-20 vs 0 degree Sleeping bags

Im shopping for a new down sleeping bag and don't know weather to get a 0 or -20. Im going to use it for backcountry skiing trips in the winter and early spring as well as climbing trips in the Cascades. So far, the lowest temp I've slept in was temperatures around 10 in my 20 bag. They say get a sleeping bag that is rated around 15 degrees colder than your intended use. So this brings my attention to a -20 bag. But i also only slept in those condition a couple times with my 20 bag and I was cold, but survived. The majority of the use of this bag would be summer mountaineering trips in the cascades like Rainier, Baker, and the North Cascades. This brings my attention to just a 0 bag.

So my question is would you rather have the security of a -20 bag even if you might only need that warmth once or twice a year, and be sleeping a little hot the rest of the year when temps are too cold for a 20 bag but not quite cold enough for a -20? Or would you just get a 0 bag and suck it up when the temps are around 0 degrees?

An important part of this equation is how hot you run naturally. The manufacturer rating is for the average male or female (guys run hotter so a men's 0 deg bag is not as warm as a women's 0 deg bag). Individuals can easily differ from this rating by a good 5-10 degrees. When you spent that night at 10 deg in a 20 deg bag, how did it feel? Adjust the manufacturers ratings accordingly.

All that said, buying a bag for the absolute worst case is a mistake IMHO. A better approach is to buy a bag for temps you really expect and then make sure that you have a bit of room to wear extra layers inside the bag if the worst case actually happens. You'll appreciate the weight and $$$ savings.

0 degree all you need if it's colder out you should have adequate outerwear with you to wear in the bag....

I forgot to add, Quality counts......

My Zero degree bag is a Feathered Friends.....

As said above at 0F bag will get you through most nights. If needed wear extra clothes - but not shells. The biggest help is wearing a hat to bed.

I have a 0 and -25 rated bag and the -25 is by far warmer than my 0. It might be due to the fact my 0 bag is the crappy French brand Quechua and I only bought it because I got a great deal on it. There has definitely been nights when the temperature was above 0 or hovering around 0 and I wished I packed my -25 instead of my 0 even with extra layers and a hat on.

Because I'm poor and hate carrying a heavy pack, my quiver of sleeping bags is one 15 down bag and one 40 synthetic bag. If it is really f'n cold I bring both, in 500+ days of sleeping on Alaska glaciers I've only used the two bags together a few times. A 15 bag + all my clothes + a warn nalgene bottle = staying warm in aprox -15 ambient air temperature. Check out the Mont Bell down bags and the cheap REI synthetic 40 bags. The Mont Bell bags have a lot of internal space, so they can accommodate the 40 bag. The synthetic bag inside the down bag is able to better dissipate moisture due to the temperature gradient and keep your down bag drier.

wfscot wrote:An important part of this equation is how hot you run naturally. The manufacturer rating is for the average male or female (guys run hotter so a men's 0 deg bag is not as warm as a women's 0 deg bag).

I have never purchased a top-of-the-line bag from a high-end company, but I find the temp ratings are quite overrated. I have slept in my car in a Mountain Hardware 15-degree bag when it was 40 degrees out and completely froze my ass off. Presently, I sleep in a 0-degree bag for nights down to 35 degrees, and it keeps me reasonably warm, but if it dips below freezing, my 0-degree bag wont keep me warm.

However, I use an inflatable mattress in my car as opposed to a real sleeping pad, which is probably part of my problem. Also, I live in Hawaii, so cold is not exactly my specialty.

read this to understand sleeping bag "ratings"

mammut.ch/images/Mammut_Sle…

also note that as explained in the document ... below -20C sleeping bag ratings may no longer be "accurate" due to various assumptions

;)

bearbreeder wrote:read this to understand sleeping bag "ratings" mammut.ch/images/Mammut_Sle… also note that as explained in the document ... below -20C sleeping bag ratings may no longer be "accurate" due to various assumptions ;)

I love how Mammut is not afraid to talk shit:

"Heavy or slim:
- Fat people often say that they have a slow metabolism. It is more accurate to say that they eat more than they burn up. "

hahaha

20 kN wrote:However, I use an inflatable mattress in my car as opposed to a real sleeping pad, which is probably part of my problem. Also, I live in Hawaii, so cold is not exactly my specialty.

^^^ This. For sub-zero temperatures, your sleeping pad will be critical, as your sleeping bag insulation is compressed under you. For your expected temperatures, your pad(s) should have a total R-value around 5-7.

If you're going to try comparing bag ratings, I suggest considering only the EN rated numbers (comfort or limit, but know the difference!). I have heard the ratings for Western Mountaineering bags are also trustworthy.

Personally I think the -20 bag is overkill.

Get a western mountaineering zero. At zero it's comfy, at 30 it's a sweat shop.

Thanks everyone for your input. Im going with a 0 bag.

Any suggestion?

I know Western Mountaineering and Feathered Friends make good bags but they are on the expensive side.
Any experience with Mont Bel or Marmot bags? Are they any good?

My marmot bag is only rated to 25, and it's synthetic, but I found it lost it's warmth after one or two seasons. Granted, I spent about 100 field days in it teaching for outward bound in Maine. My western mountaineering bag however, is like heaven on earth. I know they're pricey, but they're worth every penny. My fiancé's WM bag has lasted him a decade and it's still as warm as the day he bought it. My advice FWIW, buy quality gear and take care of it.

I have a 15* Down Mont Bell bag. It was a bit spendy, but its true to its rating (and I sleep cold), and so far seems to be holding up very well.

+1 for Montbell. UL super spiral down hugger. Great bags.

My 20F (feathered friends) has been plenty warm for the Cascades in winter. -20 would most definitely be overkill. Get a 0F, or even a 10F, and bring a super-warm pad or an extra closed-cell when you're worried about it.

I have the zero degree marmot lithium and it's awesome. I'm 6'1" and fit in their regular size bag. I also have the 15 degree lithium. I'm a gear addict...

What pad are you using? If you get one of the high R value thermarest inflatables and even pair it with their silver reflective solite (sp?) foam pads, it will make a huge difference.

If your intended purpose for the majority of the trips is pacific NW in summer, you could probably go with a solid 15 degree bag with a good pad; in my humble opinion.

Looking at retail prices, nearly any high fill-power (800+) down bag is going to be around $500 new. Down bags in the $250 range are usually lower fill-power (~600-650) and weigh a bit more; the increased weight may not be worth it, particular if a synthetic bag can be obtained for a similar weight.

I suggest keeping an eye out for people unloading quality bags; I saw some MH Phantom 0s earlier this year on BPL, and currently a 15 degree bag is available: Phantom 15

Nikita Cardenas wrote:Thanks everyone for your input. Im going with a 0 bag. Any suggestion? I know Western Mountaineering and Feathered Friends make good bags but they are on the expensive side. Any experience with Mont Bel or Marmot bags? Are they any good?

Marmot Lithium is a terrific bag. It is cut generously, so you can layer on extra clothing inside and push the temp rating even lower.

I love my Lithium. It's my go-to winter bag.

My wife has a zero degree down marmot and loves it. I have the synthetic Montbell and I'd say its comfy due to the stretch but at least 30 degrees colder than the WM.