Review: Sea to Summit Ether Light XT Insulated Air Mattress

Insulated Air Mattress
Sea to Summit Ether Light XT Insulated Air Mattress
$199, 17.3 oz. (regular)
Sizes: five unisex and two women’s-specific sizes

What makes us sleep so well in the backcountry? I contemplated that question after numerous, very peaceful nights of deep slumber on a river trip and three backpacking trips. Certainly, the deep quiet and being outdoors matter. But I must give a nod to the comfort of Sea to Summit’s Ether Light XT, my bed for all those nights—an air mat with an interesting back story of the technology behind my blissful nights on the ground.

I tested the regular Ether Light XT while backpacking four nights in the Pasayten Wilderness in September, two nights in the Wind River Range in August, four nights in The Maze District of Canyonlands National Park in March, and on five nights beside the gently whispering Green River on a rafting and kayaking trip through Desolation and Gray canyons in June.

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Sea to Summit Ether Light XT Insulated Air Mattress
Sea to Summit Ether Light XT Insulated Air Mattress

A fat four inches/10cm thick, the Ether Light series of air mats incorporates the brand’s Air Sprung Cells, made with a matrix of interconnected air chambers that individually conform to your body. Mimicking a pocket-spring mattress in the way they distribute your body weight and prevent hipbones or shoulders from bottoming out on the hard ground, those cells create a sleeping experience that feels more like a bed than lying atop a big, flat balloon.

The Air Sprung Cells also use internal TPU fabric loops to bind the top and bottom layers of shell fabric, enabling more spacing between cells and more air pockets, all of which translates to more cushioning and less weight. At 21.5 inches/55cm wide at the shoulders and 16.5 inches/42cm at the foot, the regular Ether Light XT provides a bit more width than standard regular-size air mats—I never felt like I was on the edge, about to roll off. The six-foot/184cm length is standard for regular-size backcountry air mats.

Considering its dimensions, the Ether Light XT is relatively light at barely more than a pound in the regular and measures 4.5×9.5 inches/11x24cm packed, slightly larger than a liter bottle.

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Sea to Summit Ether Light XT Insulated Air Mattress
Sea to Summit Ether Light XT Insulated Air Mattress

The mat features two types of insulation: Exkin Platinum, a quiet, non-woven fabric with a metalized layer that reflects the body’s radiant heat; and Thermolite, a hollow-core insulation that lofts inside the mat to prevent convective heat loss, giving the Ether Light XT’s five unisex sizes an R-value of 3.2, warm enough for three-season trips in the mountains. The two women’s-specific sizes are slightly wider and have additional Thermolite insulation, giving them a 3.5 R-value.

In The Maze District in the first week of March, three of our nights had lows ranging from the high teens to the mid-20s Fahrenheit and I remained entirely warm and comfortable—even sleeping in a 30-degree bag (the freakishly warm and ultralight Feathered Friends Hummingbird)—clearly at least in part because the Ether Light XT provided solid insulation from a cold (though not frozen) ground.

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Sea to Summit Ether Light XT Insulated Air Mattress Airstream Pump stuff sack.
Sea to Summit Ether Light XT Insulated Air Mattress Airstream Pump stuff sack.

The two-piece valve has separate ports for inflating and deflating, and deflating takes literally a few seconds and makes for a much easier and faster method of packing up the air mat.

Sea to Summit’s Airstream Pump stuff sack employs the Bernoulli effect to efficiently inflate the mat by blowing a light breath into the open sack and rolling the air into the mat—a much easier experience than making yourself dizzy blowing air directly through the valve. S2S says you use 80 percent less breaths, a time and energy saver that also minimizes the amount of breath moisture entering the mat. I’ve always found air mats vastly easier to inflate using a stuff sack in this way. The Airstream stuff sack opens at both ends—one for the bag for inflating, the other end for the mat itself.

I found it requires filling and rolling the Airstream Pump stuff sack eight or nine times to inflate the Ether Light XT fully—which can feel a little tedious. I substituted the larger and faster Exped Schnozzel PumpBag UL bag ($39, 2 oz.) and only had to fill and roll it three times. The Schnozzel can double as an ultralight stuff sack for clothing, too.

The 30-denier and 40-denier face fabric is more durable than some air mats and features extruded lamination and an anti-microbial treatment to inhibit fungal growth inside the mat, both features helping to extend the mat’s life. The Pillow Lock consists of non-stick patches applied after purchase (peeling and sticking them into place where indicated on the mat) that hold a pillow in place while you’re sleeping.

Sea to Summit’s Ether Light XT Extreme insulated air mat ($200, 1 lb. 9 oz.) has more insulation, boosting the R-value to 6.2, for use in sub-freezing temps.

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Sea to Summit Ether Light XT Insulated Air Mattress

Weight-to-Performance Ratio

The Verdict

Extraordinarily comfortable and still fairly lightweight and packable, the Sea to Summit Ether Light XT Insulated Air Mattress will appeal to many backpackers and other backcountry travelers who like their wilderness with a chaser of solid sleep.



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See all of my reviews of air mattresses, backpacking gear, and sleeping bags at The Big Outside, and my articles “Pro Tips for Buying Sleeping Bags” and “10 Pro Tips: Staying Warm in a Sleeping Bag.”

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Whether you’re a beginner or seasoned backpacker, you’ll learn new tricks for making all of your trips go better in my “12 Expert Tips for Planning a Backpacking Trip,” “A Practical Guide to Lightweight and Ultralight Backpacking,” and “How to Know How Hard a Hike Will Be.” With a paid subscription to The Big Outside, you can read all of those three stories for free; if you don’t have a subscription, you can download the e-guide versions of “12 Expert Tips for Planning a Backpacking Trip,” the lightweight and ultralight backpacking guide, and “How to Know How Hard a Hike Will Be.”

NOTE: I tested gear for Backpacker magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See The Big Outside’s Gear Reviews page for categorized menus of all my reviews and expert buying tips.

—Michael Lanza

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