SectionHiker.com Backpacking Gear Reviews and FAQs 
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): | 50 | 30 | 25 | 10 | 0 | -15 | -25 | -40 |
| Minimum R-Value | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| Air Temperature (C): | 10 | -1 | -4 | -12 | -18 | -26 | -32 | -40 |
| Minimum R-Value | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
In addition:
- R-values are additive, so you can combine two pads to increase your warmth level. For example, it’s common to carry a foam sleeping pad (usually R=2) in winter to use as a sit pad when eating and melting snow that you can place under an inflatable pad to increase their combined R-value for sleeping.
- 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.
- If a pad model has multiple sizes, they all have the same R-value unless specified otherwise
- EN sleeping bag temperature ratings are predicated on using a sleeping pad with an R-value of 5 or higher. If you find yourself sleeping cold in temperatures where you’d expect your sleeping bag should keep you warm, it may be because your sleeping pad has an R-value less than 5.
Sleeping Pad R-Value Comparison
The following table provides a side-by-side comparison of the ASTM F3340-18 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.
Key: Air – Air Mattress, SI – Self Inflating, Foam – Closed Cell Foam
Sleeping Pad R-Value Standard
In 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
What’s New in Sleeping Pads in 2023?
- Thermarest has come out with a new NeoAir NXT generation of pads that are quieter, thicker, and have a slightly higher R-value than the last generation NeoAir pads. I don’t think the changes really warrant replacing your existing NeoAir pad though, but the changes should be attractive to new purchasers.
- Big Agnes has a handful of new lightweight pads that are 3+ season capable. They’re not widely available in retail yet, but they make good gear and might be an interesting alternative.
- Klymit continues to have an impenetrable product naming scheme. I don’t get it.
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.
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.
Updated December 22, 2023.
Wondering if self-inflating foam pads suffer from the same loss of insulating value as a sleeping bag when compressed by your body weight?
The R-value tests are done with a manikin so you should assume that that compression is baked into the R-value to some extent.
The test is performed using two metal plates, one on the top and one on the bottom of the pad. The top plate is 35 deg Celsius to mimic the temp of a persons body and the bottom plate is 5 deg Celsius to mimic the cold ground. The test measures the amount of energy used to keep the top plate at a constant 35 deg Celsius. The more energy used, the lower the R-value.
That might be how they test building insulation, but that’s not the procedures used for the Sleeping Bag standard.
You are correct. Compression of the plates and internal pad pressure are all standardized. ASTM F3340-18 has been replaced by ASTM F3340-20 (year 2020 v 2018).
https://cdn.standards.iteh.ai/samples/112900/775659741b374013a61d2927880be384/ASTM-F3340-22.pdf
Do you know if the BA Zoom UL is compatible with the Schnozzle?
It may well be since BA tends to use a flat valve like Exped’s. Patience!
I will be patiently waiting for your review on the BA Zoom pad!
I don’t know if it is truly a different pad than the current generation, but my Klymit Static V Insulated pad is way warmer for me than one of my other air pads with a higher R-Value.
I think it has something to do with the fact that it is 23 inches wide, not 20. It’s a bit thinner than the air core too, not as comfy to sit/kneel on, and a solid 6 oz heavier…. but I haven’t used the air core for a few years now. The Klymit is just warmer, a bit wider, and gives me a better night’s sleep.
(and I’ve used it at 20F at 10,000 feet; a pretty decent test IMO)
Very strange to me that Klymit is getting destroyed on this list every year since they went to the standard test. But you can’t argue numbers. ?
I just got the Klymit Static V Insulated, and on the packaging it has an R value of 4.4, the article above rates the R value as 1.9? Yet, they quote the the new ASTM F3340-18 sleeping pad R-Value standard value above. So how can they follow this standard, and put it on their packaging, yet this site only lists 1.9 as the R value. Wouldn’t this be false advertising on Klymit’s part, or is the article above to be taken with a grain of salt, and it’s on how you want to interpret the information above? If they are following the new standard, Klymit saying thier pad is over 2 times higher then what is said above, someone has to be wrong here?
I suspect they finally sent it out to be tested and updated the packaging after we published this R-value at the beginning of January of this year. Thanks for the heads up. We’ll go and update any other changes that Klymit has made.
Hi Philip,
Thanks very much for following up on my comment so quickly. My intention was not to question the article, but more to try and figure out if the Klymit pad I just bought yesterday was stating the correct R value, and the article above had me questioning that. I did buy it based on their claimed R value and really didn’t know a lot about ATSM (which they have on their packaging) until I google ATSM and your article came up. I just want to make sure that what I bought was /is as advertised. Hopefully you are correct, and they sent it out to be tested and validated by ATSM which I would imagine they would have in order to be able to claim that on their website and packaging.
Thanks,
Scott
I’m sure they wouldn’t claim it if it wasn’t true.
my Klymit V was higher rated at one time and seemed that it worked well all in all to about 25 degrees but I do think the waffle design probably allowed a measure of heat loss. it sure was easy to inflate though.
The ratings changed for some of Klymits pads when they tested them with the new R-value rating since it was a totally different test. I don’t personally like the Klymit pads and now that the company has been sold, they’re just going to stop innovating and sell existing product.
When is the new Thermarest neoair with R-value of 7.3 gonna be available do you know? I tried to buy it on their website but says sold-out.
thanks!
It was available last week – REI will probably be the first to get the next shipment when the next boat comes in.
Nemo just released their Tensor Extreme Conditions with an R-value of 8.5
I think they just published the press release.
Extreme is available for purchase now, all season with r5.4 out in 2024. Personally I am looking forward to reviews on all season model, might be xlite nxt killer with better comfort, slightly higher R value and similar weight.
I’ve been using the All-season model since early autumn. It’s good.
I’ve had a Thermarest NeoAir mattress for some years, and it has served me well. When I camp in the winter (it’s not often) I used to carry a basic closed cell mat with me to help keep the floor cold at bay, it worked well but never rolled up small. I now carry three sit-on closed cell mats with me and shove these under my NeoAir to provide cold protection to my torso. They work well, are easy to pack and they weigh next to nothing. I’ve often been tempted to buy the latest model of mattress but so far have kept to what I know and like.
Thanks for making this list. I am glad manufacturers are innovating but the sheer volume of choices is daunting. THis list lets us to “trim the herd” down to some choices that are appropriate to our particular use-case.
The Exlite at 10 degrees would be cold for me.
I have many nights on my old model and it’s one piece of gear I count on.
They do this tests I am assuming in a controlled environment where the wind and convection from the ground is different than a lean to In November.
I find an Extherm pushing it then.
I think the old values were more realistic.
Been winter backpacking since the early 80’s. Use a therm a rest z lite sol. Was tought at an early age to find some leaves or pine boughs for added insulation under a tent. It doesn’t take much of a separation layer to buy a lot more R. There’s so much dependence on products vs what can be found on the trail.
Cutting pine boughs is out of fashion ala Leave No Trace.
Regarding ASTM testing and R-values: While I’m glad that the industry is moving forward to try to standardized “warmth” ratings, the ratings might not reflect real world realities. (As even the test standard concedes in Section 1.1.) There are at least three subtleties not considered in current testing: 1) There is a psycho-temperature aspect to perceived warmth, akin to psychoacoutics in sound. In the same way that a chain saw sounds louder to the human ear than a softer sound at the same dB level, a piece of steel feels colder to the touch than a piece of wood at the same temperature. 2) Heat transfer caused by movement of the sleeper. A sleeping pad might have a very high R-value when tested statically by machine, which is the best case for the pad. But the test doesn’t measure R-value dynamically, as when the sleeper moves around, changing reflectors or stirring up air, moving cold air at the bottom of the pad with warmer air at the top. 3) Similarly, the test does not take into consideration the curves/density changes of the human body. The test uses a flat plate which compresses the pad uniformly and somewhat linearly. This is wholly inadequate to measure for side-sleepers. And it’s not even adequate for those who sleep on their backs, the backside of the human body is not flat. It would be better if the test used a metallic mannequin that mimicked the protuberances and density changes of the (average backpacker;s) body, and measured on back, side, and front.
You bring up good points but no test (for anything) is able to take into account all variables. Even your suggestion on the protuberances – well, some of us might have more “natural insulation” in some of those bumps than other people.
I find the R numbers a good starting point for comparison to one another. All else equal no one is going to feel the difference between a 4.2 and a 4.5 but a 3.0 should GENERALLY be quite a bit better than the 1.3. More extensive testing is going to add cost to the product and IMO they need to balance that out that cost with the value of the information it might provide to the consumer.
The testing/rating doesn’t remove all trial and error but just like MPG ratings for your car it gives good relative measures. The key being YMMV.