Anyone ever used two mats? I have an inflatable with no insulation but with lots of cutouts to let the bag loft. This will still be cold in Jan so am going to get a self inflating mat of some sort too. Considering a lightweight one (maybe alpkit airo 120?) and maybe combining with the inflatable. Double warmth! Or maybe just stupid...
It makes perfect sense but sadly it's an idea scuppered by the laws of physics and you won't really be any warmer than you would be just sleeping on the Airo.
I've also read that the R value of the two mats combine to give a higher value.
See, that makes sense to me. So long as you have something that is giving some insulation when used alone (the inflatable I have is a Klymit Ozone r1.4 I think) I can't think why it wouldn't add some extra warmth. Doesn't mean it's not a crap idea though
I've also read that the R value of the two mats combine to give a higher value.
It does but an 'air only' mat has an R value of virtually nothing - 0 + 4 = 4.
See, that makes sense to me. So long as you have something that is giving some insulation when used alone (the inflatable I have is a Klymit Ozone r1.4 I think) I can't think why it wouldn't add some extra warmth. Doesn't mean it's not a crap idea though
This is true but I'm not sure how the Ozone can have an R value of 1.4. Isn't it simply an air mat with cut-outs? I'm sure the benefit of 'bag lofting between the cut-outs' can't be measured with any degree of certainty / accuracy?
See, that makes sense to me. So long as you have something that is giving some insulation when used alone (the inflatable I have is a Klymit Ozone r1.4 I think) I can't think why it wouldn't add some extra warmth. Doesn't mean it's not a crap idea though
This is true but I'm not sure how the Ozone can have an R value of 1.4. Isn't it simply an air mat with cut-outs? I'm sure the benefit of 'bag lofting between the cut-outs' can't be measured with any degree of certainty / accuracy?
Rather at the manufacturers mercy I guess when it comes to quoted R values. And since when has a manufacturer ever lied about their products abilities....
It is possible for an air mat to have insulating properties though isn't it? The Neoair Xlite had a claimed R3.2 and from what I can tell this appears to essentially just be an internally foil coated air mattress.
Most, if not all, insulation in sleeping mats, sleeping bags, duvets, etc. is actually air. The "insulating" material isn't doing the actual insulating it's preventing the air from circulating and removing heat via convection. There will still be convection going on but rather than a big cell of air circulating the insulating material means that the cells are really small and convection is vastly reduced
I've a Klymit X-Frame mat which is to all intents a fancy LiLo. It's a summer to early autumn mat when the ground's warmed up and it's mostly for comfort for my old bones when I want to go really light rather than any thermal properties.
Better weight than wisdom, a traveller cannot carry
It is possible for an air mat to have insulating properties though isn't it? The Neoair Xlite had a claimed R3.2 and from what I can tell this appears to essentially just be an internally foil coated air mattress.
My understanding of the Neoair is that while there's no actual insulation inside, the 'thermal barrier' limits convection by minimising the temp' difference between the top and bottom of the mat which allows the still air inside to act as the insulation.
I have the same understanding. I went from an original Neoair to an XTherm and it's definitely warmer for very little weight penalty. In simplistic terms it has more, smaller baffles
