Combo bags - 1+1 = 3???

[Desk Jockey]

Anyone using a combo bag system on the regular?

i was repacking my winter truck kit (I add a few winter items to my truck SHTF gear during the winter) and admiring the old USGI ECWCS sleeping bag I have in there. Two bags plus a bivy made for a versatile sleep system. it is too heavy for me to haul backpacking these days but it does just fine as an emergency bag and for occasional truck camping.

I also saw a neat system from the north face called the One bag. It is a lightly insulated bottom with two tops that zip in. One synthetic for *40. One down for 20* and combined for 5*. Seems neat.

I have added a quilt or woobie over my 20* bag for extra warmth a few times but not regularly enough to really know what what kind of temps would really be comfortable. I do like the idea of having a wearable glassing poncho that can be part of my sleep system and maybe replace a puffy jacket and or pants. I am tempted to go take my 20* bag and my mountain serape in the backyard and try it out.

anyone running a combo sleep system they really like? What temps do you feel comfortable in?

 

[Desk Jockey]

This is the northface set up. Seems to be getting interesting reviews.

Sleeping Bags for Camping & Expeditions | The North Face

For camping, backpacking, and expeditions, choose sleeping bags from The North Face. We offer a variety of styles including insulated down sleeping bags, bivy sacks, mummy bags, and more.

www.thenorthface.com

 

[Mountain_Life]

I use a 40° quilt down to about mid 30s, transition to a 15° mummy bag down to teens and then bring the quilt into the mummy bag for temps under that. I've slept comfortably into temps just below zero with this setup.

 

[MountainTracker]

This is the northface set up. Seems to be getting interesting reviews.

Sleeping Bags for Camping & Expeditions | The North Face

For camping, backpacking, and expeditions, choose sleeping bags from The North Face. We offer a variety of styles including insulated down sleeping bags, bivy sacks, mummy bags, and more.

www.thenorthface.com

Interesting for sure


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[thegrouse]

I have a 10 degree down quilt and 40 degree synthetic. I have not had to stack them yet, but I did see the chart EE has on their website with the ratings for stacking them.

 

[Rokwiia]

The formula I've always seen used to determine the net result of combining two bags is x – (70 – y)/2. x= lowest termperature rated bag and y the higher temperature bag. For example:

You have a 20F bag and combine it with a 40F bag. The combined rating is 5F calculated as follows:

20F - (70F-40F)/2 = ?

20F - (30F/2) = ?

20F - 15F = 5F

 

[Kevin_t]

I've experimented with two bag or quilt systems a lot . There are some benefits, especially for the backpack hunter in shoulder seasons .. but it will never win on the weight front. The formula stated above , in general more than works. In fact , my cold weather setup used to be putting a 20 degree quilt inside a 15 degree bag .. and i'v taken that comfortably to -8F (Neither of those bags were true to rating ). That setup , according to the rating , should have been a -10F rating. I have also comfortably taken two 20 Degree quilts to -25F in yard testing. So that rating I feel is "conservative" as long as you do not have compression.

Now the downsides to the approach are weight and a loss of breathability due to other layers .. and a bit of loss of simplicity. However, I do feel I could take my WM Terralite, and the WM quilt and get them close to 0 F .. which at 3 lbs is about like a WM Kodiak.

If this is done with a a synthetic layer on the outside, it does help act as a moisture mover by moving that temp a few degrees so an example of a 40 Degree synthetic quilt may move the temp 15 plus degrees of the interior bag rating helping to move moisture out of the down bag. The same quilt can be used during the day hunting when yo need warmth such as glassing etc. However, this is the heaviest option of the bunch .. for the weight stuffing a down quilt inside a down bag is lighter and the down quilt will NOT accumulate any residual moisture.

In the end, if I was on a budget and wanted good bags , I would go with a 2 bag system to save money and increase the versatility .. however my self, I'd probably go with the a down 30 Degree quilt and like a 20 degree bag and then combine them. I suspect combined they go to 0F and very possibly could be pushed to -20F.

For rating , there is the conservative formula mentioned above, but I also look at total loft , and if it is sized well so there is minimal compression, I think the total loft gives you a more likely rating. However, please note, for a bag half the loft (say 5 inch is 2.5 ) then use the quilt which maybe is 2.0 .. then go find a sleeping bag with a total of 9 inches of loft and that would be the stretch goal IMO .. and personally given the times I have used it and test I have ran ... I would guess is closer to real rating. However, a single bag will be drier and more breathable

 

[Trial153]

The thing that stops me is dealing with combining the two during dialy set ups... I also loving buying a using gear so the idea of have several...and I mean that several bags and quilts that I can pick and choose from based on conditions is more appealing

 

[thegrouse]

When I cowboy camp in my 10 degree down I get quite a bit of moisture build up on the outside. I have considered the 40 degree synthetic over the top, but I don't want to carry 2 quilts. I think that would be 48oz combined and too heavy and bulky