colder than, and it still increased the chances of moisture becoming trapped inside a bag, where it could freeze. Warmer, and, well, so what if the bag gets a little damp? DryLoft wasn’t protection against a real soaking, anyway.

Since its introduction, DryLoft has sparked plenty of competition, which I think is why you see it mentioned less often. On the one hand, nearly all bag makers now used nylon or polyester shells that are treated for water-repellency, a process that results in a bag that is more breathable than the DryLoft equivalent, cheaper, and nearly as water-resistant. On the other hand, some makers have introduced bag shells that are MORE water-resistant than DryLoft, the logic being that people who want a water-shedding shell on a bag, want a good one. Feathered Friends, for instance, uses a PTFE material (Gore-Tex is based on PTFE, basically Teflon) it sources from a non-Gore maker, hence saving money, and that is more water-resistant than Gore-Tex. Mountain Hardwear, meanwhile, uses a proprietary coated fabric it calls Conduit, which is essentially waterproof, except for the seams a bag will have.

Myself, I think the best shell is a polyester microfiber that’s treated for water-repellency. Soft, durable, breathable and water-resistant. Western Mountaineering uses such a shell in bags such as the Super Apache MF ($335), a superb 15-degree bag. Interestingly, Western touts this shell as its most “extreme-use” shell, even though it also makes and sells DryLoft-covered bags, which it calls its most “water-resistant” bags. Which is true, but it sounds to me like they really prefer the polyester shells.