Review: Nemo Tensor Insulated Air Mattress

Insulated Air Mattress
Nemo Tensor Insulated Air Mattress
$200, 13 oz. (regular mummy, not including stuff sack or pump bag)
Sizes: four sizes from 20×72 inches to 25×76 inches

The search for the right backpacking air mattress tends to boil down to two competing objectives: finding a mat with the lowest possible weight without compromising on comfort. And different people will define comfort differently—thus affecting the weight of their air mat choice. But many backpackers and other users may find Nemo’s Tensor Insulated hits a sweet balance between those competing objectives, as I did sleeping on it for eight nights on a nearly 130-mile, August hike through the High Sierra, much of it on the John Muir Trail, and for four nights in early September in the Wind River Range.

On both trips, I slept in the Sierra Designs Cloud 35 and the Therm-a-Rest Hyperion 32 bags and our coldest nights dipped into the 40s F. I also slept on the Tensor Insulated air mat under the stars very warmly zipped up inside the Sierra Designs Mobile Mummy 15° F/-9° C bag on a late September night in the upper 30s in Idaho’s City of Rocks National Reserve. And my wife slept on the Tensor (and in the Mobile Mummy 15° F/-9° C) for a total of four nights on three-day hikes on both the Skyline Trail in Jasper National Park and the Nigel, Cataract, and Cline Passes Route in the White Goat Wilderness of the Canadian Rockies.

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Nemo Tensor Insulated Air Mattress.
Nemo Tensor Insulated Air Mattress.

Three inches thick, the Tensor’s undulating lateral Spaceframe baffles and low-stretch, die-cut trusses to minimize springiness create a nicely cushioned bed with good stability: I flop around during the night but never bounced or rolled off the air mat. To the contrary, even though it’s not one of the thickest backpacking air mats out there, I found it quite comfortable, with hipbones and elbows never bottoming out on the hard ground.

Nemo rates the Tensor Insulated to 15 to 25 degrees Fahrenheit, thanks to its notably quiet PrimaLoft synthetic insulation and a new, continuous TPU film inside to prevent convective heat loss.

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Using the Vortex pump sack to inflate the Nemo Tensor Insulated Air Mattress.
I’m breathing air into the Vortex pump sack to partly fill it, then roll up the sack to inflate the Nemo Tensor Insulated Air Mattress.

Those updates elevated the air mat’s R-value to 4.2, meaning it delivers significantly more insulation from a cold ground than the previous generation of the Tensor Insulated, which was rated 3.5. That means this air mat is now legitimately warm enough for shoulder-season adventures and temps around and below freezing—although you’d probably want a higher R-value air mat for temps well below freezing and sleeping on snow or frozen ground—and Nemo achieved this without the mat gaining weight. The uninsulated Tensor’s R-value also went up, from 1.6 to 2.5, making it more suitable for cool nights but not temperatures dropping near freezing.

At 13 ounces for the insulated regular mummy air mat and a pound packed (including the Vortex pump sack and staff sack), the Tensor weighs in lighter than many competitors with comparable comfort and dimensions; and it measures a compact 3×8 inches/20×7.5cm packed, slightly larger than a liter bottle, taking up noticeably less space in a backpack than heavier air mats.

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The Nemo Tensor Insulated Air Mattress valve.
The Nemo Tensor Insulated Air Mattress valve.

The two-piece Laylow valve, with separate valve flaps for inflating and deflating, make both chores a breeze and deflation almost instantaneous. The Vortex pump sack that comes with the Tensor lets you employ the Bernoulli effect to quickly inflate the mat by blowing a light breath into the open sack and rolling the air into the mat (several times)—much easier than making yourself dizzy blowing air directly through the valve and minimizing moisture entering the air mat. The Vortex sack adds little weight to the package and has a shape and size that makes it a bit faster inflating an air mat than other such pump sacks I’ve used.

Lastly, the updated Tensor’s 100 percent recycled and bluesign-certified, 20-denier polyester fabric on top and bottom is likely not as puncture-resistant as some air mats that use a heavier fabric, but it offers durability that compares with many ultralight models.

The Tensor series comes in four models each in both insulated and non-insulated: regular and regular mummy, both 20×72 inches, and wide (25×72) and long wide (25×76) versions.

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The Verdict

Comfortable, notably quiet, lightweight, and packable, the Nemo Tensor Insulated Air Mattress will appeal to many backpackers and other backcountry travelers who want an ultralight air mat that doesn’t compromise on comfort.


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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.

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2 thoughts on “Review: Nemo Tensor Insulated Air Mattress”

    • Hi Albert,

      I can see why that photo would look confusing and I just changed the caption on it to better explain what I’m doing in that photo, which I’ll elaborate on here. All of these pump sacks work by filling them with air and then rolling them up, thus pushing the air into the air mattress. There’s a scientific principle that fully explains it, but suffice to say that blowing air into that sack and rolling the air into the mattress is far easier than the traditional method of blowing directly into a valve. You can either lightly blow air into the sack or shake the sack open widely and then close its mouth to trap the air before rolling it. In that photo, I’m lightly blowing into the sack before rolling it—not, as I think you mistakenly interpreted (understandably, I suppose), trying to directly inflate the air mat by blowing into the sack without rolling it up (which would never work, anyway).