Hmm the link provided for the Xlite on their website does not seem to work for me.
Nor can I find it by myself on their site. How odd.

Here's the link:

NeoAir Xlite link

Ok I found the problem. At least it looks likely it might "leak" before January.

http://www.summithut.com/products/neo-x-lite-system/

just the x-lite pad,
will be available in just over a month.
http://www.backcountrygear.com/therm-a-rest-neoair-xlite.html
to splurge or not to splurge?

So how long until we start seeing inflatable sleeping bags based on this technology? :)

Seriously though, how is it possible that a bunch of empty baffles can outperform 900fp goose down? Can't wait to see thermal tests. I've an open mind, but remain skeptical.

Edited by dasbin on 12/07/2011 17:03:54 MST.

Outperform? I doubt that. I'm sure there are air pads with 30D fabric and 900 fp down that performs just as well or better. Actually, I know there are, but I don't care to search BPL for those at this time.

Inflatable down sleeping bags have come and gone. I don't see them coming back with an insulation technology that's no better than down. If anything, it would come back with 30D fabric and 900 fp down.

The closest thing that comes to mind is the Kooka Bay custom down pad. They're R 5.9 at around 22oz. I think they're 750fp, but that is not enough to make up for the difference in weight at all.
If you truly do know that there are down mats out there that outperform the claims of the XTherm, in terms of insulation-vs-weight, I would be really interested in seeing them.

I think the Stephenson's DAM has an r-value around 10 at a stated weight of 23oz., although I could be mistaken. Either way I'm interested in seeing an X-therm when they come out

From memory, I remember getting quoted from bender (Kooka Bay) for a 72x24x3.5 mummy
roughly :
apex R5.9 19oz
down R9 22oz

"I'm sure there are air pads with 30D fabric and 900 fp down that performs just as well or better. Actually, I know there are, but I don't care to search BPL for those at this time."

Actually it seems the Xtherm wins as being warmer for the weight than down, although a complete apples to apples comparison is hard to find data on.

Options I could find:
1) NeoAir XTherm = 15oz, R-5.9, 72" x 20" x 2.5" with rounded corners, 30D fabrics

2) Kookabay DAM with R-6, 72" x 20" x 2.5" with TAPERED cut, 70D fabrics = 18.2oz
http://sectionhiker.com/kookabay-down-air-mattress-field-test/

3) Kookabay DAM with R-6, 72" x 24" with TAPERED cut, 30D fabrics = 16.97oz
http://www.suluk46.com/RandD%20-%20RD27%20Kookabay%20Custom%20DAM.html

Discussion:
The option #3 Kookabay pad is very close spec-wise to the Xterm (30D nylon, 72" long, same R-value, same thickness). The main difference is that it's 24" wide, but that's at the widest point and it's got a heavily tapered shape (see pic @ link). It tapers to about 12" at both ends, so from the looks of it, there is a very similar amount of pad present here. Assuming they have the same area (big assumption) then the DAM is 2oz heavier than the Xtherm.

Option #2 definitely has far less total pad area, as it's a 72" x 20" x 2.5" with a tapered cut that shaves off a lot more area than the rounded corners of the Xtherm. Yet the total weigh is 3.2oz higher at 18.2oz. This pad does use significantly heavier 70D fabrics, so the question is whether that would drop the pads weight to quite a bit less than the Xtherms 15oz, because this pad is clearly narrower (on average due to its tapered cut). This pad would probably have to weigh about 13oz to be just as warm for the weight as the Xtherm, since it appears to have 10-20% less surface area. Could 30D fabrics shave this much weigh (~5oz)? Maybe, but IMO the best case scenario for DAMs is that they equal the performance of the Xtherm. Apples to apples is hard to do, but it seems the Xtherm weighs the same or a bit less as a 30D DAM.

How does the X-therm achieve this? My understanding is that the basic Neoair design incorporates several layers of metallized film (like space blankets) that have bond lines at intervals so the whole assemblage has a honeycomb-like cross-section when the pad is inflated (like a "Blizzard Bag"). Is this consistent with the understanding of others? Does anyone know the approximate size of the cells that form between the layers of film (or the number of cells between the user and the ground)?

I just find the (alleged) performance of the X-therm unexpected given what little I understand of the design.

I think that is about right.

I think the IR reflection could indeed be very high... but convection insulation is of even greater importance in most situations. The "honeycomb" baffles would stop some convection, but no matter how many or how small the baffles are, I just can't see it beating the air-trapping ability of good down clusters. Wouldn't you basically have to make the baffles the size of down fibers? The sheer amount of fabric required to do so would make it real heavy real quick, no matter how thin and light the fabric was.

I suppose the big theoretical advantage that sleeping pads have is that they don't have to be breathable. But if you're going down that road, why not just use silica aerogel?
It almost seems like these fabric baffles can meet or beat the performance of aerogel! Haven't done the math but the warmth/weight ratio looks not far off. It's so hard to believe.

I don't know. All conjecture. Just doesn't quite make sense to me... want to see testing.

Edited by dasbin on 12/08/2011 19:49:07 MST.

For future imaginary products, what about a Neo-Air Xtherm filled with down. Maybe Call it the Neo-Air D-therm

You would get the best of both worlds!

Not sure about the construction side of things and how it would all come together. Also it would be heavier then no down at all, but think about squeezing 4-5 oz of down in the X therm. for around 19-20oz the R value would be quite high I imagine. MYOG project anyone?

Except some the first few nights, I noticed little noise. The BA mats make a ton more from my personal listening experience in the field.
Duane

I have formed a theory about the Neo Air "noise".
The sound produced by it travels at a particular wavelength that is inaudible to the owners but can easily be heard by anyone else.
Same wavelength used by incessantly barking dogs.

For the record, I cannot hear the noise from MY Neo Air.
Franco

Backcountry Gear and CampSaver both have the Xtherm listed (http://www.campsaver.com/neoair-xtherm-sleeping-pad & http://www.backcountrygear.com/therm-a-rest-neoair-xtherm.html) for $150 USD. Not long now.

I am still waiting for some accurate measurements of the packed size (to compare the Xlite and Xtherm). Hopefully the Xtherm is not TOO much larger!

Think I'm gonna go with the Xlite in a large and keep using my old BAIAC on colder trips for now. $180 is tough to throw down though. Cant wait for some testing on the Xtherm.

Ryan

"I think the IR reflection could indeed be very high... but convection insulation is of even greater importance in most situations. The "honeycomb" baffles would stop some convection, but no matter how many or how small the baffles are, I just can't see it beating the air-trapping ability of good down clusters."

Well since hot air rises and the heat source is above the pad, I would guess that advection (transfer by the bulk movement of air) is not a huge source of heat transfer in sleeping mats. Diffusion of heat will be an issue with both down and reflective baffles, but the baffles might actually do better since heat has to diffuse from air to plastic to air several times.

And I seem to remember, a few years ago, people here trying blizzard bags rather than conventional sleeping bags as they were warmer for the weight.

"I would guess that advection (transfer by the bulk movement of air) is not a huge source of heat transfer in sleeping mats"

Good point, unfortunatly the warmest parts of our bodies (butt and back) typically "sink" towards the middle of an airmat's thickness - creating a nice natural convection path towards the higher, colder perimeter of the pad, still probably not as bad as if the heat source was on the bottom though.
Also, we are hardly still during sleep (breathing, rolling around, etc...).