>> i have the 32 bag, xtherm pad, 2 layers of down jackets and various wool/base for my top.

Keep in mind that those down jackets require space to loft in order to insulate effectively. Depending on your build and the cut of your bag, you may end up with twice as much weight but still be freezing.

It will work if:
you are a warm sleeper
you are well fed
you are inside a full doublewall tent(non mesh)
On a very warm and large pad (make sure it's wide enough for the huge winter bag).
Wearing SERIOUS parka, pants and down slippers over heavyweight baselayers, including balaclava

all this fit's without compressing the loft of bag or clothing.

I have a very roomy down mummy bag, maybe 15F rated, that I use regularly with a breathable bivy outside at 0F. Wearing mernio top, full powerstretch top, bottom, balaclava and gloves, DAS Parka, Chugatch pants and huge down slippers. However, I sleep cold, you might get away with less.

One way would be simply to stack up your clothes and bag and measure the loft. How does it compare to a 0F bag?

For other options:
rent/borrow
bivy + tent
overbag/quilt (can be anything you or a friend have lying around.)

Several years ago, my wife and kids camped out in north Alabama during February at the Walls of Jericho....were expecting low 30's overnight, but it unexpectedly dropped down to 14. We both had Ultralamina 32 bags, wore clothes, had Prolite pads and 3 1/2 season tents....and we froze our buns off. My wife's Raynaud's about killed her, and I was so cold I was shivering uncontrollably. Fortunately my kids were in warmer bags and were fine, but that was the most scared and closest to hypothermia I've ever been. No way in the world that you can take that particular bag to 0 degrees. If it had dropped to 0 on that particular night I truly think we would have perished.

There's also a distinction about warmth that is being neglected. Above freezing temps require less insulation to provide more warmth than sub-freezing temps. What I mean is that if it takes (hypothetical numbers to illustrate point) 1 inch of down to give you a 10dF improvement in warmth, below freezing it will take 1.5 inches to provide the same benefit. As the temps get colder, the necessary insulation increases. This probably has something to do with our bodies being able to tolerate chilled blood for a while (hypothermia doesn't kill immediately) but being completely incapable of tolerating blood that is frozen solid (severe frostbite results in necrosis).

So what does this mean for you? Well your bag is designed to work at the limits of above freezing temps and has no consideration for sub freezing weather. I'd say rent a proper winter bag and don't risk life or limb to the cold.

You asked if you would regret it. Yes, yes I think you would regret it. Especially since you could rent one or just abuse some store's return policy.

An 8000m down suit would complement a 32º bag quite nicely.

Hardly weight or space-effecient though. And much more costly than a winter sleeping bag.

Like others have said, yes you'd probably regret it. Some super experienced adventurer types get away with that set up on marathon efforts where you might hope to get a quick nap or shiver bivy before getting moving again. Thats not to say its a good idea even for them. I have a conservatively rated 15 degree rated down quilt that I've taken to a bit below 0, but I wouldn't try the 32 if you care about your toes.

Edited by sgiachetti on 09/26/2012 00:20:44 MDT.

If you have to ask you should be very cautious. A few points to consider:

First some 32 F bags are very optimistically rated others more realistically so. Not sure about yours but that brand is likely to be fairly rated if it is like my MH bag.

Second people are really different and we definitely can't say how you will be in a given bag.

I will say that my Mountain Hardware 45 is comfy for me down to freezing and with a thin layer down to the mid teens (in a bivy). That said I have camped with folks who were freezing in much warmer bags when I hadn't yet zipped mine. So my advice is to go conservative by at least taking more supplementary layers until you know what works for you.

Prepare for the SUCK.

The MH Ultralamina is cut efficiently (*tight), so strapping on extra goose feathers and merino skin suits isn't going to work so well, unless you enjoy all night fire vigils. I can totally relate to making what gear you have work, but taking a 32F bag (optimal condition, clean, and fully lofted) into conditions where any bit of condensation could spell trouble isn't wise IMO. But..... if you want to suffer a bit through the night and just get through it, go for it. Lowering your expectations will be necessary. In my experience, additional layering to meet a temperature or stretch a bags warmth when in below freezing temps just isn't the same as having an appropriately rated bag/quilt to begin with. This isn't so much the case when the temperatures are mild.

Good luck.

I used to do this regularly, and it seemed like normal winter sleeping to me at the time. I always slept with ALL clothing and hard shell on me to prepare me for the "normal" sleep/shiver winter experience, as I never got too warm :).
I was in my early twenties (high metabolism) and I only had one 0 C comfort rated sleeping bag and no money to buy a warmer bag or room to store it. I remember my hiking partners to have had even colder bags and they were miserable, but surprisingly, endured. They do have an aversion towards winter camping these days :).
I would avoid doing it again.

Edited by zorobabel on 09/27/2012 14:09:51 MDT.

Temperature Rating: 32° F / 0° C
Comfort Rating: 46° F / 8° C
Comfort Limit: 37° F / 3° C
Extreme: 12° F / -11° C

... note the extreme rating at 12F .... thats for women of course, but its likely close to 0 deg for men ... which means the average male would would be on the edge of hypothermia with the Ultralamina 32 at 0F ... and would likely lose toes ...

course you could add lotta down jackets, but that wouldnt be very weight or bulk efficient ...

I use a bag rated for the lowest "normal/average" temp expected. In shoulder seasons or mountains I take base layers top and bottom and a down inner jacket just in case. IMHO trying to get an extra 30 degrees out of bag would require to much extra weight and have no emergency tolerance if the temps dropped more than expected. If I expected zero temps I would take a zero rated bag with an R5 pad plus base layers which I suspect you will be wearing at that temp and my down inner jacket. For one trip rent if you can a zero degree bag or don't go. Good head wear might be a god send.

Yes, you would regret it. Especially in that bag that isn't a true 32* bag to begin with. I was on to of Mt Sterling (5800ft) one December and there was a guy up there in a Marmot Hydrogen (30*) and it got down to 9* that night. I was talking to him the next morning as he was huddled around the fire and he said he shivered all night and didn't sleep a wink. Will you survive? Probably, but it will be the most miserable night of your life. I don't think you would have the room to layer enough clothes to push it down to 0*. You might try and double bag and use a vaper barrier, but I would just buy or rent a 0* bag.

Also, don't forget a good sleeping pad. Many pads are not warm enough at 0*F.

It depends

I have bag that's maybe 40 degree F. Wear puffy vest, pants, booties down to 20 F.

Your bag has to be big enough so it doesn't compress inner insulation.

I need that insulation to stay warm before going to bed so it's the most weight efficient

Fleece or wool isn't very warm for the weight

Some perspective:
I have two bags that are very similar, Marmot's Arete and Pinnacle. The Arete is EN-rated to 42.6F, while the Pinnacle is EN-rated to 10F.
There's your 32F difference in temp between freezing and 0.
The Pinnacle uses 22.5oz of 800 fill down vs. 8.4oz for the Arete.
Almost triple the fill for a 32.6F lower EN rating, which is similar to what you're wanting to affect with additional layers.
I'm all for taking a bag below its ratings with clothing that would be carried anyway, but would be leery of trying to bridge that large of a gap in insulation value with baselayers and a jacket.

Here is a huge problem with doing what you are doing... loft. The more clothes you put on to help with the rating issue, the less loft you have available not only in your bag, but in your clothes too. If you can put on enough clothing to make up the 30 to 40 degree difference, after you are zipped up into an extremely tight bag, your rating on your bag/clothing just fell to who knows what.

I am in agreement with the rental at REI.

from the rating of the bag to what i can make comfortable if i am wearing everything i've brought with me. this includes putting your pack under your sleeping pad, or dubbling up your pad, and putting your pack under your feet or slipping your legs into your pack as an improvised bivy. If I’m going to supplement a sleeping bag with something that’s puffy (anything more than a down sweater), I tend to drape it over the sleeping bag as opposed to wearing it in the sleeping bag, unless it’s a fairly wide cut sleeping bag or any of the various elephant’s foot style bags that are designed to work that way. what's nice about a jacket/parka with a removable hood (ff volant) is you can drape the jacket over the sleeping bag to sleep and still wear the hood. some high-carb snacks and a hot water bottle go a long way to helping extend the range of your sleeping bag. don't forget a pee bottle. the last thing you want to do is let out all that hard won heat with a middle-of-the-night exit from your sleeping bag. i can push it lower, without being dangerous, but not being comfortable either. i've heard it said more than once (and it may have been said first by mark twight) that *if you aren't wearing everything your brought to sleep in, you've brought too much.* in this situation i'd borrower/rent a warmer bag.

If you're just doing this a night or two and don't mind carrying more weight and bulk, you could get a cheap/heavy/bulky/large synthetic sleeping to use as an overbag. This would add probably 4 or 5 lb and a lot of bulk. The xtherm pad might be good enough.

From Eric Chan's post of the EN ratings, I'd think this ultralamina 32 bag wouldn't be very comfortable even at 32F