Therm-a-Rest NeoAir XTherm NXT sleeping pad: Tested

By Mark Watson 15 September 2023
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Ultra-light, and ultra-warm, is the NeoAir Therm NXT the best four-season sleeping mat? We doss down in the depths of winter to find out.

Along with a toasty sleeping bag, a quality sleeping pad is the make or break of a good night’s sleep, or even an entire trip, when venturing off the beaten path via human powered means. So, when winter comes knocking and the alpine regions call, super-light but toasty-warm sleeping pads are the name of the game, but in this category, ‘messing up’ means ‘miserable’. In fact, when it comes to camping above the snow line, choosing to spend your hard-earned dollars on a high R-value (thermal resistance rating; the higher, the more warmth provided) sleeping pad might just be some of the best dollars you will spend and at the pointy end of this category is the Therm-a-Rest NeoAir XTherm NXT. 

NeoAir XTherm pads are highly revered in the realms of four-season camping, for good reason, and as Aus Geo Adventure’s resident winter-wanderer, and cold sleeper, I offered myself up both last year and this year as crash-test-snow-dummy to separate the good from the bad. Or, in this case, the cold from the warm, aboard the latest and greatest in sleeping pad design. I took to the hills, beaches, rivers, and ravines and lay down on everything from sand and snow to rock and ice in a bid to determine whether this highly acclaimed sleeping pad really lived up to all the hype. Spoiler alert: It did.


In short, the Therm-a-Rest NeoAir XTherm NXT is a lightweight super-warm four-season sleeping pad designed for extreme cold and alpine conditions. It is designed with horizontal baffles, a multi chambered core, high tech materials and a WingLock valve, all combining to deliver a 439 gram (regular size) sleeping pad with a rather mind-blowing 7.3 R-value. The former Therm-a-Rest NeoAir XTherm NXT was no slouch either, with an R-Value of 6.9 at 430g.

The pad achieves such warmth for weight by replacing the insulating ‘fill’ many manufacturers use, with the super nifty technology of ThermaCapture and Triangular Core Matrix. ThermaCapture is a super thin, featherweight reflective film designed to reflect radiant heat back to your body and is used extensively throughout the internal structure of the Therm-a-Rest NeoAir XTherm NXT. Triangular Core Matrix is a cleverly designed dual layer of triangular baffles developed to limit free flow of air within the pad, thus limiting convective heat loss and separating the cooler ‘base’ air from the warmer ‘radiant’ heat above. 

A hard-wearing 70-denier (D) nylon base offers protection against the wear and tear of extended expedition use whilst a 30D ripstop nylon top fabric sheds weight to keep the pad super light and packable. The WingLock Valve offers super-fast inflation via the pump-sack, the ability to micro-adjust pad firmness, even as you lay on it, and rapid deflation. The mummy shaped sleeping pad ups its thickness from last year’s 6.4cm Xtherm to 7.3cm for the XTherm NXT. The new model is optioned in three sizes: regular (51cm x 183cm, 440g), regular wide (63cm x 183cm, 540g) and large (63cm x 196cm, 570g).

In the field

I freely admit I may have had previous love affairs with Sea to Summit’s Ether Light XT (love the valve and pillow-lock) and Exped’s Downmat (sooooo warm and cushy), however the Therm-a-Rest NeoAir XTherm NXT has won me over to become my new favourite for cold weather wanderings.

Field testing last season’s Therm-a-Rest NeoAir XTherm quickly proved ThermaCapture and Triangular Core Matrix are not just marketing hype but in fact deliver exceptional warmth for weight. At 440g the regular size pad is as light as some three-season sleeping pads, and whilst our large pad is 130g heavier than the regular, it is well worth it for cosy toes, even on a frozen ground.

Those horizontal baffles, combined with the 7.6cm thickness, aid overall comfort on more rugged surfaces.

A mid-winter split boarding mission to the South Ramshead Range saw the pad perform exceptionally well, however the mercury never really dropped to bone-chilling temperatures and so it wasn’t until I camped high above a frozen Lake Albina, with temperatures dropping to double digit negatives, that the pad really proved its mettle. In a minus eight degree Celsius (comfort rating) sleeping bag, the NeoAir XTherm was the only barrier between my sleeping bag and a frozen single-skin tent floor, and I managed to stay reasonably warm (I did get a cold nose). My XTherm adventures continued through mountaineering courses and historic-hut-adventures in the Victorian Alps, then atop a frozen Mt Bogong and even into the Pilot wilderness before finally revisiting the NSW main range again. All throughout the trial period the sleeping pad excelled and remained warm, even when damp, and importantly puncture-free thanks to that 70D base finding the right balance between weight-shaving and durability.

Related: Camp sleep systems: Top tips for a perfect night in the outdoors

The new 7.6cm thick pad is 1.2cm thicker than its predecessor, and whilst not the thickest mattress on the market its horizontal baffles work a treat, delivering a sturdy base for a comfortable night’s sleep, whether it be on rock, grass, snow or ice. ThermaCapture and Triangular Core Matrix perform better than many thicker mattresses, even some insulated ones, for retaining heat and delivering a warm, dry bed. On a number of backcountry explorations I afforded myself the luxury of a closed cell Therm-a-Rest Z-Mat as a base pad and suggest the duo might just be the warmest and most comfortable lightweight alpine bed setup I’ve ever used. 

The WingLock Valve is a vast improvement over the old valve system and now performs three times faster via the supplied pump-sack, but just as importantly the WingLock offers user-friendly fine-tuning (even whilst wearing gloves) along with rapid deflation, and thus delivers the final piece of the jigsaw for a great all round sleeping pad.

The final word on the Therm-a-Rest NeoAir XTherm NXT

There is no doubt that hardcore adventurers, especially in Australian conditions, can suffer with super-light three-season kit (yes, that’s you, Huw Kingston) but for the cold sleepers amongst us (like me) the four-season Therm-a-Rest NeoAir XTherm NXT is the epitome of the ultra-light, ultra-warm sleeping pad. Whilst it’s not a cheap offering, Therm-a-Rest has delivered what might be considered one of the best – if not the best – lightweight four-season sleeping pad presently available. Plus, it is lightweight enough to nearly do all-season duties. If you’re willing to cough up a few extra dollars to keep those toes toasty, then the Therm-a-Rest NeoAir XTherm NXT might just be the pick of the bunch. 

RRP: $575 See Therm-a-Rest for more info, stockists and the brand’s full range of sleeping pads.