GG Thinlight w/ BA Insulated Air Core

David, I think you will be pushing the envelope with that set up. Please review this thread
Question of the day
Pay particular attention to Richard Nisley’s remarks.

David,

I haven't been that low w/my BAIAC. However, It was TOASTY at my low of 29 deg. That was w/a quilt.

I my suffer for it, but I would give your proposal a try for an overnighter without hesitation. But it wouldn't hurt to play it safe and carry extra!!!!!!

Todd

Tad,

Thanks for the link. It seems that the BIAC is over-optimistic with its temp rating. Perhaps that explains why my wife and I were cold whilst in our 15 degree bags in 20 degree weather (with the wind howling at 70 mph outside). So…back to my original question, do you think the GG thinlight would provide sufficient warmth in conjunction with the BIAC? I'd hate to add any more weight to my pack as it is.

I appreciate Richard's science based analysis… but will note that different people require different amounts of insulation (e.g. "comfort" is a generic person, not everyone).

I have repeatedly "pushed the envelope" with the BAIAC. For ME, I have been able to sleep through the night with no issues down to somewhere between 20-25F. This is under a quilt, so no extra insulation under me. Several of these nights was on hardpack, so no extra most from pine needles, tall grasses, etc. Somewhere between 20-25F I started to notice a chill coming up through the mat. The nights between 10-15F I was able to sleep, but I was not warm and comfy.

My daughter's experiences are somewhat similar, though I think her breakpoint is more somewhere between 25-32F.

–Mark

No direct experience, but I am leery of BA stats. I love their Seedhouse SL tent almost to death — but curiously, aside from the stats on tents which are mostly accurate — BA stats on bag weights and warmth seem to border on hype. Ditto for their pads too.

Mark,

The relevant International Standard defines the "standard" male as wearing only .6 clo of clothing when sleeping and having these characteristics:

Weight: 70 kg
Height: 1.75 m
Age: 30
Body Surface Area: 1.8 m2
BMR: 44.5 w/m2

Extreme Rating: 6 hours of rest before awakening cold

What are your comparable stats, including the clo level of the clothes worn and the maximum hours slept before awakening?

I have this pad, and thru experimentation, for me, the lower limit without additional closed cell something is 30 degrees. I would rate myself as a medium sleeper, neither hot nor cold. If the temp is going to be near or below 30, i bring help. Hate to be cold at night. Going camping this weekend near Cleveland, with boy scouts, will be mid 20s at night. I will be on my BA with a Ridgerest, or TR pad, (we aren't backpacking, only from car, lol), so weight doesn't matter. I love the pad on hot nights, as it keeps me cooler in the summer, and love it overall, as I am a bony side sleeper who needs the support it offers.

I've been comfy on mine when outside temps hit 10-15. This was inside a double wall tent and I slept in a WM Versalite with no insulating clothing on (just my base trekking layer).

Was this on snow Chris?

No, not on snow. We don't get a lot of that here in the SE.

David, Have you decided what you are going to take. I have had my BaIC down to 27 degree with out a problem but want to take it down to 15 also.

i took a BA Insulated Air Core with a GG thinlight 1/8" down to 5 F. I would not say it was that warm at 5 F but at 20 it will definitely be good to go.

Paul

What bag did you use and was your thinlight pad on top of or below your BA IAC? I just picked up a couple of thinlight pads off gossamergear.com and plan on using one in conjunction with my BA IAC and likely a Marmot Helium bag.

I used a REI Sub Kilo +20 bag. I put the thinlite on top of the BA. I don't think I would do much use under the pad. There is about 2” of air under the insulation you would have to warm before even getting to the the thinlight if it was underneath. I used a BA/30 montbell bag in 30-35 nights with and with out the thinlite and it deficiently helps me. Although I was not that cold at 30 with out the thinlight, I would start getting a little cold very early in the morning. Once I started using the thinlight I was toasty all night long. I have never used at about 20 but I expect it to be warm.

This has been debated, but the folks at Gossamer Gear recommend putting the ThinLight UNDER your sleeping pad. The purpose here would be to stop the ground from cooling the air inside your BA pad. (The air in the BA pad is actually pretty warm when you first blow it up, because it's coming from your lungs….).

I think this makes more sense if you are using a bivy or something else that controls the heat loss on the sides of the BA pad. If not, then the air may cool the BA pad…..although I've used a CC pad with a BA Air Core on top of it, and I've never been chilled by my pad. This has been in a fairly wide range of conditions, high altitude, fairly low temperatures (20's.

Per the above post, I slept on my BA 12/5 and 6 in an open shelter elevated wood sleeping platform. Morning temps were 8 and 11. I used a ridge rest on top of the BA, and a Montbell ulss #2 bag. I was fine, temp wise, and felt no heat being sucked out of me from below. The insulation on the BA pad is supposedly on the top, so adding the pad creates two layers, right below your bag. I think that is better then between the ground and pad, but have not tried it that way.