UKH

Insulated Inflatable Sleeping Mats Group Test

In cold weather it doesn't matter how good your sleeping bag is; without sufficient insulation underneath too, you are likely to suffer. If you're choosing one sleeping mat for year-round camping or mountain bivvies, make it a warm one. Modern insulated inflatable mats provide excellent warmth for a reasonable weight. But not all mats are created equal, with varying levels of insulation, comfort, weight, price and packability on offer. Here we compare five models across a range of budgets.

Mats group test, 247 kb

Our requirements for this test were simple: maximum warmth at for as little weight as possible. We wanted a mat that's minimalist enough for lightweight backpacking or alpine bivvies, but still warm enough for UK winter camping or even, at the extreme end, expedition use. So do they deliver...?

Overall summary

Alpkit

Airo 180

Alpkit table, 113 kb

Price: £49

Weight: 605g

R-value: unavailable

Comfort

40%

Warmth

30%

Weight

60%

Price

100%

Overall


Klymit

Insulated Static V

Klymit Insulated Static V, 191 kb

Price: £64.95

Weight: 690g

R-value: 4.4

Best in Test Good Value Large, 10 kb

Comfort

80%

Warmth

60%

Weight

50%

Price

100%

Overall


Exped

DownMat HL Winter M

Exped DownMat HL Winter , 206 kb

Price: £205

Weight: 486g (M)

R-value: 7

Best in Test Large, 13 kb

Comfort

100%

Warmth

100%

Weight

100%

Price

40%

Overall


Therm-a-Rest

NEOAir Xtherm

Therm-a-Rest NEOAir Xtherm, 168 kb

Price: £185

Weight: 453g

R-value: 5.7

Best in Test Highly Recommended Large, 14 kb

Comfort

100%

Warmth

80%

Weight

100%

Price

50%

Overall


Sea to Summit

Comfort Plus Insulated

Sea to Summit Comfort Plus Insulated, 192 kb

Price: £180

Weight: 740g (Reg)

R-value: 5

Comfort

80%

Warmth

70%

Weight

30%

Price

50%

Overall


What's an R-value?

This is a measure of how effectively something resists conductive heat flow: a bigger R-value means better thermal insulating properties. Where available we've included the quoted R-values of these mats, which we consider a more reliable guide to insulating performance than the slightly nebulous temperature ratings that are often also provided.

By way of comparison: the Therm-a-Rest Original Z-Lite, a benchmark mountaineer's closed cell foam mat, has an R-value of 2.2, while among the inflatable mats for which data is available in this review the lowest R-value is 4.4

Alpkit Airo 180 £49

A foam-filled inflatable mat of a very familiar style, what the Airo lacks in thickness, lightness and temperature performance it compensates with value for money and general no frills robustness. If you want something for general camping and less rigorous 2-3 season hill use, and don't fancy splashing too much cash, it's a winner.

Alpkit Airo 180, 176 kb
Alpkit Airo 180
© UKC Gear

Warmth and comfort

Its depth of only 2.5cm inevitably limits the Airo's warmth and comfort. While it is thick enough for happy camping on fairly flat ground, close-cropped turf for instance, the Airo 180 is still a lot thinner than the other inflatable mats in this test, and you'll soon find its comfort limits on uneven ground.

Warm & comfy enough for general camping, but neither as warm nor as fat as the rest on test , 215 kb
Warm & comfy enough for general camping, but neither as warm nor as fat as the rest on test
© Dan Bailey

The foam fill provides some insulation as well as cushioning, but not a huge amount. We'd consider this a 3-season mat, at most; for winter or high mountain use it's simply not warm enough, though we've been fine with it on chilly spring nights. Exactly how warm is it? No figures are available, but Alpkit guesstimate an R-value of 2 or 2.5, which sounds about right to us. We would not recommend this mat as a first choice for anyone aiming to camp regularly in temperatures around or below freezing point; it's better viewed as a budget choice for general valley camping and less-rigorous hill use.

Shape and dimensions

The Airo 180 has a foam fill and a familiar two-way twist valve , 184 kb
The Airo 180 has a foam fill and a familiar two-way twist valve
© Dan Bailey

To save unnecessary weight the Airo has a tapered mummy shape, though the taper is more gradual than some models in the review, which makes for slightly more leg/foot room. The official dimensions of the 180 are a length of 180cm and a width of 52cm at its widest point, but measuring just the foam (rather than the crimped fabric edges) its effective width at the shoulder is closer to 50cm. Because it's a flat surface rather than ridged or dimpled, like the other mats on test, you can use all of the space on the Airo, which may help it feel larger than it really is.

Fabric

With a 40 denier ripstop nylon, the Airo 180 feels good and tough, but should you make a puncture then a small repair kit is included (though there's no special sleeve for this in the stuffsack, as offered by some other brands). Its shiny surface makes the Airo very slippy on a groundsheet or sleeping bag, so if pitched on a slope you might well wake up against the wall of the tent.

It's fatter than most when rolled away (750ml bottle for scale), 189 kb
It's fatter than most when rolled away (750ml bottle for scale)
© Dan Bailey

Weight and pack size

A weight of 605g (plus 17g for the stuffsack) is far from being the last word in ultralight, and the warmth:weight ratio is nothing to write home about either. Nevertheless, for warmer weather campers who only occasionally intend to carry an overnight load into the hills it will doubtless prove acceptable enough, especially given the affordable price. Considering the Airo's thinness, the packed size seems relatively bulky - indeed it's the biggest of the models on test when rolled away. To an extent you get what you pay for here. For those looking to save weight, a 2/3 length Airo 120 is also available, though for most of us that's only going to be long enough for the torso and not the legs too.

Inflating and deflating

Inflating the Airo 180 takes only a bit of puff, 246 kb
Inflating the Airo 180 takes only a bit of puff
© Dan Bailey

Though Alpkit say 'self-inflating' we'd suggest the Airo 180, in common with most foam-filled mats of this sort, does actually need a fair bit of puff to help it on its way. Leave it with the valve open for a few minutes and it gets part way there on its own, in our experience then only needing eight or so good big blows to finish it off. Operating via a single conventional twist valve, it is easy enough to inflate. As is usually the case with this sort of design the foam fill makes it a bit of a struggle to deflate, but once you've managed to squeeze the air out the mat fits easily into its stuff sack. Elastic loops are provided to help make packing a bit neater.

Liberal use of knees is required to deflate and roll it up, 230 kb
Liberal use of knees is required to deflate and roll it up
© Pegs Bailey

Alpkit say:

Full length lightweight and compact self-inflating mat. The Airo 180 is perfect for any trip where minimal weight and small pack size are paramount - but you still need the insulation of a foam mat. The challenges you are taking on mean compromises will need to be made but the Airo 180 will help minimise your losses. The tapered design, lightweight fabric and aggressive die-cut foam trim the mat down so that there is no excess weight. If you are after something lighter try the shorter Airo 120.

  • Price: £49
  • Weight: 605g (our measure)
  • Dimensions: 180 x 52cm
  • Thickness 2.5cm
  • R-value: no info available
  • Temperature limit: no info available
  • Fabric: 40D diamond Ripstop nylon
  • Insulation: Foam
  • Packed size: 13 x 27cm
  • 3 Year Alpine Bond
  • Single valve inflation/deflation
  • Aggressively die cut to save weight
  • Compression stuffsack and repair kit included

For more info see alpkit.com


Klymit Insulated Static V £64.95

This quirky-looking offering from Klymit may weigh a fair bit, but it manages to provide plenty of comfort and an effective 4-season's worth of insulation while still keeping the price down. Not one for climbing in the Andes perhaps, but would be fine on high mountain overseas treks or summer Alpine bivvies, and for UK winter hills in all but the very coldest weather.

Klymit Insulated Static V, 191 kb
Klymit Insulated Static V
© UKC Gear

Warmth and comfort

The Static V owes much of its warmth and comfort to its novel diagonal-ridged design. Its many baffles help to limit air movement inside the mat, say Klymit, thus keeping you warmer. In addition there's a layer inside of something called Klymalite, a synthetic insulation that is also designed to reduce the movement of air.

The deep grooves help your sleeping bag maintain its loft for extra warmth , 248 kb
The deep grooves help your sleeping bag maintain its loft for extra warmth
© Dan Bailey

Rather than the underside of your sleeping bag being compressed, as you'll find on a flatter mat, the distinctive deep grooves are there to help the bag loft. That last point sounds good in theory, though it is worth mentioning that the grooves run right through, so you effectively get no insulation from the mat at all in these areas. Given the mat's relatively hefty weight, the R-value of 4.4 is only respectable - some lighter (but considerably more expensive) models are a lot warmer. Nevertheless we've found it warm enough for cold camping, though we would probably draw the line at just below zero rather than the extreme cold of a hard winter. For an early spring loch-side bivvy in a light breeze, and temperatures that dropped to around freezing, the Insulated Static V was fine.

photo
Smoothing over a lumpy pitch
© Dan Bailey

photo
Warm enough for chilly camping
© Dan Bailey

All those V-shaped ridges make for a novel feel when you lie down, and while they are certainly not uncomfortable we did find them a bit odd at first. The idea is that they offer support in whatever orientation you sleep, while the ruffled 'side rails' are said to help keep you centred on the mat. We think it's most comfy when lying on your back, and we can't honestly say the side rails make a difference. At just under 6.5cm this is a deep mat, and though it is quite floppy there's something about the way the baffles mould themselves around uneven ground that helps to give you a well-cushioned night's rest on all but the roughest terrain. We had occasion to push its limit recently on a very rocky pitch in Coire an t-Sneachda - we're talking several humps like the tops of part-buried footballs. The Static V did a good job of smoothing over the lumps, and in that capacity only the thicker, more rigid Therm-a-Rest and Exped models would have fared better.

Shape and dimensions

Interesting ridged design, and robust twist valve, 178 kb
Interesting ridged design, and robust twist valve
© Dan Bailey

Its oblong shape gives you more sleeping space than a mummy-shaped mat, which is great for car camping, basecamp use, a larger person or indeed anyone who tends to roll about in their sleep. At nearly 183cm long and over 58cm wide, this mat has a larger surface area than the rest on test, too. The obvious drawback is the increased weight and bulk when it comes to carrying it up hills; it might have been good if Klymit also offered a mummy-shaped version of the Static V.

Fabric

You clearly pay a weight penalty for it, but its super-thick 75 denier polyester does make the Static V a tough customer, and we've found it well up to some rough treatment on camps and bivvies. But if you did manage to damage it - less likely than most mats - then a small repair kit is included, tucked into a pocket in the stuffsack. The soft underside of the mat seems to help reduce the dreaded groundsheet slip, too, which is a positive advantage when camping on a slope (read: most of the time).

Weight and pack size

Not too big when packed away: 230g gas cartridge and 750ml water bottle for scale, 206 kb
Not too big when packed away: 230g gas cartridge and 750ml water bottle for scale
© Dan Bailey

It is durable, comfy and warm for its price, so where's the catch? Something had to give, and the downside to the Static V is its weight. At 690g (plus another 15g for the stuff sack), this is one of the heaviest mats on test. It's slightly bulkier in the pack than the lighter mats in the review, too, but not by a lot. The best of the rival models are both considerably warmer and a lot lighter, and for cold weather campers who are especially keen on counting grams both will be a major consideration. Ultralight backpackers and fast-and-light mountaineers will probably want to look elsewhere. Less weight-conscious campers may find this price worth paying for such a durable mat though, especially if they're not keen to shell out the extra premium for a lighter insulated model.

Inflating and deflating

Inflates in 10-15 breaths? We say more like 20..., 153 kb
Inflates in 10-15 breaths? We say more like 20...
© Dan Bailey

The mat is not self-inflating, but is puffed up and deflated via a single valve. This operates with a simple pull mechanism, and can also be twisted to lock it closed so there's no danger of accidental deflation in the night. Klymit claim it can be inflated in 10-15 breaths, but they must have huge lungs; we reckon 20. The outward pressure on the valve is such that you can't remove your mouth from it for an instant - some other blow-up valves are a bit more relaxed in terms of the amount of air they let out. As a result you can feel pretty light headed by the time the mat is inflated, and this would be particularly noticeable if you were camping at high altitude. The upside to this is that deflation is extremely fast, so the whole thing can be rolled away in a couple of minutes tops. Klymit have provided a realistically sized stuffsack, so there's no struggle to get the mat packed into it.

Klymit say:

Klymalite lofted synthetic insulation creates additional warmth that lasts through the night. Take on cold conditions without sacrificing comfort or pack size. Klymalite lofted synthetic insulation in the pad offers exceptional warmth without the dreaded crinkle noise of other insulated pads. The exclusive V-Chambers and dynamic side rails also limit the movement of air, helping warmth stay closer to the top of the pad—meaning closer to you.

  • Price: £64.95
  • Weight: 690g (our measure)
  • Dimensions: 182.9 x 58.4cm
  • Thickness: 6.4cm
  • R-Value: 4.4
  • Temperature limit: no info available
  • Inflation: 10-15 Breaths (we'd say more like 20-25)
  • Pack Size: 12.7cm x 20.3cm
  • Fabric: 75D Polyester
  • Warranty: Klymit Lifetime Warranty
  • Patch Kit included for emergency repairs

For more info see klymit.com


Exped DownMat HL Winter M £205

With an unrivalled warmth:weight ratio and superb comfort, this is a worthy winner of Best in Test. The eye-watering price is its only downside, but this does reflect the use of down insulation, and the complicated internal baffling that this requires. If you're going somewhere seriously cold then this is the mat for you.

Exped DownMat HL Winter , 206 kb
Exped DownMat HL Winter
© UKC Gear

Warmth and comfort

Exped produce a bewildering array of different but fundamentally quite similar-looking mats (the almost identical names don't help). This one has the best warmth:weight ratio of the lot - in fact Exped claim it to be "the world's lightest mat at comparable warmth and comfort levels". All such claims should be treated with a small pinch of salt, but we are certainly not in a position to question it. In our experience this is a seriously warm mat, and one that comes in at a surprisingly light weight.

The honeycomb pattern helps make the fabric non-slip, 265 kb
The honeycomb pattern helps make the fabric non-slip
© Dan Bailey

The insulation is hard to argue with - a layer of 700 fill power goose down (ethically sourced), which gives you superb levels of warmth for minimal weight. Even the best down sleeping bag will compress beneath you, compromising its insulation, but because Exped's DownMats hold their feathery filling inside deep inflated baffles, the loft is maintained and you are protected from the cold ground beneath. In the Medium size you get 132g of down fill, but it's what you do with it that counts more. Here's what Exped's UK distributor told us:

'The weight of down in Exped mats shouldn't be thought of in the "traditional" sense that we do in a sleeping bag or jacket. In a sleeping bag the fill has to "force" the two sides of fabric apart to create loft/space; but in the Exped mats the inflation pump creates the space for the down to fill. The positioning of the down is critical, as is the divider design to keep it in the right place.'

Provided the mat stays dry then it has an R-value of 7, an impressive number which according to Exped equates to performance down to -32C. Despite a cold winter here in the UK, we've not got close to pushing this lower limit. We have however comfortably slept out on a couple of Scottish winter nights in sub-zero conditions, and more recently a high level spring camp where the temperature wasn't far above freezing and the wind relentless. It is safe to assume that any conditions you can imagine in the UK will be well within the DownMat HL's comfort zone, and having used a previous Exped down-filled mat in minus-double-digits in the Andes we'd have no qualms in recommending the HL for expedition use in very cold places! If your ambitions are less extreme then the DownMat could still have a place, since it may permit a thinner sleeping bag to be used.

Its whopping 9cm thickness and relative rigidity both help to give the DownMat HL a very comfy, supportive feel. Riding high over the lumps, it's easy to forget how uneven the ground beneath you actually is. When it comes to kipping on rough terrain, if there is a more comfortable lightweight mat on the market then we've yet to use it. The broad vertical baffles help keep you centred on the mat even if you're a side sleeper or tend to roll about in the night, and this goes a long way to compensating for the mat's relative narrowness (see below).

Shape and dimensions

photo
Downmat HL in Glen Coe
© Dan Bailey

photo
One valve for both inflating & deflating
© Dan Bailey

This mat comes in three sizes, Medium, Medium/wide and (for real giants) Long/wide. Medium might be the smallest, but at 183cm long it's exactly the same length as our 6-foot reviewer; anyone much shorter than this is going to have some spare mat to play with (and carry). Given the weight saving it would offer, it's odd that a shorter version isn't available. With a width of 52cm at the shoulder and only 35cm at the foot (in standard size M), the mat has quite a radical taper - in fact it is the pointiest of the models on test. We've found the width just adequate for a comfy night's sleep; the reviewer is fairly broad, a size L in clothing terms, and anyone wider than that would probably be better off going up a size. This mummy-shaped design reduces unnecessary weight and packed size, and if you're on the move every night or only out on a short trip then that's a definite plus. However for extended basecamp use you might prefer a more generous oblong shape - Exped do also make these with down fill.

Fabric

Outside it's a skimpy 20 denier polyester, which on the top side has been coated with a patterned finish to make it less slippy against a sleeping bag, while the underside has minimal slide on a groundsheet too - top marks to Exped here. This is quite a lightweight fabric for the punishment that a mat receives, which may be good if you're carrying it but does have durability implications. On a previous review some years ago we managed to tear the identical fabric of another Exped DownMat model surprisingly easily, and since then would always carry the repair pack that comes supplied - it fits in a sleeve in the stuffsack, it doesn't weigh much, and it's easily used even in a tent.

Weight and pack size

In size M it's one of the more compact mats on test, 250 kb
In size M it's one of the more compact mats on test
© Dan Bailey

At just 486g, the Downmat (size M) is extremely light for the insulation on offer - Add 13g for the stuff sack and 58g for the obligatory Pumpbag (more on that below) and you're still quids in when it comes to weight saving. The mat fits easily into its stuff sack, but only with a bit of persuasion can the Pumpbag be crammed in too. In its pack it's about 25cm long, making it one of the most compact of the models on test.

Inflating and deflating

The Schnozzel Pumpbag sounds dodgy, but works a treat, 155 kb
The Schnozzel Pumpbag sounds dodgy, but works a treat
© Dan Bailey

The Downmat inflates/deflates via a single valve, a robust and effective system that Exped have used for years (we've always liked it). To avoid the down fill getting damp and degrading over time, Exped recommend that you never blow the mat up with your breath but only ever with the 'Schnozzel Pumpbag' that comes included. This horrendous-sounding item is nothing more sinister than a drybag-style nylon sack. It is easy to use: plug it into the valve, flick it full of air, roll the closure tight and squeeze... It depends how full you can get the bag, but in our experience four or five bags-worth tends to be enough to fill the mat. This system is a little more fiddly than simply blowing through a valve, but on the plus side it doesn't leave your head spinning (a definite advantage if you're at altitude!). The Pumpbag can also be enlisted as an impromptu pillow, though in this role it works better stuffed with clothing than full of air. To deflate the mat, a little toggle is popped into the valve to hold it open, and then you simply squeeze and roll - it's quick and easy.

Exped say:

The DownMat HL Winter is the world's lightest mat at comparable warmth and comfort levels! It is extremely compact when packed and features a tapered shape that fits into the smallest of tents. It includes the Schnozzel Pumpbag UL M. Next-to-skin comfort and anti-slip GripSkin honeycomb-pattern coating. Laminate is air tight and impervious to hydrolysis. Down certified by RDS, a stringent animal welfare standard.

  • Price: £205
  • Weight: 486g (size M, our measure)
  • Sizes: Medium, Medium/wide and Long/wide
  • Dimensions (M): 183 x 52cm (foot width 35cm)
  • Thickness: 9cm
  • R-value: 7
  • Temperature limit: -32C
  • Top: 20 D Polyester, TPU polyether film laminate, hydrolysis resistant, Honeycomb Gripskin coated, Oeko-Tex 100 certified
  • Bottom: 20 D Polyester, TPU polyether film laminate, hydrolysis resistant, Oeko-Tex 100 certified
  • Insulation: 700 fill power goose down, IDFL certified, RDS (Responsible Down Standard) certified

For more info see exped.com


Therm-a-Rest NEOAir Xtherm £185

The lightest mat on test and also the second warmest, the NEOAir Xtherm would be a superb choice for anyone looking for a UK winter, alpine or expedition-worthy insulated mat with the lowest possible weight. The horizontal baffles won't be everyone's favourite, and it is very loud, but it doesn't feel like a mat you have to handle with too much care.

Therm-a-Rest NEOAir Xtherm, 168 kb
Therm-a-Rest NEOAir Xtherm
© UKC Gear

Warmth and comfort

Unlike a mat that uses down or synthetic fill, the NEOAir Xtherm relies for its warmth on something called 'Thermacapture technology'. This is a series of reflective layers designed to trap radiant heat. Couple this with the so-called 'Triangular Core Matrix' (everything needs a name, it seems) which reduces convective heat loss, and the result is a lot of warmth for minimal weight.

The NEO Air on a winter bivvy, 161 kb
The NEO Air on a winter bivvy
© Dan Bailey

Indeed, Therm-a-rest boast that it has the greatest warmth-to-weight ratio available in any air mattress by far. We can't verify this claim, but it's worth pointing out that the Exped mat in this review is only 30g or so heavier and has better insulation performance. Nevertheless with an R-value of 5.7 for a weight of only 453g the Xtherm's numbers are certainly impressive. What does that equate to in terms of temperature rating? A chart on the Therm-a-rest website implies it could take you down to -40. You'd be unlikely to put that lab-based result to the test in UK use, but the real world performance of a mat will depend on numerous factors in any case, not least the quality of the sleeping bag it's paired with. On a snowy bivvy during the Beast From the East, where minus-double-figures night time temperatures were exacerbated by a considerable wind chill, the NEOAir Xtherm gave our reviewer a warm and comfortable night's sleep - and at just over 450g you can't argue with that. On the strength of our experience, this mat should be more than adequate for most mountain and cold weather use worldwide.

Since they run at 90 degrees to your body, the horizontal baffles can take some getting used to; we're not as keen on them as vertical ones, though they're soft enough. It's worth mentioning too that the insides of this mat crinkle and rustle audibly as you shift around, something that might annoy a light sleeper.

It's deep, warm and comfy... but perhaps a little narrow, 263 kb
It's deep, warm and comfy... but perhaps a little narrow
© Dan Bailey

Shape and dimensions

The NEOAir Xtherm comes in two sizes. At 183cm in length, Regular is long enough for anyone of about 6 foot or under (weight-conscious shorter users might justifiably wonder why no size Small is on offer); but at only 51cm at its widest (in fact we make the effective width on top more like 49cm) and with quite a tapered shape, the mat does feel on the narrow side. With a depth of just over 6cm it sits quite high off the ground, and some users in this review said that this does feels a bit precarious in combination with its narrowness; the fact that the baffles aren't aligned to help you keep centred on the mat may not help in this regard.

30D ripstop top fabric, and familiar twist-lock air valve, 152 kb
30D ripstop top fabric, and familiar twist-lock air valve
© Dan Bailey

Fabric

On the top side, a 30D ripstop nylon seems a like a good compromise between toughness and weight saving; but it's more often the underside of a mat that takes the punishment, and here Therm-a-Rest have sensibly used 70D. When bivvying in the mountains, unless it's on snow, you do have to treat an air mat with care - but the NEOAir perhaps less than most. The top side is fairly soft next to the skin, and not too slippy on a sleeping bag; the smooth underside does skate around readily on a groundsheet though, particularly side-to-side in the direction that the baffles are aligned - we could find this irritating when camping on an incline.

Weight and pack size

Extremely light and compact for a mat of this warmth, 262 kb
Extremely light and compact for a mat of this warmth
© Dan Bailey

A weight of only 453g (size regular) would be impressive for any inflatable mat, but for one that offers an R-value of 5.7 it is worth writing home about. For ultralight backpacking in winter, fast-and-light alpine fun or full-on expedition use, this is a definite advantage, and we'd have no hesitation recommending the NEOAir for all cold weather pursuits. When deflated the mat basically feels like an empty bag, without the extra bulk that you get with a conventional insulated fill, and it can be rolled tighter than the other mats on test. In fact the stuff sack is quite a lot wider than it really needs to be. It's worth pointing out that the pump bag that comes with this mat weighs 55g, which will nudge your overall weight just over 500g all-in.

Inflating and deflating

Inflating it with lung power alone leaves you a bit dizzy (I'd left the pump bag at home), 165 kb
Inflating it with lung power alone leaves you a bit dizzy (I'd left the pump bag at home)
© Dan Bailey

This mat is not self-inflating to any extent, but has to be entirely blown up by the user via a single twist-lock valve. The NEOAir's layered insulation is clearly less susceptible to moisture than, for instance, the Exped's down fill, but to avoid any issues with condensation and mould buildup inside, this mat comes with an inflator bag that can be used to pump it up. Thanks to its depth there's a lot of volume to fill, and we reckon it takes at least 8-9 bag-fulls. To get the mat up to full pressure you still then need it finish it off with your breath. If you leave the pump bag at home and rely on lung power all the way, it takes at least 25 hefty breaths - enough to leave you a little dizzy even at sea level. The valve itself is robust and secure. Because there's no foam inside to fight against, deflating this mat is easy, and it can be rolled away in a couple of minutes, though the valve is a bit smaller than some so this is not the quickest mat to deflate.

Therm-a-Rest say:

The XTherm air mattress delivers the greatest warmth-to-weight ratio available in any air mattress by far, with a softer, textured no-slip fabric for better next-to-skin comfort and a quieter rest. Multiple, reflective ThermaCapture™ layers give the XTherm™ air mattress true four-season warmth without the weight or bulk usually found in a winter-worthy mattress. Stuff sack and repair kit included.

  • Price: £185
  • Weight: 453g (regular, our measure)
  • Sizes: Regular and Large
  • Dimensions (regular): 183 x 51cm
  • Thickness: 6.3cm
  • R-Value: 5.7
  • Temperature limit: -40
  • Top: 30D rip HT nylon
  • Bottom: 70D nylon
  • Packed dimensions: (Reg) 23cm x 10cm
  • Insulation: Reflective Thermacapture technology traps radiant heat while Triangular Core Matrix construction minimizes convective heat loss
  • Advanced materials and a tapered design reduce weight without compromising warmth

For more info see thermarest.com


Sea to Summit Comfort Plus Insulated £180

An unusual double-layered, dimpled design makes the Comfort Plus Insulated a bit of a leftfield choice. It is certainly warm enough for UK winter mountain camping, but although it feels tough and well-built the considerable weight would be a big disadvantage on minimalist mountain trips. Given its weight, the price seems steep.

Sea to Summit Comfort Plus Insulated, 192 kb
Sea to Summit Comfort Plus Insulated
© UKC Gear

Warmth and comfort

The Comfort Plus is built differently to the other mats on test, using a matrix of dot welded spots to create a series of interconnected air chambers - Air Sprung Cells, as Sea to Summit call them.

'Air Sprung Cells operate in the same way as a pocket spring mattress' they say. 'As each cell deforms independently the mattress conforms to your body shape which feels softer and more comfortable with more body contact area and even dispersion of pressure.'

There may be something in this. For what is by the standards of this review only a medium-deep mat (no depth measurement is provided, but we make it around 5cm) the Comfort Plus surprisingly soft and padded. It's even good for side sleepers. However we've found it works best on flatter ground. The lower layer of air chambers can absorb only so much unevenness before it becomes noticeable, so if you lay it on very bumpy terrain (not always avoidable) then you will tend to feel the lumps more than with the other premium mats in this review. This is probably because it is very floppy, so where other mats provide a measure of support by virtue of their thickness and relative rigidity, the Comfort Plus more readily deforms to the ground below.

Warm enough to sleep directly on the snow, 118 kb
Warm enough to sleep directly on the snow
© Stewart B

Given its floppy feel the warmth on offer is perhaps something of a surprise, an R-value of 5 making this the third-best-insulating model on review. This is thanks in part to a synthetic fill which lofts up inside the cells of the mat to prevent convective heat loss from your body to the ground. Here's what Sea to Summit have to say about that:

THERMOLITE® HL-1 high loft insulation is a fiberfill constructed with a unique 3D crimp of hollow-core and solid fibers, which provide excellent lightweight warmth with superior durability.

Combined with this is a reflective metalised layer on the fabric, which is designed to bounce radiant heat loss back to your body. The net result is a mat that is more than adequate for winter use in most conceivable UK conditions. We have used it for a snowy bivvy during the Beast From the East, where minus-double-figures night time temperatures were exacerbated by a considerable wind chill: our reviewer was oblivious to the cold and enjoyed a happy night's sleep.

A warm, comfy mat for winter bivvies, but it's not a lightweight option, 177 kb
A warm, comfy mat for winter bivvies, but it's not a lightweight option
© Dan Bailey

Shape and dimensions

With a Small, Regular & Large available in both Mummy and Rectangular models, Sea to Summit offer a big range of choice with this mat. The Rectangular version would be better for car camping or basecamp use, while the Mummy is lighter for backpacking or mountain bivvies. We've had the size Regular Mummy on test, which measures 183 x 55cm (at its widest point). That's exactly as long as our reviewer; anyone significantly over 6 feet would want a size Large, while for shorter users it's good to know that some weight can be saved by opting for a Small. At its widest point this is one of the broader mats in the review, while the taper towards the feet isn't as sharp as some, so overall you get plenty of sleeping area - good news if you tend to roll about in the night.

Puffing it up with the 'Airstream Pumpsack', 214 kb
Puffing it up with the 'Airstream Pumpsack'
© Dan Bailey

Fabric

Sea to Summit have used a non-woven fabric called Exkin Platinum, with a TPU coating for abrasion resistance and toughness in the cold. We have no data on its weight or thickness, but with a ripstop pattern and a rubbery feel it seems pretty strong stuff. It is relatively quiet, so you don't crinkle like a crisp packet when rolling over, but with its shiny texture it does tend to slide on a sloping groundsheet.

Beside a 1 litre water bottle for scale, 241 kb
Beside a 1 litre water bottle for scale
© Dan Bailey

Weight and pack size

The warmth on offer here is pretty high, but you pay a penalty for that. Weighing in at a hefty 740g for a size regular, mummy shape mat (plus 60g for the 'Pumpsack' stuffsack), this is by quite some margin the heaviest mat on test. That alone will probably put off the more weight-averse user. For cold weather car camping this would be the business, but for mountain use where every gram counts it would be hard to recommend over lighter models. The weight might be considerably greater than the best in this review, but the price is more or less on a par. It feels robust though, and with a packed size of about 23cm long it's not too bulky in the bag.

Inflating and deflating

photo
Funky valve system
© Dan Bailey

photo
Finishing the inflation by lung power
© Dan Bailey

Uniquely in this test the Comfort Plus has a double layer construction, with inflatable chambers on both sides of the mat, each served via its own valve. The idea is that you can fine tune the inflation of the bottom and top layers separately, but is this a solution in search of a problem? We can only ever see ourselves wanting them both at maximum pressure.

An anti-microbial treatment on the fabric helps prevent mould or fungal growth inside, something of a risk with any mat that gets puffed up full of damp breath. While you can blow up the Comfort Plus straight from your mouth, it's still preferable not to introduce moisture into the mat. To avoid this a pump system is employed, with the stuffsack doubling as an 'Airstream Pumpsack'. You attach this to the valve, pull the bag out to its full extent, and then blow steadily into it (from a distance of 30cm to reduce the moisture in your breath). Once the bag is full you roll it up to push the air into the mat. With nearly 550 sprung air cells inside the Regular sized mat you might think this would take a while, but the overall volume is not great and we've managed to fully inflate each side of the mat with a single bag, only needing to finish the last bit with breath power. In fact this is one of the quickest inflations of the mats on test. The in/out valves are robust and very simple in use, a clever design consisting of layers of stoppers: it can either be closed, opened (one way) for inflation, or fully opened for quick deflation.

Sea to Summit say:

Our Comfort Plus Insulated sleeping mats with their dual layer construction provide the most effective system for fine-tuning the level of comfort available in any air mattress today. The two independent high-resolution cell layers give excellent support by distributing your body weight and shape over more cells. The two layers are also offset for more uniform insulation and cushioning. Because the two layers can be pressurized independently, the top layer can be inflated to your personal comfort, while maintaining a high-pressure base layer for protection from rough or uneven terrain. Both layers can be adjusted independently using the fine tune valve to get just the right level of softness and support.

  • Price: £180 (size regular)
  • Weight: 740g (size regular, mummy, our measure)
  • Sizes: Small, Regular & Large in both Mummy and Rectangular models
  • Dimensions (Regular Mummy): 183 x 55cm (max)
  • Thickness: 5.5cm (our estimate)
  • R-Value: 5
  • Temperature limit: no info available
  • Packed dimensions (Regular Mummy): 12 x 23cm

For more info see seatosummit.co.uk

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