The ideal camping mat for me would offer the comfort of an air bed coupled with the low weight and small bulk of a foam mat. Well, it seems that, with the new versions of the NeoAir range, Therm-a Rest have hit the nail on the head.
The NeoAir XTherm marks a step change in the world of four-season backpacking sleeping mats – it weighs a mere 430g (Regular), is 6.3 cm thick, provides a R-value of 5.7 and packs down to the size of a Nalgene. To put that in perspective, a Prolite Plus, what could be considered the benchmark of the Therm-a-rest range, weighs 620g, is 3.8 cm thick and has a R-value of 3.8. The XTherm achieves such warmth for low weight and bulk through the use of patent-pending technology that was developed over seven years. The horizontal baffles are made up of what Therm-a-Rest are calling the Triangular Core Matrix, which are interlocking triangles.
These triangles trap warm air and improve the stability of the mattress. Between the upper and lower layers of these baffles are four layers of Reflective Barrier (also patent-pending). These layers reduce the convective heat loss to the ground by recycling body heat in the upper layer of baffles and improve the efficiency of the Triangular Core Matrix. Not being foam, the materials inside the mat are also not going to absorb moisture and degrade. The mat is, however, rather noisy compared to a foam one, sounding like a large crisp packet. This is at first quite noticeable when moving around, but soon only my tent partner was aware of the crinkling!
The bag supplied doubles as a pump for use when you're short of breath, but I found it to be relatively ineffective and even at over 6000m I was able to muster enough from my lungs to inflate the mat to a reasonable firmness. Another notable positive was how few breaths the mat required to be fully inflated – my tent partner had a Prolite and spent considerably more time and red-faced effort getting it to an acceptable state.
"These reflective layers reduce convective heat loss to the ground by recycling body heat in the upper layer of baffles..."
"The mat is, however, rather noisy compared to a foam one, sounding like a large crisp packet..."
Despite its thickness, which I initially presumed would make the mat quite unstable, I experienced no rocking and rolling or bouncing when shifting around. Admittedly the noise produced during this squirming does make the mat sound a lot less sturdy than it really is. The build quality of the mattress is the excellent that one expects from Therm-a-Rest, but if you are unlucky enough to pick up a puncture, make sure the included repair kit is close to hand: unlike a self-inflating foam mat, if the XTherm deflates there's nothing at all to insulate from the ground.
In summary, the outstanding warmth to weight ratio achieved with this mattress should make it contender for anyone's next trip. It is aimed at winter use, but as it weighs less than any of the self-inflating mats Therm-a-Rest manufacture, I would consider it for any excursion, including the coldest of snowy camps. Coming in at £150 RRP for a regular length, the XTherm is probably too far over the £100 mark for most of us. One has to consider if spending £40 extra than a Prolite Plus for a saving of just under 200 g is worth it. It is, however, a great deal warmer than any self-inflating mat I've used, and if low bulk and light weight are key drivers and the frequency of use is high enough, then it's definitely worth treating yourself.