Down or Fiber-fil

I’m planning to get a sleeping bag for 30 degree nights when I camp on the islands of Maine. I realize the pros/cons of both fills. What is your experience?

Either is good…
…for 30 degree nights, but we have the synthetic just for the fact that you never know when you might get the down one wet, which will make it useless.



have had both
like the holofil for fact dampness can creep into down. especially with diffrent temps w/ humidity. They both will keep ya warm ,but IMHO holofil or similar fiber is better. I have been camping for the last 17 years year round and not in a pop up camper.

Tent or tarp?
Personally, I prefer down. A cold, wet synthetic-fill bag is not going to be all that cozy, either. The increasesd compressibility and reduced weight of down make it my choice. In my opinion, if things have gotten to point where your sleeping bag has gotten wet (I am not talking damp on the outside from dew/condensation) then you are having a bad trip. I use a down bag (North Face) and have for 24 years (not the same one; they have a usable life of about 10 years before they start to lose their ability to loft repeatedly). On water trips i put it in its own river bag. I use a tarp so I do not have a problem with condensation as I sleep. As either one will d the job, it really comes down (pardon the pun) to a matter of personal preference.

If the trip is long and you may have
weeks of thick maine fog I’d go synthetic. Down is nice and lasts longer but it might get boggy with fog.

Fiber for warm nights like 30
The advantage of fiber-fill that always strikes home for me was the times I got both types wet. One trip my oldest bag, my down bag got wet and the time I got my new fiber bag wet. The fiber bag was dry by the next evening. The down bag dried out a couple of years later (exaggerated for emphasis)(grin).

seattle sports
makes a compression dry bag. My down bag winds up about the size of a football. We played kayak dodgeball with it last weekend to test it out in the water on Casco Bay.

Dont go too low on the temp ratings, if you have a twenty degree bag you will roast.The temp now on the islands goes down to 35 at night and usually about 55 in the summer; its the water that never gets very warm(hence the fog)

Synthetics are supposedly warmer when wet since they dont lose their insulating qualities, but I still find damp fleece cold and prefer wool and never liked the sheer bulk of a synthetic sleeping bag.

Loft Life
I canoe, kayak, and backpack camp. I own multiple down and synthetic bags. I measure the total loft a new sleeping bag when I purchase it. A typical 3 season bag, using either down or synthetic fill, starts off with about 5.5 inches of total loft. I use a compression sack to achieve the smallest size for carrying while on a trip but the bags are not compressed for storage. After 2-3 seasons every synthetic bag has been reduced to an average loft of 3". My down bags have no reduction in loft. A 2" drop in loft equates to a reduction in the comfort of about 20 degrees. As a result of the synthetics low loft life span I prefer down for general use and the synthetic only for trips when I expect rain most days. By using a dry sack neither bag type has ever gotten wet from being dunked.

Never had a problem with…
down. Used to use only syn. bags ‘cause I was doing a lot of BWCA trips and feared gettin’ a down bag wet. After years of trips, I realized I never did get a bag wet, so I tried down. Never regretted the choice. My down bags have been climbing, paddling, camping with me for about 7 years now and I’ve got no intention of buying anything else. If you do decide on down, look at some of Marmot’s stuff. I’m not sure how much research you’ve done so far, but not all down is created equally. Get the best you can afford, and figure in the cost of a good dry bag too. I’ve used an OR dry bag on both canoe and kayak trips and never had a drop get past the closure. Happy shoppin’…

I use a wiggys bag, it’s a synthetic bag that replaced the US mil down bags, its lighter, warmer, and keeps its loft, and repels water. and you can get it in different sizes, and big + if you are big, tall, small or big and tall…

my experience with down
has been good, but I only use it for much colder winter trips backpacking in Michigan. I bought a 0 degree marmot 800 fill bag. I love it, it is a real comfort knowing I can get in that bag.

That said. Maine and 30 degrees is pretty cool too. Alot of people are going to say what if it gets wet. Well down doesn’t instantly loose all of it’s insulation just because it gets wet. Also how often has your bag really gotten wet at all. Probably never, because everyone, (at least I am) really careful with my bag. I keep it in a hydroseal stuff sack, and in a drybag when I go on a trip. So do consider down, it’s loft to weight and packability is worth it in my opinion. I have a cheapo NF bag that I do like. But when it’s loft is of no use anymore, I will probably replace it with a Marmot down bag of the same temperature rating.

I Use Down
I take precautions to keep it dry, and love the feel of it. As mentioned, down will loose it’s loft after years of use, even WITH proper cleaning and handling. I have a bag I bought in '77 or '78 (North Face Superlight) that was rated for 5 degrees when new. It gets chilly now when the temp dips into the low 40’s. If I expected the bag to get wet, I’d go with synthetic. My preference, is down. BTW, I can get the wife and I’s down bags, BOTH of them, in a small stuff sack the size of a loaf of bread. WW

Best to avoid compression stuff
sacks unless you need to use them. I totally agree compression stuff sacks mangle synthetic bags. Polargaurd hv or even more recent iterations have reasonable sutff sizes. Hollofill is a frugal choice but packs huge.

do you release the compression straps on your bag when not in use(storing)?Just got a synthetic similar to mil. ECWS bag . Had a down bag but it got too damp winter camping by the 2nd night due to breathing or body sweating.

tarp if its really bad
tent if the kids are along.

Sleeping Bag Storage & Pad Thickness
When not in use my bags (both down and synthetic) are stored in very large hanging bags without any compression.

Try a little experiment and measure the loft of any synthetic bag you have used for a few seasons. Next go to a store where the bags are sold and measure a new one. I suspect that you will be shocked by what you see. None of the synthetic bag insulations can handle compression cycles from compression sacks without breaking down quickly.

If the down bag losses loft during the night do to moisture from your body, you need to ventilate to eliminate any sensible sweating. Insensible moisture transport can be effectively eliminated in cold weather camping by the addition of a vapor barrier.

It is also important to match the pad R value to the minimum temperature that you are going to be sleeping in. Down insulation compresses more under your body that synthetics do.

Thermarest model Thickness R value Min temp

Ultralight 3/4 1 2.6 40

Ultralight Long 1 2.6 40

Fushion 1.25 3.5 35

Fushion EX 1.25 3.5 35

Guidelight Long 1.5 3.8 20

Camplight 3/4 1.6 4.1 15

LE 3/4 2 4.1 0

LE Long 2 4.1 0

Explorer 3/4 1.5 4.7 -3

LE Camprest 2.5 5.1 -5

Standard Long 1.75 5.8 -8

Base Camp 2 6.1 -11

Camp Rest Long 2.25 7.3 -15

Megarest 2.5 7.5 -20

Warmth = Thickness
With the exception of Thinsulate (1.4 better but doesn’t compress) all other sleeping bag insulation types including down, Hollofill, Polarguard Delta, ect have a similar R value. They rely on the insulation of dead air spaces and the minimum comfort range is determined by the thickness. As an example 2" of fine steel wool provides the same dead air space insulation value as 2" of Hollowfill.

To measure a bag’s minimum termperature rating for a theorectical average, zip up the sleeping bag and fluff it to acheive maximum loft. Next put a ruler along the side of the sleeping bag. Measure the total loft and then divide in half to determine the top loft. The bottom loft is compressed when you are in the bag and you primarily rely on your pad for bottom insulation. 1" - 60 degrees, 1.5" - 40 degrees, 2" - 25 degrees, 2.5" - 15 degrees, 3" - 5 degrees, 3.5" - minus 2 degrees, 4" - minus 10 degrees.

Either are good, but depends on you.
I love Down, but, I have an LL Bean Synthetic that I picked up new for a steal. Bought it for a spare bag around the house, and has become #1.

Wicks away moisture, keeps its loft even when wet, zippers work flawlessly and the warranty on em are great. No questions asked. How can you beat that? Only compromise is compressibility. Large sacrifice if backpacking, small sacrifice if paddling.

Have spent many 0 degree nights out in much comfort.

Hope you find the right one for you.


hey check out that site, it has great info on bags in general.

Another persprective
I read all the posts associated with down vs. fiberfil. I do 19th century camping and canoing. We use exclusively wool for bedding. It keeps you warm even if wet. Dries fairly quickly as well. It does weigh more than the others, but as a historical re-enactor, I live with that. As for shelters, I use either a 7x7’ canvas wedge tent or an oil cloth depending on conditions and time of year. I am new to this board and hope to share some of our experiences with you in the future. Our big trip this year is 65 miles on the Missouri River, ending up at Fort Union near the confluence of the Missouri and Yellowstone Rivers. Fort Union was a major fur trading post in the 1820-1830’s.

Kind Regards,

Dennis K. aka Sticher

southern Idaho