Therm-a-Rest NeoAir XTherm NXT

Comfort is the weak point of the Therm-a-Rest XTherm NXT. The pad uses horizontal baffles, which I do not find comfortable for pressure relief. When lying on my side with the pad fully inflated, I often get pressure points on my hip and shoulder and my arm goes numb. When lying on my back, the pad does not contour to my body and I occasionally get some lower back soreness - it feels like lying on a board. The top material of the pad is not soft or stretchy and is not very comfortable to lie on with bare skin. The top is also a little slippery to lie on and sleeping bags will slide around on the pad.

With some pads, I will not inflate the pad fully (usually to around 70-80%) to improve pressure relief and comfort. But the XTherm is a winter pad and it needs to be fully inflated to maximize warmth. If you are not needing to maximize the pad's warmth, letting a little air out adds some comfort. But even when slightly deflated, the XTherm is not a comfortable pad.

The pad has decent stability, especially when fully inflated. Lying in the middle of the pad on your side or back feels particularly stable. When moving to the edges of the pad, stability decreases and it can feel like you are falling off the pad (especially if the pad has been deflated). Because of the stability of the XTherm, I find the 63.5 cm (25 in) wide widths of the pad to be the most comfortable. The XTherm comes in three sizes: regular, regular wide, and long wide. All sizes are 7.6 cm (3 in) thick. There is also a Max version of the XTherm where the only difference is the two sizes are rectangular shaped.

Warmth is where the Therm-a-Rest XTherm NXT is exciting. The XTherm has an ASTM-tested R-value of 7.3 and Therm-a-Rest positions it as a winter pad built for very cold conditions. The pad uses two technologies for insulation: layers of reflective film reflect heat back to the body (preventing radiative heat loss) and the Triangular Core Matrix creates triangular pockets of air, reducing air movement, preventing convective heat loss, and keeping a layer of warm air close to the body.

I have used the XTherm on glaciers, on snow, and on frozen ground down to -30°C (-22°F) with no additional ground insulation and stayed warm. With a foam pad underneath, I have gone down to -50°C (-58°F) and stayed warm. The insulation technologies Therm-a-Rest uses in the XTherm are very effective. This is the warmest pad I have used in the backcountry and it has by far the best warmth-to-weight ratio of any pad on the market.

The Therm-a-Rest XTherm NXT weighs 567 g (1.3 lb) on my scale for the long wide size, which matches the advertised weight. The regular wide is listed at 539 g (1.2 lb) and the regular at 440 g (15.5 oz). For a pad that stays warm at -30°C (-22°F), that is remarkably light and it is the reason the XTherm has the best warmth-to-weight ratio on the market.

Therm-a-Rest lists the packed size of the long wide and regular wide at 28 cm (11 in) by 13 cm (5.1 in), and the regular at 23 cm (9.1 in) by 11 cm (4.3 in). Packing the pad away is harder than most, and that is covered under Ease of Use.

The Therm-a-Rest XTherm NXT uses Therm-a-Rest's proprietary WingLock valve, a twist valve for both inflation and deflation that sits off the side corner of the pad at the head end. I like it, but it is not the best valve on the market. There are easier valves to use. It does allow fairly easy inflation and fairly easy deflation. Getting air into the pad is easy but deflating the pad to pack away is more difficult because of the Triangular Core Matrix. Air movement is slowed down, so the pad has to be rolled first to push the air out, then folded and rolled again to fit in its bag.

The pad comes with an inflation sack, a stuff sack, and a field repair kit. The inflation sack is pretty useless because the seams are not sealed and the material is air permeable, so a lot of air escapes the bag as you try to push air into the pad. The bag often pops off the valve mid-inflation as well. I almost always use a pad pump instead to inflate the XTherm and most pad pump manufacturers have an attachment compatible with the WingLock valve.

Durability is a strength of the Therm-a-Rest XTherm NXT. The common failure points on a sleeping pad are valve failures, delamination, baffles blowing out, and punctures. The XTherm uses a 70-denier nylon on the bottom, which is very effective at preventing punctures, and a 30-denier ripstop nylon on the top, where less puncture resistance is needed. The welds on the seams and baffles are very strong and I have seen very few instances of baffles blowing out on this pad.

The valve is robust, works well in cold winter conditions, and is replaceable. If the valve fails, the valve can be replaced and the pad kept in use, which is rare for sleeping pads today.

I have had no issues across multiple XTherm pads over the years and reviews online show very few durability problems. Therm-a-Rest covers the XTherm with the same limited lifetime warranty as its other pads.

Noise is the one area where the Therm-a-Rest XTherm NXT still lags behind other pads. Therm-a-Rest claims the newest XTherm version is quieter than earlier versions and I found that to be true. The XTherm will probably not wake anyone else in the tent or at the campsite, but the crinkle noise of the internal reflective film is noticeable when shifting positions. It is a moderately noisy pad.

The Therm-a-Rest XTherm NXT is for anyone who needs a very warm pad for extreme conditions and a winter pad that simply works. I go on many remote winter expeditions and, when I need something that is going to work, I take the XTherm - no other pad compares. It is not for anyone who prioritizes comfort, since it is not a comfortable pad. But if warmth-to-weight is your top priority, the XTherm is an amazing choice.