From 2020 onwards a new ASTM F3340-18 standard for camping sleeping pads ratings, known as R-value, will be used by some leading brands in the sleeping pads industry. Read more below.
First, what is a sleeping pad R-value
The letter R is used for the word ‘resistance’. So this is a metric used to describe the efficiency of your sleeping pad to prevent heat loss to the ground. In general, the higher the R-value, the more thermally resistant the pad is.
The body heat is lost far more to the cold ground than to the air. This depends on various factors and it can be up to 50 times or so more. This is why sleeping off the ground, on a camping cot, can be a good idea. But it is true also that the ground can be warmer than the air. In this case the pad insulates you and allows you to stay cooler.
So, is this new ASTM F3340-18 Standard R-Value a compulsory industry standard
The answer is no, it is not. But a number of industry leaders will use this new ASTM rating and it will be easier to compare pads. These brands include Therm-a-Rest, Sea-to-Summit, Exped, Big Agnes, and probably a few more.
Some will use their own metrics, so this is just to know what you can expect. Hopefully, more and more brands will introduce this new standard.
How do they measure these ASTM R-values
They use hot and cold plates on the two sides of the pad and then measure the energy needed to keep the hot one at a constant temperature. There is some prescribed pressure in the sleeping pad, the hot pad is set to 95 F (35 C) to mimic the body and its temperature, and a few more details, you will see more in the video below.
They all claim that they have already used the same method before in determining the previous R-values, but it appears that there are differences in the old and new numbers. See some details here:
Are there big changes in the rating
As you know, some brands have never used R-values for their pads. This holds in particular for Big Agnes. So you cannot make an exact comparison.
But the good news is that this same brand (Big Agnes) is now using R-value instead of their previous temperature rating. I checked their Big Agnes Hinman Sleeping Pad on Amazon and it is with temperature rating. But on their site it is given with the new rating, see how it looks:
Just to know this pad was previously with the temperature rating -5 F. My earlier estimate was that this corresponded to the R-value 6-7, so I was not particularly correct.
Something similar is happening with Nemo’s sleeping pads. Earlier, they were with temperature rating, but on their site they now use both R-value and the temperature rating. I checked for their NEMO Roamer Self-Inflating Sleeping Pad. It is on Amazon with the temperature rating -30 F (-34 C). But on Nemo’s site it is now with R-value 6.
An interesting situation is with the Therm-a-Rest MondoKing 3D sleeping pad. The old R-value was 11.4 and this is still available on Amazon. But now on their site they have two versions of this pad. The new pad has ASTM F3340-18 Standard R-value 7. However, the big difference in this case is not necessarily due to the new rating scale. The weight difference in the two bags is significant. They do not provide numbers about the insulation weight alone for two cases, so it is far from clear what causes such R-value differences.
Take one more example, the well-known Therm-a-Rest BaseCamp Self-Inflating Sleeping Pad. Its old R-value was/is 5.8 and it is on Amazon where you can see a statement about R-value 5. But on Therm-a-Rest site its new ASTM F3340-18 Standard R-value is now 6. Not such a big deal in any case.
I have made some random checks around, and my overall impression is that the changes in ratings are not substantial. There are very few exceptions. Sometimes the new ASTM F3340-18 Standard R-value is bigger and sometimes it is lower than the old R-value.
Exped’s sleeping pads new R-values
I have contacted Exped and their Isabell Kohler from Customer Service was kind to send me the table which I give below. If you have some of them, you might want to compare with the new R-values:
Name |
2020: ASTM F3340 R-Value
|
FlexMat XS |
1.5
|
FlexMat M |
1.5
|
FlexMat Plus XS |
2.2
|
FlexMat Plus M |
2.2
|
Sit Pad Flex |
1.5
|
DownMat XP 9 M |
7.8
|
DownMat XP 9 LW |
7.8
|
DownMat 9 M |
7.8
|
DownMat 9 LW |
7.8
|
DownMat UL Winter M |
7.1
|
DownMat UL Winter LW |
7.1
|
DownMat HL Winter M |
7.1
|
DownMat HL Winter MW |
7.1
|
DownMat HL Winter LW |
7.1
|
SynMat UL Winter M |
5.2
|
SynMat UL Winter LW |
5.2
|
SynMat HL Winter M |
5.2
|
SynMat HL Winter MW |
5.2
|
SynMat HL Winter LW |
5.2
|
SynMat HL Duo Winter M |
5.2
|
SynMat HL Duo Winter LW |
5.2
|
SynMat UL S |
2.9
|
SynMat UL M |
2.9
|
SynMat UL MW |
2.9
|
SynMat UL LW |
2.9
|
SynMat HL M |
2.9
|
SynMat HL MW |
2.9
|
SynMat HL LW |
2.9
|
SynMat HL Duo M |
2.9
|
SynMat HL Duo LW |
2.9
|
SynMat UL Lite M |
2.3
|
SynMat UL Lite LW |
2.3
|
AirMat UL Lite M |
1.3
|
AirMat UL Lite LW |
1.3
|
AirMat UL M |
1.3
|
AirMat UL LW |
1.3
|
AirMat HL M |
1.3
|
AirMat HL MW |
1.3
|
AirMat HL LW |
1.3
|
AirMat HL Duo M |
1.3
|
AirMat HL Duo LW |
1.3
|
SIM UL 3.8 M |
3.1
|
SIM UL 3.8 LW |
3.1
|
SIM UL 5 M |
4.0
|
SIM UL 5 LW |
4.0
|
DownMat 7 M |
5.8
|
DownMat 7 LW |
5.8
|
DownMat XP 7 M |
5.8
|
DownMat XP 7 LW |
5.8
|
SynMat 9 M |
5.2
|
SynMat 9 LW |
5.2
|
SynMat XP 9 M |
5.2
|
SynMat XP 9 LW |
5.2
|
MegaMat Lite 12 MW ruby red |
5.2
|
MegaMat Lite 12 LW ruby red |
5.2
|
MegaMat Lite 12 LXW ruby red |
5.2
|
SynMat 7 M |
4.8
|
SynMat 7 MW |
4.8
|
SynMat 7 LW |
4.8
|
SynMat XP 7 M |
4.8
|
SynMat XP 7 MW |
4.8
|
SynMat XP 7 LW |
4.8
|
SynMat 3-D 7 M |
4.8
|
SynMat 3-D 7 MW |
4.8
|
SynMat 3-D 7 LW |
4.8
|
SynMat Duo M |
4.8
|
SynMat Duo LW |
4.8
|
DownMat Lite 5 M |
3.8
|
DownMat Lite 5 LW |
3.8
|
SynMat Lite 5 M |
3.4
|
Synmat Lite 5 LW |
3.4
|
AirMat Lite 5 M |
1.3
|
AirMat Lite 5 LW |
1.3
|
AirMat Lite Plus 5 M |
1.3
|
AirMat Lite Plus 5 LW |
1.3
|
SIM 2.5 M terracotta |
2.8
|
SIM 3.8 M terracotta |
4.6
|
SIM 3.8 M black |
4.6
|
SIM 3.8 LW terracotta |
4.6
|
SIM 3.8 LW black |
4.6
|
SIM 5 M terracotta |
6.1
|
SIM 5 LW terracotta |
6.1
|
SIM Lite 3.8 M |
3.1
|
SIM Lite 3.8 LW |
3.1
|
SIM Comfort 5 M |
4.3
|
SIM Comfort 5 LW |
4.3
|
SIM Comfort Duo 5 |
4.3
|
SIM Comfort 7.5 LW |
6.1
|
SIM Comfort Duo 7.5 |
6.1
|
SIM Comfort 10 LW |
8.1
|
MegaMat 10 MW ruby red |
8.1
|
MegaMat 10 LW ruby red |
8.1
|
MegaMat 10 LXW ruby red |
8.1
|
MegaMat 10 MW green |
8.1
|
MegaMat 10 LW green |
8.1
|
MegaMat 10 LXW green |
8.1
|
MegaMat Max 15 LXW |
10.6
|
MegaMat Max Duo 15 LW+ |
10.6
|
MegaMat Duo 10 M ruby red |
8.1
|
MegaMat Duo 10 M green |
8.1
|
MegaMat Duo 10 LW+ ruby red |
8.1
|
MegaMat Duo 10 LW+ green |
8.1
|
DeepSleep Mat 7.5 M |
8.5
|
DeepSleep Mat 7.5 MW |
8.5
|
DeepSleep Mat 7.5 LW |
8.5
|
DeepSleep Mat 7.5 LXW |
8.5
|
DeepSleep Mat Duo 7.5 M |
8.5
|
DeepSleep Mat Duo 7.5 LW+ |
8.5
|
HyperSleep |
1.3
|
HyperSleep Winter |
2.0
|
Doublemat Evazote |
1.1
|
MultiMat Uno |
1.4
|
MultiMat Duo |
1.4
|
MultiMat Trio |
1.4
|
How exactly to choose the appropriate pad and its R-value
There is nothing exact here. So very roughly speaking you might go for these options:
- For summer camping: R-value up to 1 or 1.5.
- For 3-season camping: R-value in the range 1 or 1.5 – 3 or so.
- For cold weather camping: R-value in the range 3 – 4 or 5.
- Winter camping: R-value (well) above 5.
This is only if you want to save money, so you will not necessarily buy an expensive high R-value pad for summer camping. But see next…
Can you use a high R-value pad in summer
Yes, most definitely so. A pad is not a heater. Any high-R-value pad will do the job in summer, but not any low-R-value pad will be good for cold weather. So if you invest in a high R-value pad, you can use it in all seasons.
What will happen next
Not much really. You will continue using the pads which you have now, their resistance is the same, nothing is changed. It is the new scale that is tweaked and modified, so those manufacturers who accept the new standards will add new values to their new pads.
If you buy a new pad, you might see the usual R-value or new ASTM F3340-18 standard for R-value. So you will know what this means and this is all. See the example from the mentioned Therm-a-Rest MondoKing 3D sleeping pad:
It is interesting that, together with the ASTM symbol above, they also give the seasons for the best use of this pad. As you realize this is for all seasons. Remember what I mentioned above, you can use a high R-value pad in all seasons. This is what they are saying as well.
My guess is there will be sleeping pads at discount prices, I mean those with the old R-value stickers. So check around, you might get some great items at discount prices, and this all just because of the old sticker.
Currently, this all may look like a bit of a mess, but in the long run, this will help people to compare and to choose among various brands. What do you think? Please let us know, there is a comment box below. We add news texts regularly, so stay informed, bookmark the site and visit occasionally.
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