Stretching a 3 season quilt into winter camping

if you needed all of the above insulating clothing to get you comfortable at the quilt's rating (20 degrees), then you can probably push it a little more w/ down pants and a medium-ish down parka, but not a heck of lot more imo

down booties will help (as well as being very nice in camp), a balaclava combined w/ a good down hood (from your parka) should help as well

not sure what temps you need to get down to, but if it's anything lower than 10 I'd consider opting for a different quilt or bag

We can refer to Richard's clo chart in garment warmth thread to get the amount of required insulation at certain temp. First, specify the lowest expected temp. Second, check whether your layering meets the clo needed for relaxed activities at that temp. Finally, check whether all of the layering + quilt and pad meets the clo needed for sleeping at that temp.

My quilt from BillyGoat/Virga Outdoors has 7.6oz of 900fp down and it's designed to be good to 35-40F.

Wearing a light baselayer top, hiking pants and hiking socks, I do an honest 35-40F and be warm.

Adding my Montbell Ex-Light vest (~1.7oz of 900 FP down) takes me to just above freezing…about 33-34F

In the colder months, I leave the Ex-Light at home and go with:
– MB Alpine Light Parka (~4oz of 800 FP down)
– GooseFeet Down Pants (~3oz of 800 FP down)
– Ideally GooseFeet Down Socks (~1.5oz of 900 FP Down) – Don't own, but I steal my wife's.

With all that clothing effectively doubling the amount of down I'm wearing, I'm good to about 20-24F when sleeping on an R-3 pad (Exped Synmat UL). That's sleeping on a wooden bunk. I'd probably need an R5 pad like yours if I was directly on the snow but maybe not.

This 15F stretch seems about the most that's possible. With the Alpine Light Parka the quilt is barely wide enough, so if it was colder than this I'd need even more layers and drafts would be even more problematic, so I'd probably just steal my wife's bag which has double the down to start with, and then layer from there.

For you, consider what temps you'd actually sleep well in, wearing just base layers in your quilt. I'm guessing with head to toe down you could add up to 15F to that temp. How much down is in your quilt? It sounds like your quilt is a bit optimistically rated.

Unfortunately, adding clothing doesn't help as much as it should on paper. By that I mean that 10oz of down clothing isn't nearly as effective as 10oz of down to your bag/quilt.

Why is that?

Are you saying it's because 10oz of down clothing actually only contains about 5oz of down? Or are you saying 10oz of down in a sleeping bag is more effective than 10oz of down in clothing?

The latter, Dan. I don't have a good explanation, it seems to me a bit of paradox but true by experience.

My 30º quilt has ~9oz of down in it; my 0º quilt ~20. Even with a down jacket, pants, booties, and mitts, the 30º doesn't come close.

Clothing only takes you so far. Remember you don't want to compress the down from the inside by wearing bulking clothes that push on the quilt.

The pad is very important, I can feel the heat going out my synmat UL when its very cold.

I sometimes wear a down vest inside my sleeping bag.

I roll around in my sleep. The vest gets compressed underneath me, then when I roll onto my other side I never fluff it up so it stays compressed – it still works but not as good as it would be if properly fluffed.

When I wear a synthetic vest, it doesn't have this problem, it regains it's loft without being fluffed up.

I second the pad. I've found for me taking a warmer pad usually lets me get by with previously considered poor insulation. For example I've frozen in a 10F down bag at 40F on a thermarest prolite (in fairness it had a slow leak and eventually deflated) but have slept all night on two ridgerests in 30F at elevation weather wearing 100wt fleece pants and 300wt jacket…

Quilts are a tough situation. They are, by design, drafty and when temps drop below freezing (definitely less than 20F) that draftiness becomes much more of an issue. Wearing thicker clothing on the inside only exacerbates the issue, more so if you already fill out the quilt already.

"Specifically, I am interested in your experience using warm layers for winter camping. What works for you."

I love winter camping, but being a humble grad student, can't spring the dough for a winter bag. This has not hindered me at all, however–infact I am going out on an overnighter this weekend.

The coldest I have slept out in was -15C (5F), which was last year, and that was before I owned a down sleeping bag. For that night I cut pine boughs for my first layer of ground cover, then a space blanket on top, then my Big Agnes insulated air core pad. I won't even bother to list my layers, as they are heavy stuff, but are cheap and effective. I own no down clothing, and rely only on wool and synthetics.

Went out twice last month, one night was -2C (28F) and the other was -6C (21F). The difference is that I finally got a 3 season down bag, so to save big on weight and also to take less layers, what I did was use two sleeping bags. I have a summer synthetic bag that I use as a liner for my down bag, and on both nights was able to sleep quite well, and on a pad with an R value of 3 rather than my Big Agnes, which has an R value of 4. I plan on doing the same thing, using two bags, this weekend, and temps are supposed to be between -3 and -5 C.

So if you have another sleeping bag to use inside or outside of your quilt, that might save you weight. My summer bag only weighs 476g with stuff sack, which is less weight for me than taking say another pair of wool socks and an extra sweater in my pack, plus I can wear a lighter jacket too. I should also add that my down bag is only rated to 4 degrees C (39F).

I once stretched a my TNF Nebula 15F bag to -30F. I did this by using a cheap fleece sleeping bag from walmart as a liner, and i wore capaline 2 long johns and heavy polypro pants, capaline 3 top, wool sweater, and nano puff pullover, balaclava, beanie, and hood from an old jacket, glove liners.

I used a ECWCS goretex bivy as well. Inside of a shelter.

I also put two hand warmers in my pockets and used the hot water in a nalgene trick.

I was comfy, wouldn't make a habit of it, but comfy.