Warmest-for-the-weight winter mattress

I sleep cold. So I’ve looked at a lot of pads and I haven’t found one better in terms of your (and my) criteria.  Mine gets used year round. Warm and light!  As a side benefit, the tougher bottom material is a good thing.

I love having a one-sleeping pad quiver, and this pad is it. The noise either has stopped or I just have completely tuned it out, and it was not a failure point down to 20 degrees F, which is the coldest I have taken it (had a zero deg down quilt, so I actually overheated; packed my fears).  It’s definitely spendy, but it’s a one-pad solution.

Anyhow, just wanted to concur that I love my xtherm. =)

Exped downmat winterlite. better pad unless you place weight above all else.

2oz heavier, but warmer—r=7 v 5.7–nearly the same packed size, inflation bladder if you want it, laminated top seems more durable and has more grip, not as noisy (still crinkly though), 1″ thicker (helps to adjust firmness), and side ‘wings’ are nice to keep you from wandering off the sides.

In the field, noticeably warmer and more comfortable, do not notice the 5oz gain (2 for pad, 3 for inflation bladder).

After spending time with all the popular pads including a custom down mattress, I am sold on the ex-therm for year round use as well.  Exped ul7 is a close runner up, but after two failures I opted out but my son still uses and abuses my old downmat 7 with the bomber fabric and 32oz weight.

“the Thermarest Neo-Air X-Therm is the warmest-for-weight winter mattress available.”

Well that’s if you actually trust their own measurements, which I don’t.

What leads you to believe the ratings are inaccurate? General skepticism or do you have some facts?

If you’re camping on snow, then you might want to factor in a closed cell foam pad into your sleep system to reduce conductive heat loss to the snow.

“General skepticism or do you have some facts?”

A little of both.

https://thermarestblog.com/r-value-meaning/

Since Cascade Designs tests their pads using metal plates in a 39 degree shipping container, I only “trust” the accuracy of their R values based on those very narrow conditions. While I think it was a noble undertaking for pad companies even attempt to articulate their sleeping pads using R value as a metric, there are many problems with this:

1. R value originates from the building insulation industry. Building insulation products have very specific independent testing requirements depending on the type of insulation. In other words; the testing methods for rigid insulation are different than for loose filled insulation. While the end result is an established R value, they aren’t tested the same way to derive that number. Not only does the lack of third party verification in sleeping pads make it impossible to compare between different companies, the “metal plate” method might work reliably for closed celled foam pads, I believe air mattresses insulate very differently, have more variables to consider, and should therefore be tested differently.
2. It is common knowledge that the R value of any mattress can be impacted if the pad is subjected to compression. Therefore, if a pad is highly compressible, it runs the risk of a wide variation in it’s R value. Back in 2011, Roger Caffin measured on the original Neo-Rest that if you compressed it’s thickness in half, it’s R value was cut in half. While Cascade Designs listed it’s R value as the mid range between it’s Rmin and Rmax values, this becomes a big issue for folks who either under inflate the pad to improve it’s comfort, or sleep on their side.  Since the X-therm can be compressed with the same ease that the original Neo-rest can, (barring any additional info from Cascade Designs), I can only expect that the R value of the X therm will be impacted by the compression as well.
3. On a 2.5″ thick pad in very cold weather, the temperature difference between the pad’s edge and it’s top & bottom faces will be an issue. While it’s purely conjecture, I believe that any slight movement on an air mattress will circulate the air inside the pad, thus impacting it’s R value. The above testing method doesn’t contemplate any movement in the pad. Obviously closed celled foam pads won’t have this issue.

There are several more issues which have been brought up in previous threads on this subject (especially the emerging issue with temperature dependence of R values) , but if X-Therm were truly performing at it’s R value of 5.7, I don’t think there’d be the number of seasoned campers out there complaining about feeling “cold” while using it on a winter trip. Furthermore, if we have to ask ourselves why we always recommend a closed celled pad when winter camping, it clearly points to a general “distrust” in the stated R values. If that wasn’t the case, then why wouldn’t people just recommend adding an X-Lite to one’s system, since it’s lighter than many closed celled pads, and has a larger measured R value than a RidgeRest Classic (at least according to Cascade Designs.)

Until some third party verification is in place, I’d love to see the pad manufactures simply show their R values as a range for air mattresses, instead of just a single number. That way it would give people pause when they try to research the “lightest and warmest” in a given category. The risk for the companies might be less sales, since I may end up with a $25 dollar foam pad instead of a $150 dollar inflatable pad, since it might end up being “warmer” than the lower end of an X-Therm’s range.

While I have only used my XTherm to the high teens it has been plenty warm.  I have used an Exped Downmat UL7 down to 0*F and been warm.   I do think a ridgerest is warmer than an air pad with the same r value.

We should all contribute data and invent a new unit, the danepacker:  (area * r value)  / weight

That will control for slightly different size pads.  We could use volume if people really want to be fussy.

I have a Synmat UL 7 that I will measure if this suggestion “holds air”

For the purposes of these types of discussions stated R-value should be fine.  There will be anecdotal posts on both sides of the argument (x pad was cold/warm for me).  R-value is a pretty loaded term, even in architecture building shell products have a tested performance, but its the whole not the sum of the parts that matters.  Short of building a test room stated R is all we got

Well, I know the XLite is NOT the one to use in winter. Much of the additional insulation (ie, beyond a normal and expected R2.5) is due to the IR barrier. While this works, it isn’t that much. Say an additional 8-10% of a persons generated heat. Note that ONLY ONE will work to any effective degree. The rest is confined to air pocketing (limiting convectional losses.) Of course, there is something to be said for the nobel gasses as in the first generation of stuff from Klymit.

Regardless of how a pad is tested, I agree with Matt. Compression will influence all pads. Air filled pads more than CCF pads. A plate testing does not capture this. And, without the typical movements a person makes throughout a night, the inaccuracy could be even higher.

So, for the warmest for the weight pad, I would choose a down filled air mattress. A Stephensons D.A.M. is a good choice. It weigh’s around 22-24oz and is 4″ thick. This will insulate you from rock at around -15F. Snow/forest duff provides additional insulation, so, it is good much lower that that on snow or forest duff. The key points are that the air provides the structure, and, the down provides the insulation. Even 2″ of down provides plenty of insulation below you. It doesn’t bleed heat from the edges as the NeoAirs do. The only addition I would recommend would be an aluminized emergency blanket at around 2oz.

While down insulated pads are quite warm,  I would be very curious what the total R value per gram of a pair of thin ccf’s sandwiching a light air mattress might measure out to be.

Anybody used an X-Therm alone (without supplemental CCF) from about 0°F to -10°F?

Anybody used an X-Therm alone (without supplemental CCF) from about 0°F to -10°F?

Bob,

Several years ago Richard Nisley posted a graph of a very large number of data points.  Y-axis was ground surface temperature and x-axis was air temperature.   It was a classic “hockey stick” profile with tightly packed points and few outliers. The ground temp was flat at about 32F for air temps at or below 32F.  On snow?  I dunno, but since snow is a reasonably good insulator I’d expect the same.

But I have no experience on a X-Therm but I’ve slept on snow a few times in the -13F to 0F range long ago on a classic ridgerest on top of a classic self inflating t-rest.  Was warm, at least until I got up in the morning.

Thanks, Jim.

I’ve slept many times with a set-up similar to yours with an old-style TR self-inflator on top of a CCF (the yellow Evazote) mat. Man, was that a heavy combination! But it worked pretty darn well many times down to -20°F and sometimes lower.

My current combo is working well and is pretty light. It is a NeoAir Trekker torso wide (47″x25″, 13 oz) combined with a full-length 3/8″ EVA mat (7.5oz) with my pack under my lower legs, which I’ve used down to -5° or so.

The only thing that interests me about the X-Therm is that it could be a one-piece solution that fits inside my pack—if it works—and eliminates the bulky CCF mat on the outside. Maybe after New Year and the holiday hubbub I’ll go the buy-try-return route at REI.

I’d also like to try a down air mat but I had exactly one anecdotal, second-hand experience that raised a red flag for me. My buddy Jon used one (Exped Downmat) on a trip to the Catskills where it got down to about zero overnight. Next morning when we were breaking camp I had a chance to check the snow beneath his sleep mat and found significant melting, which of course indicates a lot of heat loss. The melting under my Trekker/CCF combo was very little.

I’m with Matt in that I don’t put much stock in the R values. Very little in fact. As a quick example, the RidgeRest is given an R value of 2.8 and an X-Lite is R 3.2. From personal experience I know without a doubt that the RR by itself is a LOT warmer than an X-Lite, and also that the Trekker at R 3.0 also seems warmer to me than the X-Lite.

I also used a Synmat 7 (R 4.9) down to about +15°F a few times. I didn’t freeze but it could have been warmer, and I ended up putting the CCF on top of that. After experimenting with the GG Thinlight (1/8″ EVA) the RidgeRest and the 3/8″ EVA, the latter ended up with the best warmth/weight/bulk combo.

When all is said and done I personally have a hard time envisioning a winter sleep system that does not include some CCF, and from what I’ve experienced it is more important than the air mattress. :^/

But I’d like to be proven wrong and perhaps the X-Therm can do that.

Bob I wouldn’t give up the CCF, Xtherm or other inflatable pad. Having a reliable system or backup system is essential during cold weather with sparse daylight hours. If you found yourself in the middle of the night with a punctured inflatable and no CCF, you’ll survive given shelter and warm layers/bag, but it’s probably going to be a miserable night. Also the CCF does double duty folded over as a warm sit pad on snow and a long pad for legs/back on a carved-out snow kitchen bench.

Ethan, that’s a very good argument for sticking with my current setup!

Ethan’s comments about CCF pads offering pad redundancy is important, especially if crampons or bulky double boots are part of your kit (they tend to poke things unexpectedly, especially when your hands are cold). And using the CCF as a sit pad is really helpful when camping on snow, either in a tent or in a snow cave. Stuffing clothing, a pack and/or an emergency blanket underneath an inflatable pad or sitting on them instead of carrying a CCF while snow camping is bordering on “stupid light” IMHO, especially if you’re in an isolated area far from a trailhead.

An additional benefit of a CCF pad under your inflatable during winter camping is heat loss when you’re sleeping on your side. Unless you are shaped like a bean pole, or never sleep on your side, or you keep your inflatable pad pressure really high, then side sleeping pushes your hips and shoulders deep into the inflatable pad, making those areas noticeable cold spots. The effect is minimal in 3 seasons because the ground is relatively warm, but it’s exacerbated when sleeping on snow. A 3/8″ CCF pad remedies this.

I agree about using both. I always carry at least a 50″, 3/4″ CCF pad, just for support in my pack. But, Eric wanted warmest-for-the-weight winter mattress. So, I suggested one of the down filled air mattresses. I have had them balloon out, go flat, and am well aware of the possibility of a puncture. Carry both, sort’a like layering cloths. Each serves a different purpose, and neither provides the entire solution. A down pad and a CCF pad provide a good solution to cold weather. If only one must be chosen (ignoring dollars,) go for a dam…and stay off ice and rock.

Just anecdotal evidence here…

I run very cold. I’ve been using the XTherm all summer and fall, but still find that I get cold below 50° with a 30° half quilt and hoodie, midweight Smartwool baselayers, and often a GG thinlight CCF pad on top. It  is my designated summer pad, though. I have the short and regular lengths, and I only use the short for SUL weekender trips. However, for winter or any temps below 50° when I’m not experimenting with SUL, I now use the Exped Downmat Winterlite with or without a short  solite RidgeRest. I am significantly warmer with the Exped compared to the XTherm. I used my 30° half quilt and hoodie in the snow in temps down to 19° with the RidgeRest and Exped mat, and was quite cozy, especially where the short CCF pad was stacked. I wish they made a high-R value and lightweight CCF pad, but for now I’m satisfied with two separate air pads for summer and winter. If you don’t run cold, I would think the XTherm would be just fine in the winter. But the CCF pad has been very useful for sitting around camp on snow and changing clothes outside when your tent is too small. :)

Since this thread is in the SUL threads, I’m curious…are you doing winter SUL trips? Are SUL baseweights in winter the same as summer (<5 lbs.)? If so, that’s impressive (and impossible for me)!

CCF & WINTER PADS:

I have a Ridgerest pad and have used it in -5 F. temps under a 3/4 Thermarest (original version, no less).

Now I have found a thin (1/8″) CCF floor underlayment pad seems to work very well under my Thermarest ProLite summer mattress down to 10 F. on forest duff. I trimmed it to match the ProLite shape to save weight. I tested it by itself on my cold cement patio pad and found it quite insulating.

*Full Disclosure-> I always lay my pants and other “day time” clothing under my sleeping pad(s) for extra insulation.

UPDATE:

My new winter air mattress is an REI FLASH INSULATED All Season at around 17 oz. for a regular length, mummy shape. It’s rated at R 5.3 which should be good to at least 0 F.

And I also bought the REI FLASH INSULATED 3 season air mattress. 15 oz., R 3.7

I got a valve-compatible Sea to Summit dry bag/inflation bag B/C I refuse to blow up an air mattress at 9,000 ft. by mouth.