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55933Field Report: Big Agnes REM Insulated Air Core Pad--Rick

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  • Rick D.
    Aug 1, 2004
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      Big Agnes Insulated Air Core Inflatable Sleeping Pad
      Field Report

      Product Information

      Name: Big Agnes Insulated Air Core Inflatable Sleeping Pad
      Model: 20x72x2.5 mummy pad
      Maker: Big Agnes Inc.
      Year of manufacture: 2004
      Product Type: Insulated three-season backpacking air mattress
      Options: None available
      Ships with: Stuffsack; repair kit (patches, glue, valve and o-ring);
      hangtags; brochure
      Size tested: 20x72x2.5
      Measured dimensions (inflated): 19.5 x 71.5 x 2.5 inches (49.5 x
      181.5 x 6.5 cm)
      Measured dimensions (deflated, folded and rolled for storage): 9.5 x
      4 inches (24 x 10 cm)
      Specified weight: 20 oz (567 g)
      Measured weight: 18.6 oz (527 g)
      Weight of stuffsack and repair kit: 1.0 oz (28 g)
      Claimed low-temperature range: 15 deg. F (-9 deg. C)

      Tester Information

      Tester: Rick Dreher
      Email: redbike64(at)hotmail(dot)com
      Height: 6 ft (1.83 meters)
      Weight: 175 lb (79 kg, 12.5 stones)
      Age: 50
      Location: Northern California, USA
      Years backpacking experience: 37
      Backpacking skill level: Mid to advanced
      Backpacking style: Lightweight, mostly alpine (see bio at end of

      Report date: August 1, 2004


      "To sleep, perchance to dream; ay, there's the rub."

      Hamlet certainly had his reasons to not sleep well but dang it, when
      I've hiked my rear off for a long day on the trail I think I've
      earned the right to a good, long night's sleep. Instead, I
      frequently find myself waking several times during the night, often
      because of the hard, cold ground. To the backcountry we go with our
      pads and mattresses, promising ourselves that THIS TIME we're going
      to sleep the sleep of the angels.

      Sometimes we do, sometimes not.

      Our tired bods need respite from that stony ground. Our weapons
      include simple foam pads, clever self-inflating pads of foam encased
      in airtight fabric, and the good old air mattress. I love air
      mattresses for their comfort but discovered early in my camping and
      hiking career that unless they're paired with a foam pad they're
      strictly a warm-weather option—in merely cool weather they can
      freeze me solid. The air contained in the mattress's thick tubes
      conspires to rapidly suck away body heat on swirling convection
      currents and because the sleeping bag is flattened underneath me,
      it's helpless to stop this evil heat drain.

      Big Agnes had an idea: slap some manmade fiber insulation against
      the inside top of each tube and stop the heat vampires from their
      cruel deeds. Well, does it work?

      General Product Description

      Is it possible that this little black nylon stuffsack holds a full-
      length air mattress? Yup, it does. The Big Agnes REM Air Core Mummy
      Pad (BA Air Core) is fashioned of black 70D rip-stop nylon and folds
      small, small, small. Unfolding it there's little hint that this
      isn't a plain air mattress—where's the insulation? Folding the
      fabric over in different spots and rubbing it together tells the
      tale: there's a relatively thin layer of pile adhering to one side
      of the mattress on the inside, perhaps a quarter inch (6 mm) of the

      The "stuff" is Primaloft Sport, a synthetic insulation I've run into
      once before as the fill in the Integral Designs Mummer liner bag I
      tested for BGT. For decades, folks have been blowing loose down into
      air mattresses and inflating them with air pumps to achieve an
      insulated mattress while keeping the down dry and fluffed—such
      mattresses are available commercially today. Big Agnes has taken a
      different approach by placing a layer of synthetic fiberfill on the
      air mattress's sleeping side. The advantages of the synthetic
      approach over loose down are, in theory, that moisture from your
      breath won't rob the insulation of its ability to keep you warm
      (eliminating the need for an air pump) and the insulation shouldn't
      shift and redistribute itself, leaving cold spots. My soak-and-wring-
      dry experience with Primaloft Sport supports the notion that it can
      shed water; a few days in the hills should tell whether condensation
      from my breath inside the mattress has affected the pad's warmth.

      Field Report


      Success? Mostly.

      My first few nights with the BA Air Core showed mostly strengths and
      a few weaknesses. The pad is comfortable, sooo comfortable: back
      sleeping, side sleeping, stomach sleeping are all significantly more
      comfy than on any backpacking foam pad or self-inflating pad I've
      used. When it comes to protecting us from the ground, thickness
      rules the day and the BA Air Core's 2.5 in. (6.5 cm) of float trumps
      the competition. Warmth, however, has been a mixed bag--I've slept
      warmly on some nights and shivered on others.

      The Details

      I've taken the BA Air Core into California's Sierra Nevada in late
      spring and early summer for this test. All trips have been in fair
      weather, with clear skies and nighttime temperatures ranging from
      the high 30s to the mid-50s (3 to 14 C). Camp elevations have been
      between 8,000 and 9,500 ft (2,400 to 2,900 m). I've slept in a one-
      man single wall tent, under a tarp and in a bug bivy. My sleeping
      bags have been a Mont-Bell Alpine Down Hugger #5 and a Western
      Mountaineering Ultralight.

      As with any air mattress, the key to maximum comfort on the BA Air
      Core is correct inflation, which involves some tweaking. Inflating
      the pad takes me about a dozen breaths (take your time at altitude
      unless you relish becoming staggeringly dizzy). I like to do this
      right after getting into camp to allow the insulation time to
      decompress. As evening arrives and the ambient air temp drops, the
      mattress droops some so I must add more air. Ideally, I've added
      enough air that once I go to bed, all I have to do is release air
      stepwise until the pad is "just right." The valve opens and closes
      smoothly to aid this process but, If I let too much out, it's then a
      wrestling match to get the pad out from under me, add air then get
      it back underneath. If I'm in the bivy I have to actually evacuate
      to perform this feat.

      I use a clothes-filled cloth sack as a pillow, placing it between
      pad and sleeping bag hood. The sack can sometimes squirt out of
      place due to the slippery nylon used for both the pad and sleeping
      bag. The pillow will stay put underneath the pad but isn't as
      comfortable there. The pad's narrow foot end makes it fairly easy to
      slide my legs off, onto the ground. Fortunately I've not found
      myself doing this often enough that I'd prefer a larger, heavier
      rectangular pad. Finally, the Air Core will slide on a silnylon tent
      floor and it's important to pick a level tent site to keep this from
      becoming a problem.

      A sleeping system, pad/mattress included, is either warm enough or
      not. Especially for folks who've been shaving pack weight over time,
      we usually come to some point where we've gone too far and find
      ourselves shivering through an endless sleepless night. I may have
      hit this point the very first night I use the Air Core. In a
      relatively tiny backpack (2,400 ci/39 L) along with the pad I had
      the Mont-Bell sleeping bag and a bug bivy as my sleep system. The
      weather was nice enough that we chose not to pitch our tarp but even
      though the night was still, it got so cold that I put on pretty much
      all my clothing during the night and still slept little. The morning
      temp was under 40 F (3 C). Standard disclaimers about my metabolism
      on that day apply: it's possible that somebody else using the same
      equipment in the same conditions would have been fine, but I was
      not. What I also cannot say is how much of my chilled state was from
      the sleeping bag (which, like the pad is rated for these temps) and
      how much was contributed by the pad. I did seem to be colder
      underneath than on top.

      Other nights in other campsites I've used my WM bag which is
      considerably thicker than the Mont-Bell, and slept in a Tarptent or
      under a flat tarp. Temps stayed in the 40s and 50s (7 to 14 C) and I
      slept warm and well. I've not given up on the BA-MB combination
      because their combined bulk and weight are impressively small. But I
      suspect I have to limit their use to mid-season trips unless I
      perhaps combine the pair with a really warm garment, such as a fat
      down vest or jacket.

      Design, Materials and Construction

      As already noted, the BA Air Core is an air mattress fashioned from
      coated, somewhat slippery rip-stop nylon fabric. The mattress has
      eight tubes running lengthwise; the between-tube seams have inner
      fabric baffles, i.e., they aren't welded through directly to the
      other side. This test mummy-shaped Air Core (rectangular ones are
      also available) can be described as coffin-shaped, with the head and
      lower leg areas lopped off at angles to reduce size and weight. The
      plastic inflation valve is at the head end, to the sleeper's right.
      It's placed conveniently to allow air to be released to adjust
      comfort without getting out of bed. The label side is the sleeping
      side—where the insulation is.

      On first unrolling it's difficult to find tactile evidence of any
      insulation in the Air Core, but after several minutes inflated, a
      pinch test of both mattress sides reveals the insulation's presence
      on top. I initially didn't think It would be possible to figure out
      what's going on inside without dissection, but then discovered that
      by holding the Air Core to the sun I can see strips of Primaloft
      batting in each tube. They appear to be held in place by the baffle-
      to top surface seam on one side only. I'll guess that each batting
      strip is about a quarter-inch (6 mm) thick.

      The test pad is a surprising 1.4 oz (40 g) lighter than the Big
      Agnes specification.

      A note on the Big Agnes bag and pad system: This and other BA mummy
      shaped pads will fit inside BA sleeping bags. To save weight, bulk
      and cost, BA bags dispense with insulation underneath, instead
      providing a fabric pad sleeve. In that role the test Air Core pad
      should fit inside a BA sleeping bag like a glove, but I regret to
      say I don't have a BA bag with which to test the system. That Horse
      Thief bag sure looks interesting, too.

      Wear and Tear

      The BA Air Core's coated rip-stop exterior shows some minor scrapes.
      Dirt clings to the black fabric but wipes off easily. Inflation
      tests at home show the mattress slowly loses air overnight, implying
      a very slow leak, but dunk tests don't reveal where. Without
      evidence of a fabric pinhole or failing seam I have to suspect the

      Visual inspection holding the inflated pad up to the sun reveals a
      problem: three of the batting strips have come loose several inches
      at the pad's head end, and now flop around inside their respective
      inflated tubes. I have no way of knowing whether this is a
      production problem or one that's developed with use. I've learned to
      shake the mattress, head end down, to coax them back in place before
      setting it on the ground in hopes that they'll stay put during the
      night. I can't tell whether they cling to the tube tops or not; if
      not, they won't provide any warmth in those areas.


      The Big Agnes Insulated Air Core mattress fulfills most of its
      considerable promise of making backcountry sleep a very pleasurable
      experience. The comfort is undeniable, but I remain skeptical that
      it's truly warm down to the temperatures Bag Agnes claims for it (to
      15 deg [-9 C]). My early test with a very light bag on a night much
      warmer than that leaves my original doubts in place.

      Compared to my Therm-a-Rest backpacking pads and plain foam pads,
      the BA Air Core is much more comfortable while taking up less pack
      space. It's lighter than the T-Rests, heavier than the foam pads.
      Without experiencing a single chilly night dedicated to trying each
      in turn—an experiment I'm unlikely to orchestrate—it's not possible
      to reliably rank them for warmth. The crux of the temperature
      question is whether using the Air Core necessitates taking a
      heavier, bulkier sleeping bag than I would have otherwise, negating
      the pads obvious weight and bulk advantages over the options.

      Despite my remaining reservations about warmth, considering its
      demonstrated comfort, ease of use, relative light weight and very
      compact packed form, the BA Air Core should get serious
      consideration for space in your gear closet and on the trail.

      Long-Term Test Questions

      * Will the BA Air Core mattress be reliably warm for me into the
      fall season? Could a small, thin torso-length foam pad (such as
      those used in some backpacks) extend its cold-weather range?

      * Will the mattress continue to resist punctures, cuts and abrasion,
      and will the overnight air loss get any worse?

      * Will the remaining insulation stay in place or will it continue to
      pull away from the seams?

      Brief Backpacking Bio and Cold, Hard Ground Experience

      When I first joined the Boy Scouts they neglected to tell me that
      some kind of mattress would be nice underneath my kapok sleeping
      bag. A couple of trips sleeping on the ground wearing every stitch
      of clothing--and my boots--convinced me to look around and see what
      the comfortable kids were sleeping on. A-ha, air mattresses!

      So I got one. And still I froze, but the hard ground was far, far
      away, a definite improvement. I later learned the newspaper
      insulation trick and was a happy sleeper the rest of my Scouting
      career (in kapok), as long as we weren't backpacking.

      Backpacking first had me carrying an air mattress, then a mattress
      and ensolite foam pad, then just the pad (with some stops along the
      way for testing bubble wrap, space blankets and the like). The
      wooded Cascades and Olympics usually provided sleeping spots soft
      enough that an insulating pad was fine, plus I was a lot more…
      pliable than. The Therm-a-Rest came along after I'd switched to
      California's Sierra Nevada where the elevations are manly and the
      rocks are too, and rocks are what I normally sleep on. Never mind
      the weight and bulk, the T-rest had me sleeping again. But never
      like those early days in the Northwest.

      I learned camping and hiking in Boy Scouts, tramping the Washington
      Cascade foothills (lugging canvas pup tents, Trapper Nelson and BSA
      aluminum-canvas backpacks, kapok sleeping bags and always an axe).
      From these beginnings I eventually learned backpacking as a singular
      pursuit and found a home away from home in the Cascades and
      Olympics. Now living in northern California, most of my hiking is in
      the Sierra Nevada with trips ranging from overnight to weeklong
      excursions. I occasionally hike in the coastal ranges as well. I've
      been fairly successful shedding pounds and ounces from my pack the
      last three or four years. I've been doing this for several reasons:
      traveling easier and farther, freeing myself from as many trappings
      as I'm comfortable discarding, and extending the duration of my
      backpacking career. My total pack weight for three-day summer
      excursions, including food and water, is now roughly 25 pounds (12.5
      kg), and a recent eight-day trip starting weight was a bit over 30
      (14 kg).

      My thanks to Big Agnes and BackpackGearTest for the opportunity to
      participate in the insulated Air Core Mummy Pad field test.

      RTD 8.1.2004