GEAR REVIEW: Big Agnes Insulated AXL Air Sleeping Pad and Pumphouse Ultra Sleeping Pad Inflation Pump

By Will Rietveld

Definitely for lightweight backpackers, and even for ultralighters, a comfy sleeping pad is a comfort item to spend a few ounces on in order to get a good night’s sleep.

The specs for the new Big Agnes AXL pad, coming out spring 2018, sound really good – weight as little as 9.6 ounces for a full-length, mummy-shape, 3.25-inch thick (that’s correct) inflatable sleeping pad. That’s down right plush!

The lightest of their AXL family of pads is the uninsulated mummy version, measuring 20x72 inches and weighing 9.6 ounces. That’s the one I tried to get for testing, but it wasn’t available, so I settled for the insulated rectangular version (shown) weighing 11.9 ounces.

What is remarkable about this pad, compared to the competition, is its thickness and lightweight. It’s lighter than the full-length Therm-a-Rest Neo-Air XLite pad and much thicker.

So, given all these good numbers, how does the AXL pad perform for lightweight backpacking?

Specifications and Features – Sleeping Pad

Manufacturer	Big Agnes (www.bigagnes.com)
Product	Insulated AXL Air Sleeping Pad (rectangular insulated version tested)
Materials	“lightweight double-ripstop nylon with aviation grade TPU lamination”, Primaloft Silver insulation with reflective film
Dimensions	20x72x3.25 inches; outer tubes are 3.75 inches
Weight	Mfr specification 11.9 ounces, measured weight 12.4 ounces (pad only)
Features	Single 2-way valve, interior antimicrobial treatment, quick deflation valve, micro-release button for inflation adjustment, larger outer chambers to cradle sleeper
Sizes Available	Regular, wide, and mummy; insulated and uninsulated
Included	Pad, stuff sack, repair kit
MSRP	$180

Specifications and Features – Inflation Pump

Product	Pumphouse Ultra Sleeping Pad Inflation Pump
Materials	Ripstop nylon
Dimensions	19.5x13.5x8 inches
Weight	Mfr specification 2.9 oz, measured weight 2.55 ounces
MSRP	$35

Description

The AXL inflatable sleeping pad is available in Regular (20x72 inches), wide (25x72 inches), and Mummy (20x72 rounded and tapered ends). Shorter lengths are not available, and would not work well because of the pad’s thickness.

Insulation is Primaloft Silver synthetic, plus a reflective film. Big Agnes prefers to provide a temperature rating (15F), rather than play the R-rating game. Remember that number. The uninsulated pads are grey and the insulated pads are red.

The Pumphouse Ultra Inflation Pump is a pump bag with a fitting that pops into the inflation valve on the sleeping pad. It’s claimed to fit other Big Agnes pads as well as traditional valves. It works as follows: attach the outlet to the pad’s valve, open the sack so it fills with air, fold the top over, and roll the bag toward the pad.

Field Testing

I tested the AXL pad on spring backpacking trips in southern Utah and summer backpacking trips in the southern Colorado Mountains. Nighttime temperatures were as low as 27F.

 

Inflating the pad by mouth requires about 30 deep breaths, which is quite a bit of effort. Using the Pumphouse inflation bag is much faster and easier, and it doesn’t introduce moisture into the pad. I found the pump bag easy to use, and it gets easier as you learn the technique. I tested the Pumphouse bag on a conventional inflation valve and did not find it to work as Big Agnes claims. The pump bag effectively doubles as a stuff sack, but I don’t see how it can be used for a portable shower as claimed.

I like its large, one-way inflation valve because air does not leak out between blows. The micro-release button is inside the cap of the valve; after the pad is inflated, simply press on the flap and release a little air to get the desired firmness.

The AXL pad is quite durable, so this is not an ultralight pad that will require frequent patching. And Big Agnes provides a patching kit just in case.

The plus side of the AXL pad is its amazing comfort. I never expected to put the words “3.25 inches thick”, “comfortable, and “lightweight” in the same sentence but Big Agnes pulls it off. This pad is like floating on a cloud; made in heaven for lightweight backpacking, and some ultralighters may adopt it too.

The minus side was a big surprise to me – even though the pad I tested is insulated, I found the pad to be cold at temperatures below 40F. Specifically, my bottomside got chilly, enough to inhibit sleep. My observed threshold of around 40F is a big difference from the claimed 15F comfort rating.

 I verified that the chill problem was indeed the pad by placing a blanket over the pad and sleeping on that combination on a similar sub 40F night; I had no problem staying warm in the same bag, clothing, and shelter.

 

Note that that my observed 40F comfort threshold is for me; other sleepers may experience discomfort at cooler or higher temperatures, and hotblooded sleepers may not experience any discomfort at all.

To investigate the issue, I peered into the inflation valve opening to see what’s inside, and couldn’t see any insulation. Next I held the pad in front of a strong desk light and found that the pad is insulated with a thin sheet of synthetic insulation bonded to the upper pad fabric, and the insulation sheet has large oval holes (2x3 inches) in it so it doesn’t interfere with top/bottom fabric welds that determine the pad’s thickness and texture. Note in the photo below that the insulation has some rather large thermal leaks in it.

This photo of the pad with backlighting shows a thin insulation sheet inside bonded to its upper surface. The insulation has large oval cutouts to allow room for top/bottom fabric welds to create the pad’s thickness and texture. The inflation valve is at the upper left.

 

My conclusion is the AXL pad’s insulation is insufficient to meet its claimed comfort rating, for me at least. It’s thin with large holes in it, and is not very effective.

Assessment

By my testing, I found the AXL pad to be a mixed bag. On the one hand it’s very comfortable. However, it’s overweight by a half ounce, and its warmth (for me) is nowhere near the claimed 15F. The problem was consistent; whenever the nighttime temperature dropped below 40F I got chilly on my bottomside. Note that the insulation in a sleeping pad works in much the same way as an insulated jacket; rather than feeling a cold line where the jacket is stitched or the pad insulation has a cutout, you feel an overall warmth or coolth. More thermal leakage means less warmth. In the case of the AXL pad, the uninsulated area due to incomplete coverage of the pad's topside plus numerous large cutouts allows a lot of thermal leakage, so more coolth. 

Because of this shortcoming, I consider the AXL Air pad, in spite of its insulation, to be a summer only pad when used by itself.

One solution to make the AXL pad warmer is to carry a thin foam pad to place over it to provide extra insulation when it’s needed. The one-eighth inch thick Gossamer Gear ThinLight pad (2.4 ounces/$18) is a good choice. It’s full-length, stays in place over an inflatable pad, and has numerous other uses. I have tested the ThinLight to extend the warmth of other sleeping pads, and found it adds a remarkable amount of extra warmth for its minimal weight.

However, when you add up the actual weight of the AXL pad, the Pumphouse inflation bag, and a supplementary ThinLight pad you arrive at 17.4 ounces, which substantially reduces the lightweight appeal of the AXL pad.

One consideration for campers who use a shelter with limited headroom is the thick AXL pad will reduce headroom even more. In other words, the AXL pad works best in a tent with plenty of headroom.

In my opinion, the AXL pad is too heavy for ultralight backpacking, so I will reserve it for lightweight backpacking, base camping, and car camping. Lightweight backpackers will love it for its exceptional comfort and reasonable weight. And there should be no problem with late night chills on warm summer nights.

I would appreciate reader comments on their experiences with this pad. Does your bottomside get chilly late at night when the temperature hits its low? And about what temperature does that occur? Or perhaps you don’t find any issues at all. Share your experience below.