I didn’t plan on spending this amount on a sleeping mat BUT the Thermarest Neoair Xtherm ended up being the best mattress I’ve had. It’s a chunk of money but for the ultralight weight and thermal qualities, it is definitely the best in it’s class as far as I can see. Find out why.

Thermarest Neoair Xtherm Mattress

When you venture out into the snow, and then altitude, to wild camp you really need to be off the ground. The 2.5 inch Thermarest XTherm mattress does just that. This is really comfortable whether you sleep on your back or on your side, and I’m so much warmer than before.

There’s plenty of space on it and I don’t find myself falling off. Or worse, having my side or a knee touching the cold ground. You’ll find this infuriating in cold conditions with smaller mats.


The mattress and the pump bag fits into a stuff sack. Rolled up, nice and neat, it’s then 330mm x 100 diametre.

I do find it a bit big whilst blowing it up. Gets in the way a bit. So, you do have to work a way out to get this done inside your shelter for when it’s raining. Rolling it up neatly next morning is as much of a pain as any other mattress. Some people talk about squeaking noises. Maybe they’ve gotten rid of that in the newer models because I’ve certainly not experienced it.

Thermarest Neoair Xtherm mattress with pump
Thermarest Neoair Xtherm mattress with pump

I really appreciate the bag pump instead of blowing moist air into it! If you don’t mind a little bit more weight and the sound they also do a battery operated pump.

What is the R-Value?

If we compare the ‘Resistance’ to heat flow of the Xtherm with a couple of other Thermarest mattresses, we quickly see why it’s rated as a four season mattress.

Mattress (all regular size for comparison)R-valueWeightPrice
Neoair UberLite2.3250g£207
Neoair XLite4.2340g£144
Neoair XTherm6.9430g£188
These values were taken from the Therm-a-rest website in 2020

Unlike the U-value, which measures a material’s thermal conductivity, the R-value tells us exactly the resistance of the product. It takes the mattress thickness into consideration.

To put this in the real world, a mattress with an R-value of 1 to 2 is ok for summer. However, when you’re sleeping on snow or wet, frozen ground, you really need resistance in that mattress to take away your the heat from your body. This list from Therm-a-Rest shows you how the R-value relates to the camping season.

  • Summer (1-2 R-Value)
  • 3 Season (2-4 R-Value)
  • Year-Round (4-6 R-Value)
  • Extreme Cold (6+ R-Value)

More details can be found on the Therm-a-Rest website here.

Ultralight in the UK

Of course, the XTherm is the heaviest of the mattresses in the study. However, it’s still incredibly light compared to the ProLite I was using a couple of years ago at 500g. Hikers in one of my ‘ultralight’ groups talk about their pack being below 5kg. But remember these people live in warmer climates (where I’ve used a piece of bubblewrap for a mattress without getting cold!).

In the UK and Northern Europe, we need a mattress that protects us more from the cold. In the ultralight backpacking arena, the XTherm, although it’s not the lightest of the dozen or so mattresses I’ve used over the years, really does the job very well and it is my ‘go to’ mattress.

The £188 price tag is the best I’ve found the the Thermarest Neoair Xtherm mattress. It can be bought on this link.

Winter wild camping
Winter wild camping

Sleeping Warm – Wild Camping

Choosing the right mat is essential for keeping warm when you’re wild camping but there are many things you can do to make sure you have a comfortable and warm night’s sleep. Take a look at this…

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2 thoughts on “Thermarest Neoair Xtherm Mattress”

  1. A good post. I used Exped SynMat 7DLX for several years until I focused on light weight over pack size and went with an Alpkit cloud base mat; basically a lilo. Fine for summer but definitely felt the chill in the shoulder months. I’m impressed by the weight of the mat you reviewed, the Exped mat always felt heavy and bulky to pack on the bike.


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