Air isn't a good insulater, unless there are baffles in the design to stop air movement. An airbed sleeping mat is no use in winter for that reason.
I've read about a US company who use a similar idea. The system they use involves the gas Argon. You carry a little can of it (similar to the little cans used for quick inflation of bike tyres) Seemingly Argon is a better insulator? Unfortunately you would need a can of Argon every time you wanted to inflate the jacket.
Now for divers, down is obviously a daft idea (unless you're a duck of course). The point of an inflating gas dry suit is to withstand the compression of diving as well as insulate. I can see how the quoted 10-20% gain in insulation might be worth considering in those circumstances.
But on land? Unless you're in very high winds, I just don't see argon-filled chambers being warmer than down filled baffles. Air and Argon are both excellent insulators against conduction but the reason that down makes such a good insulative material is that it reduces (effectively stops) natural convection currents. If you wore an inflatable suit it would be convection that would rob you of heat more than conduction IMO, especially if you add the forced convection associated with moving your body around.
Of course, I can see some applications - such as boating use (especially if they could rate the garment as a floatation aid). But down filled fabrics are (again IMO) going to be more breathable, lighter, warmer and quite possibly cheaper. The inflatable jackets would get points for water resistance. But as for breathability? Very puzzled about this one. If your sweat passes from you through the inner layer, isn't there a good chance it'll condense inside the air chambers - afterall, the outer layer is going to be colder? So won't you risk wearing a load of chambers with moisture trapped inside them, especially if you fill it from your breath?
A friend (gadget magnet!) bought one of the Gore ski jackets but I never heard him speak about it after a very big outlay. I'll ask him if it was any good!
Well, is not actually new. I-ve got an inflating gillet for over a year now. Is detachable from a waterproof jacket I-ve got from Tommy Hilfiger. And to be honest, I-m very please with how it works the inflating protection. tried it many times, and while other friends stop to put on and out layers, i just inflate and deinflate.
Inflatable gilets? They called them lifejackets when I were a lad, or life preservers or Mae Wests or flotation aids. I bet they're really breathable...into.
> Maybe I'm confused, but I don't see how something that must be airtight can be breathable at all...
The term 'breathable', when applied to waterproof fabrics, usually refers to the ability to pass water vapour, not gas. PU membranes do this by 'conducting' the water molecule along nice long PU molecules in the coating; in one side, and out the other side, using a diffusion process. The diffusion is driven by the temperature and humidity gradient across the membrane.
Pure expanded PTFE (as used in Gore-Tex and Event) is a gas permeable membrane with real holes (pores) in it, so air will pass through it. However, in the Gore-Tex membrane, a thin coating of PU is applied to protect the ePTFE from oleic contamination (oil), which would otherwise attract dirt which would cause a compromise of the membrane by osmosis; it would 'pull' water through the pores in the membrane. Event uses a different method of protection.
I'm with John on the condensation within the air void one; don't see where else it can go, and, since there's a temperature gradient across air gap, this can only lead to condensation, AFAIS. On the other hand, filling the air space by blowing into it will also add water to it; that's my experience of breath-inflated sleeping mats, such as the POE Max Thermo (I keep meaning to build a 'respirator' to inflate and deflate the mat, leaning against a radiator, to dry the insides out...)
This is from last month, hiking in South Korea.
...into.
