Pad R-Value Overkill?

[bowhunthard88]

Alrighty... This may be a subjective issue, but looking for input from those of you who may have first-hand experience with certain R-value inflatable sleeping pads. So at what point, or to what temp, does "X" R-value get you to within your comfort level? I'm between two different "extreme" R-value pads and trying to rationalize what the "maximum" R-value is that I require (in reality). So, give me your temp to which you've been comfortable, your pad, and the pad's R-value, please!

Does a 1.2 increase in R-value offset a 6oz penalty? Is that 1.2 increase even noticeable? LOL

I am NOT looking to layer anything underneath. I just want the pad by itself to provide what is needed...

 

[taskswap]

This is going to be a super-subjective thing, I suspect. I use a NeoAir XTherm NXT that's supposedly rated to R-7.3. I do use a 1/8" Thinlight (closed cell foam) which supposedly adds R-0.5, but I mostly I do this to reduce how much my pad slides around my tent and add a bit of puncture-protection, so I don't really do it for any layering benefit from an insulation standpoint.

This replaced my old Trekology UL80, which was supposedly R-2.5. Do I notice the difference? Yes. But it's not all sunshine and roses. The new pad is definitely louder/more "crinkly" than the old one, and as a light sleeper I find this bothers me a fair bit. I definitely wouldn't go back - combined with my 0F Enlightened Enigma Quilt, I can be comfortable to 0-10F or so. But overall while I think a higher R-value is worth it if you're making a significant jump, obsessing over it misses some other easy wins.

For instance, I also got a goose-down hood, down booties, and "brushtail possum" gloves, and believe those three things made a bigger difference overall, for way less money and equivalent carried-weight. I can't say enough good things about the booties. On trips under 4 days I'll throw a pair of toe warmers in each night and the booties hold in that heat. Once my feet are toasty, the rest of me is much warmer all night.

At this point I bet I could be comfortable down to -10 or even -20, and the main reason I don't is non-sleeping times: at that temp range I'm not comfortable around camp early mornings/evenings when it's not time to sleep, without bringing so much gear we're talking a different class (e.g. having a friend horse-pack me in with full winter gear and a hot tent, where the R-value doesn't matter any more.)

 

[Drenalin]

I've used a Thermarest XTherm (not the new NXT) down to the mid teens by itself and was comfortable with a quilt. I believe that pad was R-6.9

I've also used a Sea to Summit Ether Lite with a Seek Outside Matty down to the mid teens and froze my nuts off in a quilt. I believe those two combined are only about R-3.7

I believe the rule of thumb of R-4+ for 3 season use (so into fall) and R-5+ (to go into winter) is pretty accurate, at least for me. You didn't specifically ask about this, but I haven't found pads to be "too warm" for summer use, specifically the XTherm mentioned above.

 

[bowhunthard88]

I personally currently own too many pads (7, I think?) LMAO from ~R3 up to R7.3 (Thermarest NXT). I'm also a solid back sleeper with a tendency towards a deep sleep (so the noise is really a non-issue). I'm more-or-less trying to justify, or negate, the purchase of another pad at about R8.5 (6oz heavier than the NXT)...

 

[rideold]

I think it depends entirely on the person and the pad. I have a Sea to Summit self inflating that is rated at 4.1 and a Big Agnes Q-Core that is rated to 3.2..... I can only use the Q-Core with an ensolite pad on top. It just feels cold unless it is too warm for my sleeping bag. The Sea to Summit I've used down to 30 or so and never been cold even though the r value charts put the Q-core plus ensolite as warmer. Go figure right?

 

[Drenalin]

I'd be surprised if 8.5 is necessary, but you might find this chart helpful:

 

[bowhunthard88]

Based off the chart, I think I'd have a hard time justifying the weight penalty for temps that I'll never be camping in lol.

 

[Read1t48]

I use a NeoAir XTherm year round. Whether August archery or November rifle. Quilt can be buttoned down or opened up in early season. Tent, tipi, or tarp can be vented for airflow. At base camp, you can add a blanket under or over system. When back packing I also supplement with down jacket and booties and beany in real low temps. Versatile system. Buy one and be done.
I think a pad is the most important component in a sleep system. I would rather have a really great insulated pad and the world’s worst sleeping bag rather than the other way around.

 

[LionHead]

Another Xtherm user, had the original and now the NXT. I use it for all season all the time with and EE convert in 0 degree.

Theyre expensive but weight, r value and durability aren't matched by much else in the industry. Just get the xtherm and don't think about R value again.

I had an old Xtherm that had a slow leak and they fixed it up for me for $20

I'll add a CCF pad for puncture resistance or comfort if in a base camp but sleeping arrangements don't change unless it's summer hammock time

Good luck on your search.

 

[Dos Perros]

R-value is a measure of thermal resistance. The math kinda gets funky, and I'm too long removed from it to explain it simply and clearly, but Ima try here anyway.

The equation for heat loss q through a 2 dimensional area is represented by:

q = delta T / R.

If you assume the amount of heat you have to lose through the pad is a constant across all or most cold weather situations, then delta T is your body temp minus the air temp, and R is your R value of the pad. As you can see R is on the bottom of the equation, so from that you can infer that as R gets bigger the effect of it getting bigger diminishes....therefore there is a large difference between R = 1 and R=2, but not as much of a difference between R=7 and R=8.

All that to say, the juice is worth the theoretical squeeze more when you're going from R=1 to R=2, or 2 to 3, or 3 to 4, than from 5 to 6, 6 to 7, and 7 to 8.

I bet that made no sense at all, apologies.

 

[Jethro]

Since you have the NXT, I would not get the other pad even if they weighed the same. You’ve already got one of the best pads. I have non NXT and find it to be very warm.

 

[atmat]

You’ll be fine with what you got. I use the Exped 7 (R=7.1) and the ZenBivy Light 10. I stay legitimately warm down below zero.

I could probably do 30-40 degrees below zero comfortably with a hot water bottle and puffies.

At a certain point you’re getting diminished returns and adding weight for something that can be addressed in other ways (hot water bottles, puffies, etc.)

 

[Stave]

For me, Xtherm works 0-40 (haven't camped below zero with it)
Above 40, Xtherm is too warm and I switch to anything light and comfy

 

[hikenhunt]

R-value is a measure of thermal resistance. The math kinda gets funky, and I'm too long removed from it to explain it simply and clearly, but Ima try here anyway.

The equation for heat loss q through a 2 dimensional area is represented by:

q = delta T / R.

If you assume the amount of heat you have to lose through the pad is a constant across all or most cold weather situations, then delta T is your body temp minus the air temp, and R is your R value of the pad. As you can see R is on the bottom of the equation, so from that you can infer that as R gets bigger the effect of it getting bigger diminishes....therefore there is a large difference between R = 1 and R=2, but not as much of a difference between R=7 and R=8.

All that to say, the juice is worth the theoretical squeeze more when you're going from R=1 to R=2, or 2 to 3, or 3 to 4, than from 5 to 6, 6 to 7, and 7 to 8.

I bet that made no sense at all, apologies.

Dos nailed it, you will notice an R value difference of 1.2 at the lower total R values. I doubt anyone can tell the difference between 7.3 and 8.5 at any reasonable tent camping temperatures.

 

[mrbillbrown]

Xtherm for me year round. From Sept elk to spring and summer kayak camping. Zero complaints and it can’t be beat for the weight and warmth.


Sent from my iPhone using Tapatalk

 

[northernmadman]

I use the Eped 8R and it works great. this march had my tent setup testing a new 0 degree C bag lower limit. temps dropped to -22 and the only part of me that was warm was what was resting on the pad. Had to wake up and start the fire, sleep was over lol. Bag was good till about -10 and without the pad I am pretty sure the 5 hours of sleep I got would have been zero and spent all my time and wood stoking the wood stove.
I did have a nice Burbot on the line for breakfast in the morning so it wasn't all bad

Get the pad, comfortable and packs up fairly small. I personally don't mind spending money if it means better sleep and better recovery. As I get older, those things mean more to me.

 

[jamandt]

I always appreciate when I find a thread that asks a question I had and gets great responses that stay on topic!