Sleeping bag size question

All other parameters being equal, I personally would check out the inner volume and girth of the two bags.  The bag with more internal space will be harder for you to keep warm in since it is the human body that warms you up not the bag or the pad.

The bag and the pad just slow heat loss through conduction, radiation, respiration, etc.  On really cold nights, you could fill up the dead air space (if there is any) by wearing a puffy sweater or other clothes.

How do you like the girth of your current bag?  If the Puffin is just the right girth for your style of sleeping while backpacking, it would seem the right choice.

I am 6 feet 1/2 inch tall and have used name brand 6′ and 6′ 6″ bags including FF and WM.  Personally, I don’t notice a huge difference in warmth having the extra length,  even when hanging off a 6 foot pad and I don’t notice a cold spot at the foot,  but I don’t wiggle around a lot either and I have warm feet not cold feet.  Then again, I never deliberately ran the experiment so I may simply not remember.  I also tend to pileup stuff at the foot of my bag to keep my bag from rubbing against tent or tarp wall – that WILL cool the feet due to compression of the down,  even if the bag doesn’t get damp. I look forward to hearing what others have to say.   I find that the six foot version of the  FF and WM are PLENTY long enough for me provided that I don’t intend to put boots or something in the foot of my sleeping bag.  In fact,I much prefer my 6 foot bags because they are less likely to get wet from rubbing up against a dew covered tent or tarp.  And THAT would definitely make the bag less warm.   If warmth is a concern – my personal experience, with the small sample of bags I have – WM is warmer and better made than FF. Not a lot of difference, but enough so that I prefer WM.  I strongly prefer my 6 bags as long as I don’t need to stuff things at the foot of the bag.

Idea – a number of outdoor sites have sales right now.  REI has a one item 20% off sale for members and many other retailers mimic the REI sale periods.  I think I’ve seen Campsaver, Backcountry and others with sale notices.   I bought a 20 degree rated WM from campsaver for 2021 Christmas at a good discount (may have been Black Friday).  I was shocked that something like that was on sale at a period of apparent Covid induced low supply.

Good suggestion by Bruce – put a sweater in the foot of the bag.  Wider bags definitely not as warm, but some people hate narrow bags.

Very helpful, thanks!

My current bag measures 61″ 58″ 53″.  The Puffin is 64″ 61″ 48″.  I like the dimensions of the Puffin, especially in the shoulders and the hips.  For reference, I have broad shoulders, and a slight beer belly.  I am basically 6′ and my weight fluctuates between 170 and 180 lbs.  I am a back and a side sleeper, and have found the Nemo bag to be quite tight around my shoulders.

I do plan to take the bag down around 0 degrees.  I currently take my Nemo bag down to that temp and have been warm and cozy.  I do use a WM Everlite as an overbag, and my STS Comfort Plus pad has an R-Value of 5.  I will take my foam pad with an R vaule of 2 if I am concerned about running cold.  I wear FF down booties as well.

I am only in this situation due to the availability of the bags I want.  The longer Puffin is the only one available at the moment.  It weighs 12 ozs more than my current bag, so a bit of a weight penalty there.  I dont sleep very well even in a normal bed, so I tend to go for comfort when sleeping outside, and made weight savings in other areas to make up for it.

Also just for fun, I sleep in an BA Copper Spur HV UL 2 mostly, but will use my Yama Mountain Gear 1P Bug Bivy with a 12 ft Dyneema Hex Tarp if I am not expecting the weather to be too crazy.  I will use my old REI Quarter Dome 1 tent from time to time too.  But its tight in there even with my 6′ pad.

If I were you, I would lie in your current bag with your usual sleeping clothes and ask yourself, is three inches enough extra girth?   ….with the caveat that too much girth can make for a colder bag even with the same EN temperature rating.

Brue,

How many degrees are we talking about with the extra girth, rough estimate?  The Puffin has a smaller footbox by 5 inches, though its larger in the shoulder and hips. My feet are the only part of my body that would get cold.  Even in the Nemo bag, this happens, but is not common.

If the temps are forcasted to dip below 20, I take my Montbell Alpline Light down jacket instead of my Ghost Whisperer.  I usually sleep in a R1 Air.  If its closer to zero, I wear the Alpine Light jacket and my upper body is warm, but its a super tight fit in there.  Tight to the point where I wonder if I am compressing the down (I stay warm though!).

Also, I know temp ratings are highly indivualized, but the Nemo Sonics comfort rating is 27 degrees.  I would imagine that the Puffin is a true 20 degree bag.  I have taken the Nemo bag down to 0 degrees and have been cozy.  I do use an overbag and a high R value pad with it.

@ Matt I think it depends on the bag and how you sleep. Perhaps 5 degrees?

Sounds like you need more girth to be comfortable.  If needed on cold nights, you could just wear to bed the puffy jacket you cooked dinner in.

Thanks Bruce, you nailed it!

As if fate would have it, the Puffin YF bag sold out this afternoon.  Looks like I will have to wait this one out.

Well if you wait long enough, everything you might want comes on sale eventually….

Some of the smaller on-line vendors like Everest Gear and BackcountryGear carry down bag brands that might be worth considering like Western Mountaineering and Rab.

@Bruce  The Swift UL came back in stock today and I picked one up. I spoke to FF (very responsive and helpful).  That was the bag I orginially wanted.  Hopefully the smaller footbox does not bother me.  Thanks again for the help!  This saved 3 oz from my current  bag, and saved 12 had I went with the Puffin.

Matt

Good to know.  Nothing more important than a good nights sleep while in the backcountry!

@Bruce  Agreed! Also, you called it, I just checked the Everest site, and now I wonder if should have gotten the WM Terra Lite in addition to the  WM Kodiak.  My fiance bought the FF bag for me for my birthday, so I could have gotten the Terra Lite for a nice discount!

I don’t see a chest collar on the Terra Lite, not a big fan of that omission, and would not work as my normal 3 season bag.  Full zipper could be nice for the spring and fall days in Virginia when it can be 60 degrees one night, and 30 the next.

@ Matt K

You might be over thinking the problem. 80% of the time I just use my Mountain Laurel Designs Spirit 38 quilt and just alter what clothes I wear under it for various conditions.  Get out there and use the FF bag a few times. If you don’t like it you can sell it on gear swap.

Cheers.