Nemo Tensor Extreme Conditions Sleeping Mat Review

Nailing down your sleep system is one of the most important elements of a backcountry adventure, and this is even more crucial when venturing above the treeline in winter. Ever the innovator, Nemo has raised the bar once again with the latest addition to their ultralight sleeping mat range: the Tensor Extreme Conditions. With an R-Value of 8.5 (yes, you read that correctly) and weighing under 600 grams, Nemo claims that this the warmest, most insulating ultralight pad on the market. And it’s hard to disagree with. I put the Tensor EC to the test on a five day cross-country skiing trip in Kosciuszko National Park, and was suitably blown away by the sheer warmth and comfort it provided in sub-zero temperatures.

Nemo Tensor Extreme Conditions Specs

• Price: $419.95
• R-Value: 8.5
• Minimum Weight: 505g
• Packed Weight: 587g
• Mat Dimensions: 183 x 51 cm
• Packed Dimensions: 25.5 x 10 cm dia
• Thickness: 8.89cm
• Materials:
  • Top: 20D GRS certified Nylon
  • Bottom: 40D GRS certified Nylon, bluesign® approved
  • Insulation: Aluminised Film
• What’s Included? Vortex™ Pump Sack, Drawstring Stuff Sack, Velcro Strap, Repair Kit
• Available Sizes: Regular (above), Mummy, Regular Wide, Long Wide

Construction

The build quality of the Tensor Extreme Conditions is outstanding. Insulation is constructed using Nemo’s Apex™ baffles, which suspend four layers (8.89cm) of insulating Thermal Mirror™ metallised film inside the pad. Each layer reflects back body heat and helps block radiant heat loss to keep you toasty warm throughout the night, and their free-floating placement helps reduce that loud crinkle noise usually found with traditional air mats.

The outer materials are equally impressive. Nemo has upgraded the bottom material from 20 to 40D nylon which improves durability and puncture resistance to protect it from the rough terrain that you’re likely to encounter on remote backcountry trips. They’ve maintained the 20D nylon on the top side to provide a soft and lightweight surface that ensures a comfortable night’s sleep. In true Nemo style, the face fabrics are responsibly sourced and produced. The nylon is both 100% recycled (Global Recycled Standard certified) and bluesign® approved, which means it has met a number of strict requirements to minimise environmental impact.

Put simply, every element of this mat has been carefully considered throughout the design process. And you don’t need to take my word for it – this sleeping mat won an ISPO Award last year for its groundbreaking innovation. I can’t speak to its longevity yet, but I’ve owned a lot of sleeping mats in my time, and this one is so expertly crafted that I would expect to hold onto it for many years and adventures to come.

Use Case

So, now that we’ve established this is a technically impressive mat, let’s get down to whether or not it actually performs in the field. And what better way to test it out than a five day family backcountry ski trip? As an introduction to cross-country skiing for my two teenage daughters, we decided to venture to Munyang  Valley in Kosciuszko National Park, using the network of huts to set up bases next to which we would pitch our tents . 

Due to a lack of snow, followed by blizzarding conditions and a large dump of fresh snow, we had to divert from our original plan, but this resulted in three nights spent camping next to Schlink Hilton at 1780m elevation where the temperature dropped to below -5°C overnight. So yes, it was definitely cold – but by no means was I testing this mat to its absolute limits. It’s built to stand up to the most extreme environments, and, although temperature ratings are not assigned to sleeping mats, this one can undoubtedly handle well below -10°C. We then spent the remaining two days/one night exiting via Horsecamp Hut where we set up camp amongst  the snow gums.

In terms of size, I opted for the regular length and width (183 x 51cm). Given my height, the long length would’ve been the best option, however my winter tent (the Wilderness Equipment First Arrow) can’t accommodate anything wider than this. If I’m lying flat then my feet hang off the end, but this wasn’t a notable issue since I’m a side sleeper.

Quality of Sleep

Warmth

When it comes to warmth, it should be noted that I am a cold sleeper. When I’m sleeping in bitter winter conditions, I employ every trick in the book (filling a Nalgene full of hot water before I go to bed is a personal favourite). Suffice to say, I was pretty excited to try the Tensor EC because of its most impressive feature – the incredible 8.5 R-value. In fact, it’s the first sleeping mat ever to achieve an R-Value above 8. 

And it did not fall short. The Tensor EC was incredibly warm compared with any other sleeping mat I have used in the snow. Even as a side sleeper, I didn’t feel the slightest bit of cold through this during the night. Usually on winter alpine trips, I’ll bring along a closed cell foam pad as a back-up or extra layer, but there was virtually no need. In fact, if the temperature was any warmer, I think I would’ve been too hot with my winter -7°C rated sleeping bag. Although it goes without saying, this mat is not recommended for summer. It should be reserved for the coldest trips of the year where the evenings dip at least below 10°C. Otherwise, you’ll simply have an uncomfortable night’s sleep. But for its specified purpose, this mat is an absolute winner.

Comfort

The Tensor EC was also incredibly comfortable. As a side sleeper, 8.89cm of stable cushioned loft was a luxury and I felt no cold spots at all throughout the night. The nylon provides a decent surface to sleep on and I stayed rooted in place all night. I slept well on this mat all four nights of the trip, which as we all know is crucial for high-energy adventures. For an ultralight sleeping mat, I have absolutely no complaints about the level of comfort it provides.

Noise

We’re all familiar with that crinkle sound that’s so common with inflatable sleeping pads, which can be irritating on those nights when you just can’t seem to get comfortable (or even worse, when you’re sharing a tent with a restless sleeper!). The free-floating placement of Thermal Mirror™ layers is designed to eliminate this. Nemo claims that the Tensor EC is the quietest pad in its class, and I have no reason to disagree. I can’t say that I noticed the noise level, but this can only be a good thing. And perhaps most important of all, neither did my wife who was sharing the tent with me. Obviously it isn’t silent, compared, for example, with a closed cell foam pad that has virtually no noise. But for its category, there was no excessive noise that could impair your ability to get a full night’s rest.

Ease of Use

Weight & Packed Size

Part of what makes the Tensor EC so exceptional is the weight and packed size. For a mat with an R-Value of 8.5, it really is in a class of its own. At 587 grams packed weight, it’s perfect for those of us who want to minimise weight without sacrificing performance. For those who are counting every gram, you can eliminate the stuff sack and pump bag to shed that to a meagre 505 grams. Now obviously there are lighter mats on the market, but the insulation you’re rewarded with for a product this light in weight is like nothing I’ve tried before. It also took up minimal space in my pack – when packed in the stuff sack, the size is comparable to a 1L Nalgene water bottle.

Inflation & Adjustability

In terms of inflation, it quite literally couldn’t be easier. The Tensor EC comes with Nemo’s Vortex™ pump sack which is very easy to use, allowing you to pump it up in just a few breaths – a welcome relief in chilly high-altitude conditions. The LayLow™ Valve is streamlined and allows for micro-adjustments to the inflation level so you can customise it to your preference. I personally prefer to inflate as firm as possible in case of air loss, so I didn’t use this feature, however Nemo has noted that the valve has been optimised on the Tensor EC for colder conditions (even at -29°C and below!). There was no observed air loss overnight over the four nights that I used this sleeping mat, so I’ll definitely be giving the customisation feature a try next time.

Deflation & Packability

Deflating the Tensor EC was just as easy, using the LayLow™ valve to release most of the air and simply folding the mat neatly to pack it down. Nemo has recently moved away from generously sized stuff sacks, which are now cut to the precise dimensions of the item. I personally don’t have an issue with this, as it allows you to pack the item down to the smallest size possible and therefore saves on precious pack space. It does require a bit more effort as you have to remove the air completely and roll it up as tightly as possible. There is always the option to not use the stuff sack and simply wrap it with the velcro strap, but bringing the stuff sack along means you can both pack it down small and keep the repair kit together with the mat.

I wouldn’t hesitate to recommend the Tensor Extreme Conditions sleeping mat to anyone looking for an ultralight yet super warm addition to their winter sleep system. As Nemo claim themselves, the Tensor EC truly “toasts” the competition. This innovative piece of kit simply doesn’t compare to any other mat out there – it’s in a class of its own. For any form of winter camping, the Nemo Tensor EC is an exceptional performer, and has firmly planted itself as my go-to mat for cold weather expeditions.

Browse the full Nemo Tensor Range at Paddy Pallin

If you’re heading out in less extreme conditions, Nemo has updated their entire Tensor Ultralight range, with the new Tensor Trail (R-Value 2.8) for three-season adventures, and Tensor All-Season (R-Value 5.4) for year round trips.