I never really thought of self-inflating mattresses as being very good at self inflating - I always blow mine up - but I suppose a 2.5" thick air mattress with no foam to start the job would take a lot more wind. It's good then that I am full of hot air.
I think that DAMs require a pump of some sort to inflate since it is better to avoid the moisture that is present when blowing up an air mattress. What about for a synthetic fill air mattress (SAM)? The POE air mattress says it doesn't require a pump. Is that wishful thinking? Would I need to inflate it with non-lung air to get the full insulation value out of the synthetic fill?
Sorry to hijack this thread with questions about the technicalities of insulated air mattresses.
13 ounces for a winter pad system seems very light. I've been looking at R values a bit, and while I'm not sure exactly what they mean it seems that an insulative material has an R value/unit length, and that R value is linear with pad thickness. So for the pads on, say, Gossamer Gear's website, the insulation value of the normal foam pads is 3.6R/1". So the 1/8" pad is .45R, the 1/4" is .9R, etc. (doesn't quite work since the 3/8" is 1.42R instead of the expected 1.35R, but maybe it's a slightly different type of foam).
I think, once we calculate the overall R value for a pad (R/Thickness * Thickness), we can simply add the R values of two pads stacked on top of each other to get the total R value for the pad system (so a Torsolite, with an R value of 3.5, on top of a 1/8" Thinlight, with an R value of .45R, would give insulation of 4R in the torso and .45R under the legs). Does this make sense? I'm kindof thinking of it as serial impedance for an electrical circuit. Except with heat.
Anyway, if this thinking is sound perhaps it would be useful to figure out what your needs for winter torso and leg insulation are (the R values for your 13 ounce system, taking into account whether you feel cold when using it), and then try to piece pads together to get the insulation you need for as light as possible.
Comparing full length pads: The POE Ether Thermo 6 has a torso R value of 7.8 and a R value of 6.8 for the legs (if the REI website is to believed). It weights 21 ounces, so we if assume an R of 7, this is .333R/ounce. The Exped Downmat 9 has an R value of 8 and weights 32 ounces, giving .25R/ounce. The Gossamer Gear Thinlight 3/8" pad has an R value of 1.42 and a total weight of 5.5 oz. This gives .26R/ounce. So it seems that DAM/SAM are roughly equivalent to certain types of foam pads. But both seem to be superior to self-inflating pads on the R/ounce front (POE AO Mtn: ~.16R/ounce, Thermarest Prolite 4: ~.13R/ounce).
Other types, like the Nightlight pad, have higher R/ounce values (.65R/ounce in the case of the Nightlight).
So it looks like the best system, from an insulation standpoint, would be to combine foam pads with high R/ounce values to get just the insulation you need in the torso and legs. And there is no inflation necessary. But a DAM or SAM would fold up way smaller and would provide some cushiness to boot, which I like.