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 | 43 | 36 | 29 | 22 | 15 | 8 | 0 | -7 | -14 | -21 | -30 |
| Minimum R-Value | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 |
| Air Temperature (C): | 10 | 6 | 2 | -2 | -6 | -9 | -13 | -18 | -22 | -26 | -30 | -34 |
| Minimum R-Value | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 |
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 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 2022?
- Klymit finally got around to testing most of their sleeping pads using the new ASTM 3340-18 sleeping pad R-value standard. Their pads’ new R-values are generally much lower than the previous rating they had published before the standard was adopted.
- Exped got rid of a lot of their older sleeping pads. They still have a huge product line, but it’s a little more focused.
- Sea-to-Summit also added a few new pads and increased the number of sizes they offer. They still offer the thickest 4″ air pads suitable for lightweight backpacking.
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.
I am fairly thin and sleep cold. My winter bag is the women’s Feathered Friends Murre EX, which does a pretty good job keeping me warm. However, when I switched one of my pads to the Exped Downmat XP 9, I felt positively toasty! It is totally worth the extra weight.
That would do it!
Thank you for researching this. I sleep warm so the chart has to be shifted to notch or two for me, however the listings of some of the pads I’ve tried correlate very closely with my experience. I found the Kyymit Insulated Static V to only be good down into the mid-to-upper 20sF for me. Now I see why. It’s only R 1.9. I slept just fine in – 7F using a Therm-a-Rest NeoAir XLite Women’s (R 5. 4).
I have a few Klymit pads and I was pretty disappointed to see these ratings. Maybe there is something to their claim about air pockets in the folds, though. I have been pretty comfortable sleeping on snow with only polycro under the pad. I even had a good night’s sleep on the x-frame on the snow, but I was in the middle in a 3 person tent. Granted, temps probably never dropped below 20 deg. Now that it’s in my head, I’ll probably be colder.
There’s nothing different about the pads; they’re just compared to the competition using the same test, for a change.
Just note, that they can’t test the R-value of the pads that have holes in them. Just falls out of the standard “tent.”
Seems to me that the weight “penalty” to go with a super warm pad people would be better served with a mid-R value pad and add in a foam pad underneath when necessary. So many options though, which is great.
Now I see why the Women’s Xlite is so popular. Amazingly good insulation value from a quality brand, yet only 12 oz.
Mine was definitely a good choice.
I’m a 5′ 7″ guy. The NeoAir Xlite Women’s @ $127.50 on sale is easily my best piece of gear for all the reasons we care about.
I gather Gossamer Gear hasn’t tested their foam pads.
God no. Love those guys but I doubt they ever will.
The r-value testing procedure does not account for cold air at the sides of the pad, and whether that cold air cools the air inside the pad. If the sides of an inflatable pad are exposed to frigid air, you can expect it to feel less warm than it’s r-value would predict. Or, conversely, you can expect foam pads to do better in the field than you would expect, based on their r-value, relative to the inflatables. Self-inflating is a mixed bag. The important variable is how much air can mix inside the pad. A narrower pad could actually end up warmer if the pad is protected by the draped insulation of the quilt/bag. Another consideration would be to put foam on top of an inflatable.
Hmm true but I think the most important weakness in r value testing is air movement inside the pad. With StS pads there’s more air movement than in the Xlite. So if someone moves a lot during the night cold air from the bottom mixes with the warm one from the top. So r value is a static measure. But that’s just an opinion I’ve heard, I do’t own those pads.
Pointless theorizing and rumors. I find it humorous, no amazing, at the armchair theorizing that people come up with to justify their gear purchases.
DariusPL, agree with you. The standard R value test is in a lab with no variables such as movement. A neo air with 3 layers of reflective heat shield with an R value of 5 is the same as an Exped down filled pad with an R value of 5 with no movement.
When you turn from side to side or whatever, the warm are stays in place with the down filled pad as opposed to the heat shield pad. So in the field, an insulated pad is more effective.
Of course it weighs more.
Of course StS states quite the opposite on their site “Loss of warmth in a mat is compounded massively by air being ‘pumped around’ inside the mat when you move. In mats with large, ‘cushy’ chambers you squeeze the warm air from beneath your torso off to the extremities of the mat. Here it dissipates and you get cold. Stable, baffled constructions are much better than large tubes because they reduce the amount of air being moved. Air Sprung Cells™ are better still: press down on one cell and the amount of air which moves is very, very small. Your weight is spread over many cells which virtually eliminates internal air movement.”
Mordicia, also agree with you. See my lower post
In 2022 a popular Nemo tensor getting an upgrade in R Value:
https://gearjunkie.com/camping/nemo-tensor-sleeping-pad-review-2022
That’s just a press release regurgitated. You can’t actually buy the new pad anywhere including from NEMO.
You have to understand the “Gear Junkie” business model. They’re in bed with the manufacturers to create a buzz.
I love those guys, but I discount all of their “reviews”. Too bad, they used to be credible in the old days. But as soon as you hire salespeople to sell ad inventory, it corrupts the editorial.
I might add, I’ve had the new pad for the past few months, but haven’t reviewed it because I was respecting NEMO’s press embargo where they ask us to hold off writing about new products until they become commercially available. Either Gear Junkie ignored that or they were paid to write that article. I don’t much care. I don’t accept advertising like that – seems kind of tainted if you know what I mean. In the meantime, you can expect the old pad to go on sale at all major retailers. Good time to grab it up cheap.
I find it shameful that Klymit still publishes their old r-values right next to, and before the new values.
I don’t know if its shameful, but it’s certainly embarrassing!
A cheap Z-pad hack if you are a “once a winter” camper: turn a mylar emergency blanket into a long tube with double sided tape. Slide it over your z-pad to trap air. There will be a lot of crinkling noise but it might help your kid or Scout get through their overnight winter camping trip
Ha! good idea to turn my cheapo ultralight decathlon forclaz m100 pad/ass pad/frame into “almost 3 season” pad ;)
I have both the REI FLASH 3 Season and the FLASH Thermal mattresses. They both are light, pack small and inflate with the Sea to Summit inflator/dry sack.
BUT, REI hd a rash of FLASH mattress failures at first. I fervently hope this has been corrected by the time I got my mattresses. REI customer service assures me they will replace any mattress that fails at the weld seams.
I do like that Sea to Summit now has tougher fabric on their air mattresses and feel StS is the leader in the insulated air mattress field. As well they have the best inflation bags and valve system, SHICH REI borrowed, to their credit.
Despite sleeping cold, tucking my ee Enigma quilt below the side edges of my Uberlite–and wearing all layers–makes it comfortable to freezing in a shelter/tent. Without tucking, it’s too cold.
Also, thanks for the analysis, chart, and ethics!
Thank you for the detailed chart! This article was most helpful. Though I won’t pursue winter camping this year, these are golden tid bits of info that I gather for future gear, uh, “enhancements…” Please keep this article archived.
I refresh it every year. You can usually find it linked on the home page. I was a big advocate of standardized R-values and was in touch with many of the committee members when the standards were formulated. I think the standard makes it a lot easier to compare pads from different manufacturers and helps cut through a lot of the marketing BS that brands put out there.
Why do latest thermarest xtherm and xlite pads go flat overnight? It’s a pandemic. What gives?
Unless I’m reading things wrong, according to the Therm-a-rest web site the X-Lite reg and X-lite wmns weigh 12.5oz the X-Therm reg weighs 17oz and the X-Therm max reg weighs 19oz, not 12, 15 and 17 as you have above?
They must have *just* updated those specs because I updated this table very recently.