Big Agnes Insulated Air Core Inflatable Sleeping Pad
Initial Report

Product Information

Name: Big Agnes Insulated Air Core Inflatable Sleeping Pad
Model: 20x72x2.5 mummy pad
Maker: Big Agnes Inc.
http://www.bigagnes.com
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
Male
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
Style of backpacking: Lightweight (see bio at end of report)

Report date: June 10, 2004

Introduction

“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?

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 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 (7 mm) of the stuff.

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—these days such mattresses are available commercially. Big Agnes has taken a different approach by laminating a layer of synthetic fiberfill to the air mattress’s sleeping side. The advantages of this approach over 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 can’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.

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 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 presence of the laminated insulation on top. It’s not possible, of course, to know exactly what’s going on inside without dissection, but a fair guess is that there’s about a quarter-inch (7 mm) of insulation backing the top fabric skin.

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.

In the Urban Bedroom

Remove from stuffsack, unroll, inflate, lie down, use valve to adjust air for maximum comfort. At the casa this routine takes perhaps three minutes with the BA Air Core. The plastic valve allows good airflow and closes easily when there’s enough inflation—won’t freeze my lips in cold weather either. I over-inflate the mattress beyond what I know I’ll need so that when I lie down so all I have to do is bleed off excess air until the fill is perfect. It’s not really possible to add air to an air mattress while lying on it.

The BA Air Core is as comfortable as I’d expected, even with a few small, kid toys tossed underneath as faux pinecones. The foot area is narrow, and is easy to slide off of when shifting about. Because I’m generally a side-sleeper, I’ll expect to find at times that my lower legs have slid off the pad. Because I’m used to sleeping on a ¾ length pad with my lower legs off the end, I’m not expecting this to be much of a problem, but on cold nights I’ll probably make a point of keeping some extra clothing down at the foot end. Sleeping bag fabric does slide easily on the BA’s nylon shell. Hopefully that won’t become a problem in the field. I’ll also be interested to see whether the mattress sticks or slides atop a silnylon tent floor.

Field Test Questions

* Job number one: is the BA Air Core mattress comfortable and warm?

* Do the mattress’s narrow width and taper make it difficult to stay atop?

* Is the mattress too slippery? Will my sleeping bag slide off or will it slide on a tent floor?

* Is the mattress rugged enough to resist punctures, cuts and abrasion?

* Does the insulation really stay in place and prevent cold spots?

* Will the BA Air Core help me continue to cut my pack weight and bulk?

* How does the BA Air Core compare to my Standard and ProLite Therm-a-Rests in comfort, weight, pack bulk and durability?

Conclusions

The Big Agnes Insulated Air Core mattress holds considerable promise for making backcountry sleep a very pleasurable experience. They don’t have to sell me on the comfort of air mattresses, but my skeptical side wonders how well a thin layer of insulation will fare in keeping the cold ground at bay? BA claims the insulated Air Core is good down to 15 deg f (-9 deg C) and I wonder about this claim, because never in my hiking days have I been warm at those temperatures with such a thin insulation layer underneath me.

Rhetorical question du jour: Big Agnes describes the insulated Air Core as a three-season mattresses, noting it’s “Designed to quiet those seeking an air pad suitable for use in lower temperatures.” If this is the case, does that make the un-insulated version, a two-season mattress? One-season?

The hangtags give a bit of sales information but are mute on how to use and care for the BA Air Core mattress. They don’t tell you which side of the mattress to sleep on, much less how to use the repair kit. However, if you speak Italian and want an accounting of Primaloft’s benefits, you’re in luck.

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

Field Test Plan

I'll carry the BA Air Core on backpacking trips when I'm planning to sleep on the ground (it's too narrow to use in a hammock and besides, there's no need for an air mattress’ cushy comfort of in a hammock when all one needs is a wide, simple insulating foam pad). I expect my hikes during this test will be in the Sierra Nevada, where the pad will serve against an array of surfaces, from loose soil to broken rock. The test period will run through fall, so I should experience a range of nighttime temperature from mild to well below freezing. Rain and snow are completely optional.

The BA Air Core has less packed volume than any pad I've used, and its weight is mid-point between my foam hammock pad and my Standard T-rest. I'll be interested to see whether it gives me the opportunity to shrink my overnight pack further than I have before. My shelter options include a Tarptent Virga, a Golite Hex, a simple tarp and sleeping in the open. I may also call upon my Outdoor Research Bug Bivy and there's always the possibility of an actual tent.

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 06.11.04