Using two sleeping bags

I happen to have two warmer weather sleeping bags-any serious problems with using the two of them together in colder weather? One is the Northface propel, and the other is the light patrol bag for my army modular sleeping system. Thanks.

It works well if both have enough room for their full loft.

I think what food is saying is that if they are close to the same size one may compress the other and therefore lose some of it's insulating value...sabre11004

Is there any way to get a rough idea of temp. rating, assuming full loft for both?

There are no standards for the temperature ratings on bags. Fit, features and loft all contribute to the comfort of the bag. A close fitting bag is warmer than a bag with a lot of extra room. A 20 degree bag has these features:

A hood,
Full collar - stops the bellows effect,
Draft tube - zippers cause a draft, and
Baffle construction - not sewn thru.

Bags degrade every time they are compressed. To measure the loft lay the top flat on the floor and allow it some time to fluff. Put a yard stick horizontally flat on top of the bag and push another yardstick vertically down next to it.


Comfort Rating in Degrees Fahrenheit Respective Loft Height in inches
40 1.5
30 2.0
20 2.5
10 3.25
0 4

I thank you for the information-I do have decent knowledge and moderate experience backpacking. I know that temp rating is a rough guide at best. I'm just trying to figure out (short of my back yard) roughly how cold I would be comfy using the two bags together. I've used them both individually, and was warm down to to about 45 degrees. The patrol bag is pretty big-it is designed to have a big 0 degree bag inside of it, so there should be no problem with the propel getting full loft.

My Marmot Helium, rated to 15 degrees, has no collar. I'm also not sure about "baffles vs. sewn-thru", as this bag purports to have "sewn-through baffles".

I haven't pushed the limits on this particular bag, but reports are good. I've pushed other Marmot bags, always with happy results.

Yep, all generalizations are wrong part of the time. Those are still the features that I tell people hunting for a 20 degree bag to look for.

Just as a note, I use a Coleman Fleece sleeping bag inside my 32 degree bag when it's below 40 degrees. It's light and seems to be a good option for adding warmth.

I also toss a "Hot Hands" in the bag about twenty minutes before getting in.

I am assuming you mean the green bag. Don't you have the black one? Those two are meant to fit together.

I have a bag that is at least 4" in loft but is rated at 20 degrees. What's up with that?? I did not realize that the bags were rated that way. That is very interesting. Does it work the same way for down bags and synthetic ones too?? I would be interested in knowing that. I have a western mountaineering bag and I also have a Marmot bag. They both work really well but the western mountaineering bag is the better quality bag in my opinion and is, although rated the same the warmer bag also...sabre11004...

They may work for temperature but you are basically adding extra weight of the nylon lining material and an extra zipper. I recall that the down is only about half or less of the total weight of the bag. So this is not really efficient.

W_D is correct--two separate bags will be quite a bit heavier than one warmer bag. Of course, using the two bags you already have will be lighter on your bank account. Only you can decide which is more important!

If, as you say, one bag will fit over the other without compressing the insulation, the combination may work. However, we all differ as to sleep styles and our individual body "thermostats." In other words, you'll need to test the combination yourself. I'd do the testing in the back yard (if cold enough) or car-camping before going out on a longer backpack. Be sure you have a nice warm pad (not a NeoAir!) underneath!

Yes, my regular super-cold weather rig is a down bag *inside* a larger synthetic bag (regtangular) You do need to make sure the outer sleeping bag doesn't compress the inner one.

It's definately not *lighter* than carrying one bag that is enough for your conditions though. I personaly use the above because

1) I'm too darn cheap[1] to fork out a grand for a nice WM puma.

2) For me, I do well with the above rig managing bag condensation in subzero temps.


As others have mentioned don't forget a warm pad - or two.. (I use an inflatable big agnes and one or two blue foamies.

[1] The kind of cheap that knows what it will cost me when the CFO finds out I spend a grand on the above bag..

Thank you, everyone. The Northface bag in question is zipperless, and very light and compact. The outer bag compacts pretty well. I like to read before crashing, so at the very least, I can use the inner bag while reading, with the outer as a pillow for elevation. Then, when I'm ready to sleep, I'll add the outer bag.

Finally me-still a bit unfamiliar with this forum-I thought I answered you, but maybe I didn't. Yes, I do realize the green bag goes with the black one, but I don't need that much warmth.

Yes-the green patrol bag-I understand they are meant to go together, but I don't need THAT much warmth and bulk.

The loft numbers are just a general guide when shopping for a bag. In my opinion the higher quality dow insulates better than down with more feathers. Also synthetic insulation may need less lost.

Back in my army days that was exactly the setup. We had two bags, an inner and an outer so that we could adapt to various temperatures. However, the inner bag was likely a little smaller so it fit nicely inside.

Howie

If you have a good insulating pad underneath (really important in cold weather!), you can use the second bag--if it has a full-length zipper--as a quilt over the top of the first bag. I would think this would tend to compress the insulation less.