With the promise of a “new benchmark” in the world of products made for sleeping outdoors, this spring Sea to Summit unveiled a line of down-insulated sleeping bags, the company’s first foray into the space. The line, which includes four categories and nine sleeping bag models, is not just another average range — the bags in the series include neat new tech like nano treatments for water repellency, silicone-encapsulated fibers for moisture control, as well as top-quality, 850+ loft European goose down.
Says the company founder, Tim Macartney-Snape, in a document on the bag line, “I’ve owned many different sleeping bags but I’ve never been entirely happy. . . they’ve always suffered a few inadequacies.” Macartney-Snape cites snagging zippers, poorly-fitted hoods, cold spots, “day-to-day growing dampness” of the down, and difficult drawcords as the culpable causes for many bags’ underwhelming performance in the field.
The company’s new sleeping bag line attempts to remedy the above concerns as well as offer a spread of trail- and expedition-ready down bags for a variety of environments.
I tested one of Sea to Summit’s ultra-light models, the Micro MC III, on a recent expedition in New Zealand. It has a “lower limit” temp rating of 28 degrees F, which is based off the EN13537 Temperature Rating System, a European standard for sleeping bag temperature ratings. (Barry Robertson, a representative for Sea to Summit, cited the bag’s 28-degree “lower limit” rating as applying to the lower comfort range for an average adult male.) All this warmth came in a 1.5-pound bag that packed approximately down to the size of a small melon.
In the past, for climbing trips and expeditions, I have long been on the fence in the down-versus-synthetic insulation debate. Down bags are warmer, lighter, and more compressible, but they also require more maintenance on the trail or mountain — if they happen to get wet they become almost worthless. Sea to Summit’s new sleeping bag shell material — the 2D Nanoshell technology, cited as the “lightest, most breathable water-resistant shell” available — would have to seriously stand in and help in New Zealand’s famously rainy environment.
In my test, the 2D Nanoshell tech — which is a proprietary, nano-based dwr (durable water repellent) treatment — did indeed keep the bag breathable while still maintaining water resistance to keep the down insulation inside dry. I have found that moist down tends to be the big negative feature of many bags, as the sleeper’s body moisture eventually turns the whole bag a bit soggy after days of use. It is not at all uncommon, in my experience, for a down bag to sleep much colder at the end of a trip than it did at the beginning.
