Big Agnes

Well I actually bought (sort of) a new piece of gear!!!!! My old Stevensons down air mattress valve has a leak around it so I pulled out my Big Agnes insulated air mattress, the one that failed the first night I used it in 2004. I came close to throwing it in the trash several times and had I located it during the recent purge it would have gone to the dump too. Anyway I took it back to REI and they wouldn't replace it but they gave me credit for the $65 I spent on it and I bought a new one - 72"x20"2.5 mummy for an additional $20. It has prim-aloft fill and has an additional 2 tags attached to the case so I suppose its new and improved. Anyway how warm are these things? Do I need a foam pad on top in the winter? I generally carry a Zrester winter camping to use as a chair liner in a packed snowdrift and put in under my DAM, does it need to go on top of the Big Agnes? I'm thinking of gluing my foam pillow (3.65oz) to it so it won't slide off.
Jim

REI says that baby is R 4.1. An Exped Downmat 7 (if anything perhaps less warm than your DAM) is R 5.9. The pads I use on the snow add up to around R 5, which seems to work pretty well.

You are already carrying the Zrest. Why not just use it on top? P for plenty.

I've always heard that you use non inflating foam pads on the bottom and then self inflating or air core pads on top. I have to imagine that sleeping directly on an air core mat would be more comfortable than sleeping on a foam pad on top of an air core.
BTW I use BA dual core (R5) in the winter and has yet to let me down. I use directly on the tent floor and nothing else.

Thanks for the input everyone,
I have a feeling that the air in the mattress would be really cold under the foam pad and might not add a lot of insulation but would still make the bed softer. Maybe putting the foam under the air mattress like I've always done with my DAM might add the insulating qualities of the foam pad to those of the air mattress more because the air would warm up more in the air mattress. Its been my experience that sleeping on the DAM is more comfortable with the pad under it and the air mattress is slick so you can roll over without the pad being pushed off the top, so I think I will continue to put the zrester under the air mattress.
Jim

The only time I've tested out the pad-on-top vs. pad-underneath the air pad issue was with the NeoAir in early October. While I was still shivering (the 1/8" CCF pad was not nearly enough!), I was slightly warmer with the CCF pad on top. The ground was not yet frozen, and that could make a difference, as could snow. For what it's worth, the internal insulation in the BA (and POE) insulated air pads is on the top side of the pad. The NeoAir, of course, has no insulation, just those internal baffles that supposedly reflect your body heat back at you.

I suggest trying both ways with your BA pad and the Ridge Rest and letting the rest of us know!

I have a "big" BA that adore. it's quite warm, but I do sleep cold. I find it pretty good for me down to about -10C on it's own, but below that I top it with a blue foam pad. If I'm expecting serious cold (like this week) i.e. -40 - I use another blue foam pad underneath it.

Mine's the big (25" wide) square insulated Aircore though - not the mummy

I have the Big Agnes insulated mummy style, I use 1/2 a zrest under my lower back and hip area cause that seems to be what gets closest to the ground, hips push down more in almost any position. The other 1/2 of my zrest is for my dog.

bigb
I guess yer saying that you use the zrest on top because of the hip compression thing. I guess just from the point of view of hip compression, putting it under should have the same effect as putting it on top wouldn't it? If you do put it on top, do you have problems rolling over in your bag, that is of pushing the zrest off the top of your big agnes? I tend to rotate the entire bag with me when I turn so the little breathing hole is in the right spot and I like a slippery top to my air mattress so its easier to roll over.
Jim

I told you your better with a keyboard, I actually put the zrest under the pad, I stayed warm on my last trip, it was 17 degrees and I was in a 3 season tent with a 20 degree montbell bag, BA insulated air mattress and the centraly located zrest, and the ground was very much frozen. My next trip should be even colder which will be an even better test, and I was wearing long johns, synthetic bottoms and wool top.