[This review has been updated to include information about the Sea to Summit Ultralight Insulated Mat.–Ed.]
MSRP: $89.95-119.95 (depending on size)
I tend to be leery of pure air mattresses. With no foam to insulate me from the ground and to provide extra cushion and stability, they can present a few issues. For starters, they either require some kind of air pump or they take forever (and a headache) to inflate by mouth. The mats I’ve tried in the past also weren’t very stable to lie on–the air in the pad would shift around whenever I changed position. Moreover, the material was either heavy-duty to prevent punctures, or else so light that a single prick from a pine needle could be all it took to put me on the bumpy ground for the rest of the trip.
It should be noted first-off that the Sea to Summit Ultralight Air Mat is intended for warm, summer conditions because it doesn’t have enough insulation to protect your body heat from getting sapped by the cold, the frost or the snow. It has an R-value (a measure of thermal resistance) of only .7. But Sea to Summit also makes an Ultralight Insulated Mat with an R-value of 3.3, which the company has labeled as a 2.5-season mat (with a weight of 16.9oz./479g). An article on the Therm-A-Rest website that explains R-values reports that generally three-season mats are those with an R-value of at least 2.1 and winter mats have an R-value of 3.3 and range to more than 5, so the Sea to Summit Ultralight Insulated Mat could fare slightly better in cold conditions than what the company suggests.
Nonetheless, the Sea to Summit Ultralight Air Mat is a great option to have in my gear closet because it’s comfortable, light (13.9 ounces/394 grams), compact (it compresses down to a size roughly equal to that of a large hoagie sandwich, or as the company reports, a “burrito with double meat and guac”) and is relatively durable.
Next, about the comfort, since that’s what it all comes down to: in this regard, the Sea to Summit Ultralight competes with the much bulkier and heavier air mattresses I’ve used. I can honestly lie comfortably on my side on this mat–that is a sentence I never thought I’d write about a backcountry pad, because “ultralight” often translates as “ultra thin,” and thin padding doesn’t cushion the pelvic bone very well when you’re sleeping sideways. This Ultralight pad however, which is 2 inches thick when inflated, has a conical grid that adds depth to the cushion and also stabilizes the air so that it doesn’t shift around as you move on top of it. These “Air Sprung Cells” are a trademark design by Sea to Summit, which says on its website that the Cells–“hundreds of small interconnected chambers”–were “inspired by the hundreds of springs found in a modern pocket sprung mattress.” Well, it works. For about the last decade or so when I’ve had the luxury of packing for maximum comfort, I’ve often doubled up an air mattress with a foam pad underneath to ensure better sleep. On the Ultralight Air Mat, I’ve slept just as well on the single mattress, maybe even better since my hips don’t dig into the ground. Another bonus about the Air Sprung Cells is that the conical depressions provide pockets that collect any sand and grit that would otherwise be in direct contact with my body, as has always been the case whenever I camp in the desert or on a beach with a mat that has a flat surface.
Durability: the Sea to Summit Ultralight Air Mat is made with a “40-denier face fabric,” which the company website touts as “the strongest face fabric and laminate available in a backpacking air mat.” To give that some context, keep in mind that 20-denier is a typical strength for many of the nylons used for backcountry soft goods. And for comparison, the Therm-A-Rest NeoAir Mat is made with a 30-denier nylon. I’m still inclined to be cautious about where I set the Sea to Summit Ultralight Air Mat down, but I tested it in a couple of dry alpine meadows where there were more pricklies than a person might initially think (sometimes it can be difficult to find ground that isn’t layered with broken twigs, gravel, thorny brush and clumps of dry, pokey grass). In these situations I cleared out the obvious puncture hazards but there was no avoiding them all. The mat held up fine. But it does come with a patch kit, just in case.
Now, about the matter of inflation: it’s a little goofy and took some getting used to…. Another advantage of mats with interior foam is that they tend to self-inflate as the foam expands when the mat is unrolled, and the foam also means much less air is needed to inflate it. Sea to Summit has overcome this disparity with a bizarre pump-sack system. The original pump-sack design was a small stuff sack that looks like a tiny accordion; it has a plastic nozzle that snaps into the Air Mat’s valve, and the mat was inflated by pumping the accordion with your hands. The new design seems even goofier, but its use becomes more practical and efficient after some practice. It still has a nozzle that snaps into the Air Mat’s valve, but it has almost no other plastic parts otherwise. You inflate the mat by blowing a few breaths into the top of the stuff sack to get it to expand and billow with air, and then you quickly close the top and squeeze the captured air into the mattress. After a little practice, I could completely fill the mattress with three iterations in less than a minute. A bit strange to me, but it sure beats hyperventilating to fill the mattress with my own breath. To aid the process further, the Air Mat’s “multifunctional valve” has one opening that couples with the nozzle of the pump sack and only allows air to pass through in one direction, so you don’t lose any progress during inflation, and then another part of the valve can be opened to deflate the mattress quickly.
I look forward to spending many more nights under the stars with the Sea to Summit Ultralight Air Mat!
Alpinist Digital Editor Derek Franz started backpacking with his dad when he was 7 years old. Twenty-eight years later, he often wakes up stiff and appreciates a nice ground cushion more than ever.
Ultralight (13.9 ounces/394 grams)
Effectively pads the ground with Air Sprung Cells that give the mat a depth of 2 inches
Inflates efficiently with a pump sack
Pump sack system takes some practice to master
Not ideal for inflating without a pump sack