Sleeping Pad R-Values of 2021

Sleeping Pad R-Values of 2021

A backpacking or camping sleeping pad’s R-value measures its resistance to heat loss to the ground when you lie on it at night. Pads with higher R-values do this more effectively than pads with lower R-values. R-value isn’t a measure of warmth per se, but of a pad’s ability to prevent the loss of the warmth that your body generates. It’s just like the R-value used to rate home insulation.

Sleeping Pad R-Values and Air Temperature in Degrees

What’s the correlation between air temperature and sleeping pad R-values? When do you need a pad with a higher R-value? This table is based on Exped’s recommendations in Fahrenheit and Celsius degrees.

Air Temperature (F):50433629221580-7-14-21-30
Minimum R-Value11.522.533.544.555.566.5
Air Temperature (C):1062-2-6-9-13-18-22-26-30-34
Minimum R-Value11.522.533.544.555.566.5

In addition:

  • R-values are additive, so you can combine two pads to increase your warmth level.
  • Women need higher R-values pads because they have lower body mass than men. An additional R-value of 1 is usually a good hedge for women and other cold sleepers

Sleeping Pad R-Value Standard

Last year (2020), the outdoor industry rolled out an international and industry-standard R-value test procedure called ASTM F3340-18. This means you can compare the R-values of different sleeping pads made by different manufacturers and know that they’re all using the same test procedure to measure the R-values of their pads. That’s a huge benefit for consumers and will eventually have the same impact that the adoption of standardized sleeping pad temperature ratings had for comparing sleeping bags from different companies.

The companies that have adopted the new R-value sleeping pad standard (ASTM F3340-18) and retested all of their current sleeping pads include:

  • Therm-a-Rest
  • NEMO
  • REI
  • Exped
  • Sea-to-Summit
  • Big Agnes

Klymit has also indicated that they will adopt the new sleeping pad R-value standard but has only listed one pad on their website with an ASTM F3340 rating. For details about the status of industry adoption, see below.

Sleeping Pad R-Value Comparison

The following table provides a side-by-side comparison of the  ASTM F3340-rated sleeping pads available in the US market. The pad weights listed are sized for 72″ long x 20″ wide pads, though there are a few exceptions below. The R-Value of a pad remains the same if you select a longer, shorter, or wider variation of the pad.

Make / ModelR-Value (F3340-18)Weight (Oz)ThicknessType
Therm-a-Rest NeoAir XLite4.2122.5"Inflatable
Therm-a-Rest NeoAir XLite Women's5.4122.5"Inflatable
Therm-a-Rest NeoAir XTherm6.9152.5"Inflatable
Therm-a-Rest NeoAir XTherm Max6.9172.5"Inflatable
Therm-a-Rest NeoAir UberLite2.38.82.5"Inflatable
Therm-a-Rest Basecamp6402"Inflatable
Therm-a-Rest LuxuryMap6523"Inflatable
Therm-a-Rest MondoKing 3D7704.25"Inflatable
Therm-a-Rest NeoAir Camper Duo2.5733"Inflatable
Therm-a-Rest NeoAir Venture2.2192"Inflatable
Therm-a-Rest Original Z Lite1.7140.75"Foam
Therm-a-Rest ProLite2.4181"Self-Inflating
Therm-a-Rest ProLite Apex3.8222"Self-Inflating
Therm-a-Rest ProLite Plus3.2231.5"Self-Inflating
Therm-a-Rest ProLite Plus Women's3.9221.5"Self-Inflating
Therm-a-Rest ProLite Women's2.7181"Self-Inflating
Therm-a-Rest Ridegrest Classic2140.625"Foam
Therm-a-Rest RidgeRest SOLite2.1140.625"Foam
Therm-a-Rest NeoAir Topo2.3233"Inflatable
Therm-a-Rest NeoAir Topo Luxe3.7234"Inflatable
Therm-a-Rest Trail Lite3.2261.5"Self-Inflating
Therm-a-Rest Trail Lite Women's4.5251.5"Self-Inflating
Therm-a-Rest Trail Pro4.4293"Self-Inflating
Therm-a-Rest Trail Scout3.1221"Self-Inflating
Therm-a-Rest Z Lite Sol2140.75"Foam
NEMO Switchback UL214.50.9"Foam
NEMO Tensor Alpine UL4.8173"Inflatable
NEMO Tensor UL Insulated3.5143"Inflatable
NEMO Tensor UL Non-insulated1.6133"Inflatable
NEMO Cosmo 3D3.3323.5"Inflatable
NEMO Roamer SI61204"Self-Inflating
NEMO Vector UL Non-insulated1.6223"Inflatable
NEMO Vector UL Insulated3.5253"Inflatable
NEMO Astro Insulated2.6243.5"Inflatable
NEMO Astro Non-Insulated1.5193.5"Inflatable
NEMO Astro Lite Insulated2.6183.5"Inflatable
NEMO Astro Lite Non-Insulated1.5143.5"Inflatable
NEMO Flyer3.3232"Inflatable
NEMO Quasar 3D Insulated3.3303.5"Inflatable
NEMO Quasar 3D Non-Insulated1.8243.5"Inflatable
Sea-to-Summit Ether Light XT Insulated Air3.217.34"Inflatable
Sea-to-Summit Ether Light XT Insulated Air Women's3.517.54"Inflatable
Sea-to-Summit Ultralight Insulated Air Women's3.515.82"Inflatable
Sea-to-Summit Ultralight Insulated Air3.116.92"Inflatable
Sea-to-Summit Comfort Light Insulated Women's3.823.52"Inflatable
Sea-to-Summit Comfort Light Insulated Air3.721.92"Inflatable
Sea-to-Summit Comfort Plus Insulated Air429.82.5"Inflatable
Sea-to-Summit Comfort Plus XT Insulated Air4.741.83"Inflatable
Sea-to-Summit Comfort Deluxe SI6.5704"Self-Inflating
Sea-to-Summit Comfort Plus SI4.1343.125"Self-Inflating
Sea-to-Summit Comfort Plus Women's SI5.133.53.125"Self-Inflating
Sea-to-Summit Ultralight SI2.6191"Self-Inflating
Sea-to-Summit Ultralight Women's SI2.919.21"Self-Inflating
Sea-to-Summit Comfort Light SI3.1232"Self-Inflating
Sea-to-Summit Comfort Light Women's SI3.823.52"Self-Inflating
Sea-to-Summit Camp SI4.2271.5"Self-Inflating
Big Agnes Insulated Q-Core SLX3.2183.5"Inflatable
Big Agnes Insulated Q Core Deluxe4.3253.5"Inflatable
Big Agnes Insulated AXL Air3143.25"Inflatable
Big Agnes Insulated AXL Trail Boss4.4403.25"Inflatable
Big Agnes Insulated Air Core Ultra4.5223.25"Inflatable
Big Agnes Air Core Ultra1.4183.25"Inflatable
Big Agnes Insulated SLX Tent Floor3.2433.5"Inflatable
Big Agnes Third Degree Foam1.5120.5"Foam
Big Agnes Hinman5341.5"Self-Inflating
Big Agnes Two Track3.3212"Self-Inflating
Big Agnes Twistercane BioFoam Pad1.7140.5"Foam
REI Trailbreak SI5.1401.75"Self-Inflating
REI Trailbreak SI Women's5.3371.75"Self-Inflating
REI Kindercamp4.5291.5"Self-Inflating
REI Camp Bed SI7.6582.5"Self-Inflating
REI Camp Dreamer XL SI6.61024"Self-Inflating
REI Camp Dreamer Double SI6.61494"Self-Inflating
REI Flash Thermal4.7192"Inflatable
REI Flash 3-Season3.2162"Inflatable
REI AirRail Plus3.3251.5"Self-Inflating
REI Air Rail Plus Women's3.7251.5"Self-Inflating
REI Stratus Insulated2.9212.5"Inflatable
REI Kindercamp2.5191"Self-Inflating
REI Camp Dreamerr2.7544"Inflatable
Exped FlexMat1.510.60.7"Foam
Exped FlexMat Plus2.217.61.5"Foam
Exped DownMat XP 97.831.23.5"Inflatable
Exped DownMat UL Winter7.122.23.5"Inflatable
Exped SynMat UL Winter5.2213.5"Inflatable
Exped SynMat HL Duo Winter5372.8"Inflatable
Exped SynMat UL2.914.32.8"Inflatable
Exped SynMat HL2.912.92.8"Inflatable
Exped SynMat HL Duo2.929.32.8"Inflatable
Exped SynMat UL Lite2.313.42"Inflatable
Exped AirMat UL Lite1.312.32"Inflatable
Exped AirMat HL1.310.92.8"Inflatable
Exped SIM UL 3.83.130.71.5"Self-Inflating
Exped DownMat XP 75.828.42.8"Inflatable
Exped SynMat 95.232.23.5"Inflatable
Exped SynMat XP 95.228.93.5"Inflatable
Exped SynMat XP 74.8282.8"Inflatable
Exped SynMat 3-D 74.828.72.8"Inflatable
Exped SynMat Duo4.849.42.8"Inflatable
Exped DownMat Lite 53.821.92"Inflatable
Exped SynMat Lite 53.422.22"Inflatable
Exped AirMat Lite 51.318.52"Inflatable
Exped AirMat Lite Plus 51.319.82"Inflatable
Exped SIM 3.84.630.71.5"Self-Inflating
Exped SIM 56.1362"Self-Inflating
Exped SIM Lite 3.83.125.71.5"Self-Inflating
Exped SIM Comfort 54.330.52"Self-Inflating
Exped SIM Comfort Duo 54.381.12"Self-Inflating
Exped SIM Comfort 7.56.464.23"Self-Inflating
Exped SIM Comfort Duo 7.56.4117.13"Self-Inflating
Exped SIM Comfort 108.175.83.9"Self-Inflating
Exped MegaMat Lite 125.239.94.7"Inflatable
Exped MegaMat 108.1603.9"Self-Inflating
Exped MegaMat Max 1510.61226"Self-Inflating
Exped MegaMat Max Duo 1510.62086"Self-Inflating
Exped MegaMat Duo 108.11203.9"Self-Inflating
Exped DeepSleep Mat 7.58.5583"Inflatable
Exped DeepSleep Mat Duo 7.58.51163"Inflatable
Exped MultiMat Uno1.410.1.1"Foam
Exped Doublemat Evazote1.19.20.2"Foam
Klymaloft Sleeping Pad2.138.52.5"Inflatable
Mountain Equipment Aerostat Down 7.0519.42.8"Inflatable

Status of Industry Adoption

The adoption of the new R-Value standard was driven by REI, which requires that the sleeping pads listed for sale on its main website have an ASTM F3340-18 R-Value rating. However, that’s not the case with sleeping pads listed in the REI OutLet or REI Used Gear sections of their website.

Many sleeping pad companies have still not adopted the new ASTM F3340-18 sleeping pad R-Value standard and it’s not clear that they ever will. In fact, many manufacturers don’t test their pads at all, but “estimate” the R-values of their sleeping mats and pads. In the absence of a standard definition and test procedure,  it’s hard to tell if their estimates are accurate or whether they’re comparable to those produced by the standard ASTM F3340-18 R-value testing protocol.

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50 comments

  1. Interesting. The table suggest that an Xlite is perfectly adequate for most people down to at least freezing, with an Xtherm only needed when it gets bitterly cold, down towards zero F.

    • Yep. But as noted, women and cold sleepers should add +1 since they’re generally smaller in stature and generate less body heat. The women’s Xlite is a good value.

  2. Wow! This is a wonderful table and with the ability to sort too! It must have been a fair amount of work to put together. Thanks Philip!

  3. Is there any drawback to using a high R-value pad year round? Seems to me that, balancing out the weight of the pad, one should buy the pad with the highest R value their budget allows for. Great resource – thanks for publishing!

    • No – there’s no reason not to use a high R-value pad all year round. What do you think all those car campers are doing with their R=10 pads. :-)

      • Some disagree. I have no personal experience, but I have heard a number of people claim they found using a warm pad like the X-Therm in the summer can be too warm to be comfortable. I suspect it depends on conditions in the location, your particular tolerance and how hot you sleep in general.

      • I find it hard to believe that people are sleeping too warm due to their pad. A bedroom memory foam matress has an R value of ~4-6/in. If it were the case that an Xtherm pad is too warm, no one would be comfortable in their bedroom at home. Temperature regulation is done on top.

      • It struck me as an ill-formed and unsubstantiated remark as well. Furthermore, pads prevent heat loss. They don’t “make” you warmer. It’s a common misconception on how they function in a sleep system.

      • How is it “ill formed” to report “what a number of people claim” qualifying it with “I have no personal experience”? I did not suggest it was proven fact…although how people feel is subjective in anycase. It seems to me ill informed to assume a warm pad is always better regardless of circumstance. Here’s a theory for you…Insulated sleeping pads retain and reflect your emitted body heat…that is how they work. If the ambient air is hot, still and humid having your body heat reflected and radiated back at you is not necessarily a useful thing. You want to be cooler not hotter. You don’t uses a 0 degree sleeping bag when it is 100F because it retains too much heat. It follows that the same is true for a 0 degree pad. To put it another way the ground can be cooler at night than the air and will act as a heat sink which will help cool you off. It seems quite likely in such circumstances you may be more comfortable with a less insulated pad. You still want a pad because the ground is hard.

      • It’s ill-formed because you don’t cite your source, what pads they used, locale, temperatures, or anything else of substance to help a reader determine whether it’s a significant observation.

      • Phil, regarding your observation that sleeping pads prevent heat loss but don’t make you warmer, isn’t that true of a sleeping bag? Of anything that insulates us from the external temperature? So no, no insulator “warms you up”, but in retaining heat, the insulator can certainly allow you to get too warm. Although I use the same ultralight high R value pad year round its rare that I’d want to employ the lower temperature of the earth to cool me down, so just shed clothing and top coverings. I like the comfort of the thicker pad, but there is a small price to pay in weight. It is not clear to me that OldGuyOut’s comment is wholly without factual basis, but I do agree that it is generally insignificant.

      • Consider the following: “Heat rises.” I don’t think people heat their sleeping pads, which they lie on top of. I don’t know about you, but my sleeping pads aren’t warm to the touch when I lie on them, even for a long time. They simply block the transmission of cold from the ground. So having a pad that can do that for lower temperatures (with a higher R-value) does not mean that you will be warmer.

        A sleeping bag is different because it traps the heat that you generate and prevents it from escaping, “up”. It can only do this up to its temperature rating, however (minus individual differences, of course).

      • Philip…neither did you. You just stated an assumption which I have illustrated could well be false. You did not qualify it with “in New Hampshire” or even “where I have camped”. You just illustrated your assumption with an unqualified statement about some random car campers.

        I said “like the X-therm” and “in summer” which seems specific enough for casting doubt on a dubious assumption.

      • You have to admit, it sounded like you heard it on Facebook or some other credible venue like that.

      • Phil, regarding how sleeping pads insulate. What you are saying sounds inconsistent. Are you saying that a sleeping bag traps air, but a sleeping pad simply prevents cold transmission? Does a sleeping bag trap the air you warm up by radiating heat into it? Does a sleeping bag just block the transmission of cold air to your body? I think the principle is the same Phil. Both insulators trap heat you radiate. Yes, my pad does feel warmer than the ground its laying on and that heat had to come from somewhere. The inside of my sleeping bag, likewise, is warmer than the outside. Regardless of the insulator, a body is always generating heat through the metabolic process. If the heat cannot be radiated away then you will overheat. If it can’t generate enough metabolic heat to keep the body warm then you need insulators to trap the heat. That’s what the dead air in an insulator does.

      • I think it’s just a matter of degree. While some radiation does enter the pad through the surface you lie on, it’s offset by the coldness of the ground so that it is not heating you as much as keeping the cold from chilling you. Of course I could be wrong. Its happened before, as my wife is quick to point out.

      • Amateur thermodynamics aside, the point is “some people”. It may not bother you to sleep on an over insulated pad in the summer but it does not follow that everyone is the same. The downsides of carrying a high R (winter) pad for 3 season are 1. they are typically heavier than you need, 2. they are typically more expensive for the same basic pad design and 3. since they over insulate you may find they feel too warm in some conditions.

        I would say if you rarely camp in cold conditions you will probably be better off just added an inexpensive foam pad to your moderate R three season pad for the one or two times you do. For winter you need to aim for the combination having an R of >5. Fex. adding a Z-lite to an X-lite gives you R 6.4 @ 26oz..not as good as an X-Therm but still competitive with other pads and a more flexible setup since you have a day pad.

      • Never did I consider that what I thought would be a pretty straightforward question would cause me to revisit my thermodynamics classes which FWIW were several decades ago.

        Heat flows out, not cold flowing in. The energy/heat your body produces wants to flow to a lower energy state. Insulation prevents that from easily/quickly happening. Heat rises so from a heat retention standpoint the bag (or blanket) on top is more critical. Heat can be drawn more quickly from a solid/liquid than from a gas (why you’ll go hypothermic in 32 degree water much faster than air). The pad puts a layer of air (and reflective/insulation) between you and the ground. What would be ideal is if you could have a pad that’s filled with a vacuum – noodle on that.

        Old Guyot – you’re right, a winter pad will be heavier and cost more (though I could argue both are nominal differences).

        If someone has what is their normal “summer sleep system” that includes a low R pad and then they swap in a high R pad – sure, maybe it makes them sleep warmer than they’re used to. But that should allow for a lighter weight bag (offsetting weight and cost).

        I strongly doubt someone is laying, bagless, on the high R pad going “this thing is causing me to be too warm”.

      • Wow, what a great conversation! As we all know, there are 3 kinds of heat loss.
        1) Radiant
        2) Conductive
        3) Convective

        I think we need to point at specifics in the above conversation.
        Radiant heat loss is what makes the thermal layers effective in preventing heat loss. The x-therms use this technology
        Conductive heat loss happens when you lay on the cold ground. Anything that comes between you and the prevents conductive heat loss.
        Convective heat loss is prevented by an insulator. Air, down, synthetic ect…
        A Sea to Summit Ultr light Insulated addresses all 3 of the heat losses. Its got a single layer of the radient film, An inch of Thermolite and and Inch of just air.
        A Thermarest Prolite deals with convective and conductive heat loss.
        I think its pretty weird to think that an insulated pad in the summer is not going to sleep any warmer than a non insulated pad. The convective heat loss prevention in a sleeping bag is the same as the convective heat loss prevention in a pad.
        Of course I could be wrong.

      • I think this discussion is missing a piece of real-world information that’s important to consider.
        When you lie on a sleeping pad, your body and sleep insulation doesn’t cover the entire top surface or sides of the pad.
        If your body heat is heating the pad, it’s also radiating a lot of that heat back out.
        That’s why it doesn’t surprise me that you wouldn’t feel *noticeably* warmer on an insulated pad in summer.

      • I would agree that excess heat does escape from the pad. Can you please be specific in what pad you are talking about and we can bring in the efficiency of how that pad disperses heat? I think my remark further down the page deals with this in a very practical way. The last one with “John” on it
        “radiating a lot of heat” is a very general statement that needs some clarification.
        Thanks!

      • I was sleeping on an XTherm when I realized this. But it would be the same if I was on an XLite or foam ZLite.

      • Very good. I have slept on both the Xtherm and zlite. The xtherm is also where i’ve noticed “a lot of heat loss” So I agree with your statement 100% on that pad. There is no insulation that would prevent the circulation of air and thus a high degree heat loss. That is a huge problem with a radiant barrier pad.
        The xtherm is a 3 layer radiant heat film pad. The Xlite is a 2 layer radiant heat film pad so would work on the same premise.
        The zlite and ridgerest are my go to pads. I have used these extensively. Once they are warmed up they retain the heat much longer than a radiant system. So I do not believe the foam pads lose heat at nearly the rate as the above. But I belive a better comparison would be the xped down 9 pad.
        In my experience, the heat lose dose not allow for cold air to recycle underneith me. Thus a better retainer of heat.

      • I find my X therm is too warm in the summer. I literally sweat where my skin is on the pad. I drop down to a lower r value pad in the summer due to this issue. I have had low and high r value pads on the same trip and I can tell you the high r value will retain too much of your body heat on those nights that don’t get below the mid 50s. I’ve used the X therm below zero many times and it performs well.

    • Yes. Get the highest r value pad as long as its not too heavy. I have a xlite, xtherm, tensor insulated and dumped the uberlite after a very cold night on the pct. Tensor most comfy but cold, xtherm for all shoulder season and xlite for summer. But I’m a string bean.

  4. Any chance you could add two more columns? How many people does it sleep? R-Value divided by weight?

  5. We’re having record cold down here in Texas and I decided to use this as an opportunity to do some highly unscientific and very subjective tests of my winter sleeping pads and camping system. I set up a tarp in my backyard as shelter and put a scrap piece of Tyvek on the snow as a ground sheet. I used a Lucid Moonstone 800 20°F down bag, wore synthetic long johns under my pants and shirt and Darn Tough merino wool socks. I do sleep a bit warm so my results are… well… my results.

    The night before last, it got down to 5°F (-15°C). I used a Sea to Summit Ether Light XT Insulated Air pad (R 3.2) but after a while, could feel the cold from below. I put a Nemo Switchback UL (R 2) under it and it helped but was still cool, borderline uncomfortable but manageable. I slept until 8am when ‘bladder chatter’ sent me into the house.

    Last night, it got down to 0°F (-18°C). This time, I used a Therm-a-Rest NeoAir X Lite (R 4.2) on top of the Nemo Switchback (R 2). I was plenty warm all night and slept comfortably until 7am when my body suggested a flatter bladder is a gladder bladder and I retreated to the casa.

    The dog slept inside the last couple nights because we wouldn’t send a dog out on nights like that!

    I wanted to test my Woman’s Therm-a-Rest NeoAir last night but couldn’t find it in my camping gear. Women’s sleeping pads often are lighter and have a higher R rating. They usually are 66″ (1.67M) length but they work for me since I’m only a couple inches taller than that.

    Tonight will be about 21°F (-6°C)–hardly worth sleeping outside!

    A couple years ago, I tested a Klymit Static V Ultra Light Insulated Sleeping pad and found the comfort range for me for that pad was about 25°F. My older Big Agness Insulated Air Core (different model than sold today) had a personal comfort range about the same.

    • My wife asked me just today…when are you going on your next 3 day trip? Temps in the single digits here at night….

      • You’ve been warmer than us for several days.

      • And a seemingly endless stream of storms that keep piling on more snow.

      • It got down to 12ºF (-11ºC) last night, so… it was time for another test! Perhaps I should have tried the night before at 11ºF (-12ºC).

        I wanted to see my personal comfort range for the Sea to Summit Ether Light XT and the NeoAir X Lite on the groundsheet without the Nemo Switchback under them.

        I started with the Ether Light XT (R 3.2) but at 3am decided too much cold was coming from below and switched to the NeoAir X Lite (R 4.2). It did OK but I was still a bit cool.

        My testing says for me, R 3.2 is comfortable to about 18-20ºF (-7 to -8ºC), R 4.2 is comfortable to 13-15ºF (-9 to -11ºC), R 5.2 will get me to 7-8ºF (-13 to -14ºC) and R 6.2 easily got me to 0ºF (-18ºC). I would be able to sleep about 5ºF (2ºC) cooler than what I’ve got listed as my comfort range–I’d just be somewhat cold but I’d still manage. For future trip planning purposes, I’ll stick with my comfort range estimates.

        The testing was fun and probably served to reinforce the feelings of many that Grandpa is somewhat ‘teched in the head’. The weather is finally warming up and the low tonight will be just a few degrees below freezing–not worthy of a test. I’ll dry the tarp in the sun and pack it up until the next blizzard.

  6. Pls use also the metric system for weight and thickness. And what is wrong with the copy&paste functionality in your page?

    • We protect our content from theft since so many people steal our hard work and republish it on their own website without permission. Copying and pasting is a violation of our terms of service and international copyright law.

      It’s still free to use though for readers from our website.

      • Ah – thanks for the info… I can understand this… I only tried to copy the title and some teaser text to share it…

  7. Thank you for this, Phillip.
    That’s very handy to have all this data in one place, for certain!

  8. I have used Thermarest self-inflating mattresses since 1980 with great success.

    Now I use 2 REI FLASH air mattresses:
    REI FLASH Insulsated 3 season -> R 3.2
    REI FLASH All Season-> R 5.3 (replaced by REI FLASH Thermal, R 4.7)

    I now prefer those air mattresses to self-inflating mattresses.

  9. Thank you, your articles are informative and inspiring. I’m European so I read all your data with calculator in my hand to understand the figures. ? I wonder if there would be a chance to put metrics, it would help us significantly on this side of the world.

    • Suggest you look up tge weights by clicking on the links. The actual weight in grams cant be calculated exectly because you lose precision in the conversion.

  10. The standard testing for “R” values is a great starting point. All pads are tested in a laboratory setting with no variation. In real world situations, I have found
    Pads with radiant heat shields, but with no other insulation, tend to lose the built up heat when you toss and
    turn in your bag. The colder air from the side and bottom tend to move more freely underneith you and you
    need to reheat that air. If you toss and turn a lot like me, you can feel this. A radiant barrier pad with an
    insulation retains that heated air much better.

  11. I use the x-therm all year around. I suppose I am just too old/lazy to change but I am happy to carry a few more ounces for something that has proven to work well over time. In my defense, the heavier x-therm uses a fairly tough material. Ultralight usually gets that way by using lighter-weight material so there may be some trade-off in durability. Mainly just an excuse for a habit

  12. I’m curious to know whether there has been any more news from Klymit re. their updated R-values? It’s been roughly a year since they retracted their previous numbers and said they’d be rolling out the correct numbers over the next year. I have yet to see any new numbers other than the one you provided above!

    • No news.

      • Thanks for the quick reply. I’ve just emailed Klymit….maybe I’ll strike gold and get some info from them. It’s so frustrating not having accurate information for their pads!

    • Just heard back from Klymit!

      I asked them about the Insulated Static V and the Insulated Static Luxe SL.

      According to the representative who replied to my email, the Insulated Static V has been tested and received a result of 1.9 on the ASTM scale. The Insulated Static Luxe SL has not yet been tested.

      • I purchased a Klymit insulated earlier this year and was wondering why it felt colder than expected when I slept on it for 3 nights. I am currently in the process of returning it to the seller as this has the potential to be a serious safety implication and I am glad I tried out the mat before needing to rely on it to keep me warm.

      • Those Klymit pads depend on the loft of your bag to fill in the gaps between the ribs of the pad to insulate you. As a quilt user, I’ve found them nearly useless. That low R value doesn’t shock me at all.

  13. I do agree with this comment. The R value of foam pads appear very low compared to how they feel in practice. I have used an 10mm or 11mm closed cell foam pad (cheap $10 pad) on many snow trips. The temperature I would estimate to be minimum of -5. I have had no issues at all and I did not feel the cold at all – perhaps it started to feel it marginally if you put your mind to it – but not enough to make any difference to sleeping comfort. The R value for such foam pads would suggest that even a pad like the uberlite would be too cold for these temperatures, yet the R value is about double that of such foam pads.

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