S2S Ether Light XT Extreme

6.2 R value, but heavy (maybe 25 oz)

seems heavy (950 for reg wide) but 4” thick!!! I have my BA q-core and at 3.5”(?) I like it more than my AXL in terms of side sleeping comfort. For a side sleeper, this s2s might be worth the weight over the Neoair Xtherm.

I haven’t used any of the S2S Ether Light pads but people who have rave about the comfort.

Apparently the pads are also very reliable, a big plus for winter use. In winter, I always take an EVA pad in addition to an inflatable as emergency backup (unhappy experiences with pad failure), so maybe this could work for me in place of the combo if the reliability were really consistent.

I’d be interested in hearing from Ether Light users in general about their experience with durability.

There has been some discussion of how user movement affects pads differently, making some pads warmer in use. For all I know this might be little more than anecdotal or an internet meme. I guess I wouldn’t be surprised, though, if this S2S pad, at an R-value of 6.2 compared to the 6.9 of an Xtherm, turns out to feel warmer in use than an Xtherm because of different chamber construction, especially when side sleeping.

Too bad the RW version adds 230 grams to the weight compared to the R version. 950 grams is heavy. But there are other options:

The women’s R version is slightly lighter than the R version at 685 vs 720 grams and has a 6.3 R-value to boot.

There is also a women’s L version, which is sized like the RW version except with tapered female-friendly shape (thinner in the shoulders, broader in the hips, still same max width), that is 870 grams, 80 grams less than the RW.

I used a Sea to Summit Etherlite XT insulated (R=3.2) for a year and a half, backpacking in the Pacific NW. In general I liked it, it’s a very comfortable mat, but it never seemed like it lived up to the 3.2 R value and was less insulation than a foam mat with 2.2 R value. I sleep on the colder side, but I was regularly feeling the cold from below in even moderate temps (below low 50s or on ground that didn’t insulate well).

So I reached out to S2S to ask about this. They were super helpful and responsive, I’ll copy the reply below, as well as their reply to a couple of follow up questions. There’s a note towards the end about comparison to the Thermarest design, and the successful outcome for me was that I switched to a Thermarest XTherm for my backpacking and have been super happy — super warm and slightly lighter, and I like the firmer feel (my preference). Kept the Etherlite for summer car camping.

The new S2S XT extreme may address these issues, I don’t know, but the insulation on the XT insulated didn’t meet my needs. I’d be curious to compare to the Thermarest XLite in the real world, but haven’t done that.

———————–

Here’s the responses (in italics) from S2S customer service:

The Ether Light is tested for resistance to heat loss (R-Value) according to the ASTM protocol; this yields a value of 3.2 (compared to the previous test protocol which yielded 3.8).

The insulation of an insulated air pad (including the Ether Light) is designed to prevent the exchange of warm air (from the sleeper) with the cold air next to the ground, a process known as convection. The insulation (in the case of the Ether Light the insulation is Thermolite, plus a reflective layer called Exkin Platinum) forms a lofting layer which prevents the air moving freely from top to bottom within the mat. In contrast, there is no air movement at all through a closed-cell foam pad like the RidgeRest.

The Ether Light has a layer of Thermolite insulation which weighs 100g / m² (compared to the 60g / m² of some competing air pads)

However, the ‘skin’ of the sleeping pad (this is true for all air mats) is not insulated from the surrounding air. When an air pad is inflated, the air inside the pad quickly assumes the ambient air temperature. The sleeper needs to warm up the air inside the pad, and with a large-volume design such as the Ether Light, this takes a while.

Air movement within a pad may be a factor that affects the warming of the internal air.

My follow up questions:

1) Does inflation level of the Etherlite make a difference in heat transference? i.e., should I be pumping it up as firm as possible, or can there be a slight amount of give and still be equally effective?
You ask excellent questions that many in the outdoor industry overlook. If a thick pad is inflated too firmly, the user will experience the ’bouncy castle’ effect which is quite uncomfortable. At the other end of the scale, if a pad is under-inflated, it increases the amount of air which is pumped back and forth throughout the mat as the sleeper turns over (the sleeper warms the portion under his or her torso; this warm air is pushed off to the perimeter of an under-inflated or unstable mat and dissipates). The ideal is to find a pressure which is comfortable, but which minimizes internal air movement – in the Ether Light this will be about 0.5 – 0.6 psi. The Ether Light is a lot more stable than some thicker pads, the chambers of which suffer significant deflection and thus significant internal air movement at normal sleeping pressures.

2) I think you addressed this, but would you say the convection issue you described is unique to the Etherlite mat design, or common to all blow-up backpacking (lightweight) air mattresses from Sea to Summit or other makes?
o    Therm-a-Rest pads have a complex baffled design with a film halfway up between the bottom and top of the mat: this effectively stops top-to-bottom convective air movement (and the internal pumping movement described above). The design does have several drawbacks.

o    Most other air pads use a polyester mass (or in the case of Exped, down) to reduce convection. In the case of Sea to Summit mats, this polyester mass is Thermolite-branded fibers; in the Unisex mats this weighs 100g / m² (as I mentioned in my last email, some pads on the market use 60g / m² insulation)

I’ve heard and read similar things about the S2S Ether light XT Insulated – on the cooler side of 3.2.  I’ve been very happy w my Nemo Tensor Insulated.

Those are some incredibly detailed responses from S2S customer service. Refreshing to see non-canned answers.

Yes I was thinking the same thing. Makes me want to try out some of their products, someday.

If camping in winter OK.  For 3 season use, 4 inches (10 cm) of thickness would be overkill.  Don’t need to camp in a hotel.  With a good shorty, booties, and puffies if needed, and a good bag, can be comfy for much less weight.  And the puffies can be worn in camp, so do dual use. This winter was short, with endless freeze/thaw cycles making layers of honeycomb weak ice; but understand that for some winter calls.  Or maybe if jet-setting off to Nepal.  Not my bag.

I like how the standard width of the S2S pads is 21.5″ as opposed to the 20″ of the neo-airs. I wish Thermarest did that-their 20″ width is silly narrow in practice due to how the sides collapse when weighted.

But, the Xtherm mattress is so very warm, and lightweight, and compact. It seems, at the present, invincible.

I’ve done a fair bit of winter camping this winter, in temps down to 19F, camping on the snow, and the Xtherm is my go-to pad..I have never felt cold underneath me with the Xtherm.

Here in the PNW, on our trips, we can easily end-up camping on snow even in July. So, having a light pad that will be warm enough, no matter what, is a big win for me.

That being said, if S2S could make their pad, say, 3″ thick, instead of 4″, maybe the weight would be more competitive (unless the thickness is giving the pad some of its R-value).

From local comments the new pad is more about comfort than R value.
The downside is needing a taller and longer tent to accommodate the height of the mat.
I am tempted except that I doubt I’ll be doing much more bushwalking after Covid lockdowns finish.

The additional 1” is not going to add a  significant amount of weight. Even if the additional 1” required 2” of additional fabric around the perimeter, it would result in less than .3 sqyd of fabric. What does this fabric weigh? Even a fabric weighing 3osy would not add more than 1oz. I am happy to have a thicker pad – I have both an AXL and a Q-core. Even though there is only a .25” thickness difference, I prefer the thicker Q-core. I still bottom out sometimes as a very active side sleeper – it is not a big deal, but thicker is always better for me, as long as it isn’t a huge weight penalty.