RRP: £150 (Regular size, original shape) £170 (2015 Max version, Regular size)
Weight: 430g (Regular size, original shape) 490g (2015 Max version, Regular size)
Thermal R rating: 5.7
After a few years of broken sleep on mediocre mats. Press coverage of the Neoair xTherm had tempted me to take a chance on Thermarest’s new winter lightweight mat. Both Oisin and I have been using xTherm mats for over a year, while John has recently purchased the newly released Max edition. Read on to see our thoughts on this mat after over 25 nights of wild camping in a range of conditions.
Overview
The Neoair range has moved away from the usual foam-filled, self inflating approach to insulation, abandoning foam altogether. This brings the advantage of the xTherm being much more packable than a foam filled mat, with the regular size packing down to slightly larger than a 1 litre wide mouth water bottle. The max version is slightly larger, but is still quite close to the size of the 1 litre bottle:
The regular shape of the xTherm is tapered at the top to reduce bulk, while the max version (new for 2015) has a square cut for those who like a little extra room.
Rather than using foam for insulation, the xTherm uses a series of internal triangular foil baffles, mirrored against one another at both the bottom and the top of the mat. The triangular baffles trap heat while the reflective foil material reflects heat back towards the user’s body, increasing the warmth with little additional weight penalty. This is how the xTherm manages to be both light and packable, while still warmer than any foam mat I have ever used.
The advantage to using a thermacapture metallic matrix rather than foam is that the mat is much more hollow when deflated, leading to a smaller size and lighter weight. Unfortunately this also means that the mat is not self inflating (while a battery powered pump accessory is available) It will also take quite a lot more puff to inflate this mattress than other foam based mats.
When fully inflated the mat goes from being just over a millimetre thick to 6.3cm thick. This provides quite a lot of lift off the ground, increasing the comfort and warmth of the mat.
The mat uses the usual twist and pull style Thermarest valve. While the valve in the regular cut protrudes backward from the wide profile of the mat, the valve in the Max edition protrudes upward from the top of the mat. The valve does not push into the mattress itself and remains protruded. Given the generous sizing of the max cut this shouldn’t be a problem for most users.
Thoughts from the trail
The first thing which strikes you about this mat is the high level of insulation it provides. Having never used a mat with reflective technology before, the sensation of such high heat retention was quite unusual. In warmer weather I’ve been able to downsize my sleeping bag, or in some milder wearer wear insulated trousers and a down jacket instead. The mat punches well above its weight in terms of heat retention and is my go-to choice for colder trips, but I’ve never found the warmth to be a problem in warmer weather. Rather than bring a heavier, colder mat, I simply reduce the amount of insulation I sleep in, with a lighter bag, or less layers.
The regular cut of the xTherm is very bivvy bag friendly. I have used it inside a Terra Nova Titan bivvy bag almost exclusively in 2014/2015 so far and it fills the inside of the bag without distorting its shape. This leads to a very comfortable night’s sleep as there’s very little uncovered space inside the bivvy. This is to say nothing of the extra rest gained from knowing your expensive sleeping mat isn’t going to blow off into the distance should you roll over too far in the middle of the night.
Due to its size and shape, I could not recommend the max version for those who use a bivvy bag as their primary form of shelter. The mat will not fit inside any bivvy bag I have seen, and due to its lightweight nature and high profile – it will blow away easily if not tethered down by a bungee cord or similar.
The xtherm inflates to a high level of thickness, which I have found to greatly improve the comfort of a night’s sleep, even when camping on uneven ground.
Due to the relatively hollow innards of the mat, it does have a tendency to collapse slightly at the edges when bearing weight in those areas. Given that the sizing of the regular mat works well for me I’ve never found this to be an issue. If you suspect you may need a little extra width, consider the large size or max version of the mat for additional width.
The foil fabric does make a slight crinkling sound during movement, but given the myriad sounds to be experienced in the outdoors, this is unlikely to be a major issue for most campers. I rarely notice the crinkling, it being on par with the sound of my sleeping bag rubbing against the fabric of my bivvy bag or tent.
The small packed size makes the xtherm extremely packable. It can be stored inside your rucksack rather than strapped to the outside and allows for quite a lot more room when packing for a trip. It also rolls up easily and there is plenty of extra space inside the storage sack – so you won’t struggle to pack it away during that morning deluge the next day.
I have found it quite manageable to include an xtherm, reactor stove, 600g down sleeping bag and titan bivvy in a 32 litre pack, alongside the usual essentials like food and a head torch. If you’re looking for something warm, light and packable for multi day trips, the xtherm won’t disappoint.
Regarding durability, neither Oisin nor I have suffered any mishaps or punctures in just over a year of use so far. The mat comes with a puncture kit included and a lifetime guarantee. I frequently stand on the mat or climb up onto my knees when getting in and out of my bivvy bag and this has never caused any issues.
This mat ticks all the boxes and has the potential to truly change your camping experience, particularly for multi day trips where weight is a concern. The neoair xTherm comes with Hikersblog’s highest recommendation.
Two Year Update – August 2016
It’s now been two years since Oisin and I first started using the xTherm. We’ve had another year of hiking and camping, taking the xTherm on another 15 hiking trips since this review was written.
The mat continues to perform well, keeping us warm in winter and allowing us to make do with a lighter sleeping bag in summer. I’m still very pleased with this mat’s performance, weight and pack size and I have had no reason to look for different mat for my sleep system.
Eleven Year Update – October 2025
As of October 2025, Ed and Oisin are still both using their xtherm mats regularly. Neither mat has developed any issues and they continue to perform well.
Therm-a-Rest have released a new NXT version of the mat, which we will review for 2025.
Video Review
Check out our video overview of the neoair xTherm and xTherm max:
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Regular: Max:
In the video is that the xtherm max regular or large? You said 200g heavier which would be the large. The max regular is only 60g heavier.
Thanks!
Hi Sean,
The max is a large. It’s almost comically big, I’d honestly say unless someone was over 6ft it isn’t worth the weight difference to go up in the size bands.
[…] jacket. It compresses down extremely small and provides more than enough warmth. Combined with the xtherm mat I had a nice combination of lightweight, packable and toasty warm. When you spend worknights in the […]
[…] dry, and packs down well and weighs less than even a lightweight tent. Combined with the xtherm mattress (reviewed here) and a good down sleeping bag, it’s a warm, lightweight and packable sleep system which is […]
Hey. I´m 6 feet tall, and unsure if I should get the Xtherm Large or Large MAX. My issue with the regular Xtherm and regular Xtherm MAX is the width, and for wintertime the length also. Any thoughts on which to choose?
Hi David, I would go with the large, rather than the Max. Oisin is just over 6ft and uses the regular size and shape with no issues, although his feet do hang off the end from the ankle down. The large size / regular shape will be fine. Large Max is almost comically large and will limit your choices of tent (and rules out bivi entirely)
[…] Full review here: Therm-a-Rest NeoAir xTherm […]