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0F Sleeping Bags
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Petra S

Locale: Ohio
0F Sleeping Bags on 12/07/2013 13:19:03 MST Print View

I just tried out the Marmot Never Summer 0F sleeping bag. I also wanted to try the WM Kodiak but the store didn't have one. No problem, but it got me thinking about the difference between the 2 bags. What is the difference between a 600+ fill 0F bag and a 800 fill 0F bag? How can each be rated the same but be so different?! Even when looking at the Marmot bags, Never Summer and Lithium, there is a 150 fill and around a $200 difference but they are both rated as a 0F.

I've backpacked with my daughter's Girl Scout troop 6 years ago in the early fall. Now I am getting serious about backpacking and want to put together a quality pack but at a reasonable price. The sleeping bag will be my most important purchase. I am a side sleeper with one knee up and I sleep cold. My first trip will be in SE Ohio at the end of Jan and I do NOT want to be cold!!! Please I would like any kind of advice on just about anything, but sleeping bags are my priority right now.

Tipi Walter
(TipiWalter) - F
Best Bag on 12/07/2013 13:27:18 MST Print View

If you don't want to be cold I'd go ahead and invest in the best subzero bag you can find. All this is personal and subjective, but my 750 fill Marmot 0F Couloir bag stopped working for me at around 10F, so I upgraded to a -15F WM Puma and it keeps me alive (and comfy) right around zero and little bit below.

So, in effect, I'm saying to bump up all sleeping numbers 15 degrees and you'll get a better idea of its warmth for you. So, generally a 0F bag will work well to about 15F, etc. Also what's below you is vital. 5R value pad minimum for butt cold temps.

As far as 600 vs 800 fill, I'd always go with the 800 or 850 fill---it's a no brainer because it will be lighter and as warm as you can stand for the price you are willing to spend.

In addition, the amount of down inside a bag is the most vital number---along with the fill quality. A good winter bag generally has around 35 ozs of premium goose down---or more.

Billy Ray
(rosyfinch) - M

Locale: the mountains
Re: 0F Sleeping Bags on 12/07/2013 13:43:37 MST Print View


some things to keep in mind:
If you are a cold sleeper then you will need to go at least 10F colder rated bag than the ambient temps you expect to encounter.
Women tend to sleep colder than men and some of the bags are rated different temps for men and women.
Some bags are cut wider in the hip area for women. Depending on your shape you might want to consider that.
I roll around a lot and sleep on my side a lot. When that happens cold air gets sucked into the bag. So I find it great to wear the thin Montbell down pants and jacket into the bag. In addition to protecting against those cold drafts being sucked into the bag, the thin down suit is great for getting up during the night and first thing in the morning. The cut of the bag needs to be wide enough to accommodate the clothing you might want to wear in the bag without compressing the down.
Some bags have more room inside than others. Generally, a slimmer cut bag will be warmer since there is less air for you to heat up. But slimmer may not be as comfortable... it's a trade-off. But if you are thin, I recommend you look for a bag that is cut slimmer... it will be warmer even if it has the same rating as a wider cut bag.
Unfortunately, most of the bags are cut on the wide side as the makers calculate that more people can fit into them than a thinner cut bag.
Go with at least 800 fill down. The quality bags will have at least 800 fill.
Also consider Feathered Friends bags... some of them are cut more slim than other makers.


David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
bag fill on 12/07/2013 16:06:40 MST Print View

Down fill is the volume a given weight of down takes up. The higher the fill number, the more air the down traps for a given amount, and thus the warmer it keeps you.

If you anticipate doing a lot of backpacking, a top tier bag with 800+ fill is a worthwhile investment. Women generally do well being conservative with their sleeping bag ratings. Second and third rate sleeping bag makers (Marmot, REI, etc) generally don't do as good a job meeting the warmth ratings they give their bags, when compared to the best (i.e Western Mountaineering).

Buying a WM bag rated around 5-10 degrees colder than your expected low temp is a good, conservative choice.

eric chan
(bearbreeder) - F
Re: 0F Sleeping Bags on 12/07/2013 16:27:23 MST Print View

Read this from end to end

Then go an find a bag that is accurately rated and then get one that is another 10F "warmer" (ie a -10F bag if you need 0F)

Note thet below 0F is when en ratings are no longer accurate due to the reasons explained in the document

For temps above that the ratings are relatively accurate BETWEEN bags as a comparison ...

Remeber though they are for a mid 20s female in good physical health for the "comfort" rating ... Amd it assumes a pad value of R5 or so

As to "top brands" ... It doesnt matter what the name is if the bag doesnt score well on the en ratings it wont magically warm up due to the brand name

A simple search on BPL will show cases of the WM summerlite which is rated 32F, tested at 35F lower limit where some BPLers felt cold

Insulation is insulation .... Most REI and Marmot bags are now en rated


Lapsley Hope
All good advice on 12/07/2013 16:39:59 MST Print View

everyone has posted good advice. When it comes to brands though I am very partial to Feathered Friends and Western Mountaineering.

John H
(pastyj) - F

Locale: SE US
Re: 0F Sleeping Bags on 12/07/2013 16:55:23 MST Print View

I would not characterize Marmot as a "second or third rate sleeping bag manufacturer" :)

The previous posters have covered all the points:
1. Get a bag rated BELOW your expected low temp...or
2. Make certain the bag is roomy enough to comfortably accommodate you wearing your insulation layer. Satisfying BOTH these requirements is the safest decision.
3. Buy the highest quality down and bag you can afford. Well cared for, a quality down bag will last 15-20 exaggeration.

My personal experience is that Western Mountaineering makes the best bag...for ME. I recommend that brand to those who ask, however I have (smaller) friends with Marmot bags who love them as much as I do my WM.

Finally, There are many quality brands (Feathered Friends, Mammut, etc etc etc) that I have no experience with. Since a good bag will run upwards of $500, take your time and do whatever is necessary to see, touch and climb inside several different brands and models. Like most things in life, you will know the right one for you when you see it.

Dustin Short
(upalachango) - MLife
Re: Re: 0F Sleeping Bags on 12/07/2013 18:22:50 MST Print View

For women, I definitely recommend looking at a Feathered Friends bag. They're women's versions seem well designed and cut more than others that rely on a unisex (*cough* male *cough*) shape or a poor female cut.

Also do NOT discount the warmth of a sleeping pad. I thought I used to sleep cold and needed a burly sleeping bag but once I upgraded my sleep pad to something warmer, I realize I sleep hot! You'll lose more heat to the ground than you will the air in most situations. Invest in a good and warm sleeping pad (like a women's neoair with a CCF under it or any down mat). It's pricey but comfortable sleep is the one thing I find that makes up for any and all other discomforts of hitting the trail.

Joe Lynch
(rushfan) - MLife

Locale: Northern California
consider montbell on 12/07/2013 22:53:29 MST Print View

If you move a lot while sleeping, take a look at Montbell sleeping bags. They are designed to have some give and are very comfortable for side sleepers.

Rick M
(rmjapan) - F

Locale: London, UK
Re: consider montbell on 12/08/2013 01:02:59 MST Print View


Edited by rmjapan on 06/20/2015 10:08:32 MDT.

Bradford Rogers
(Mocs123) - MLife

Locale: Southeast Tennessee
Re: 0F Sleeping Bags on 12/08/2013 07:16:46 MST Print View

If you really expect 0* temperatures and sleep cold (or are a female) then tipi is right, buy a bag 15*-20* warmer then you need. You also need to realize that a warm bag does you little good if you have an insufficient sleeping pad. For those temps you need something that has an R value of at least 5. You can get that from 1 pad like the Thermarest NeoTherm or the Exped Downmat UL7, or you can stack pads like a Thermarest Prolite Plus and a Ridgerest.

Most sleeping bag manufactures rate their bags (even women's bags) for a fit, young male. As you get older you tend to sleep colder, and women tend to sleep a bit colder then men.

You also want to make sure that you get a bag that has the right shoulder girth. The Kodiak, that you mentioned is a HUGE bag and if you are of slight stature, all that space will take forever to heat up.

I am a big fan of Western Mountaineering bags, but Feathered Friends, and the top bags from Marmot and Mountain Hardwear are pretty good too. Mont-Bell bags are interesting as well. I have never used a Mont-Bell bag, but I have used a lot of their down gear with excellent results. If you are looking for a deal, Golite has a -10* rated bag that is only $399.

Then you also need to realize that a sleeping bag this warm will absolutely roast you in summer, so you will probably need at least 1 more bag for year round backpacking.

Backpacking at or near 0*F is no laughing matter, those are serious temperatures that require serious knowledge and specialized (and expensive) gear. Make sure you are safe and have fun.

Petra S

Locale: Ohio
0F Bags on 12/11/2013 22:17:48 MST Print View

Thanks for all your advice! I'm picking a 0F bag because I do not want to ever sleep in weather that cold. That said, I am still confused.

Is there an actual temp difference between a 650 fill and an 800 fill bag or is is just mass and quality. I will put the money out for an 800 fill bag if it means that it will last me for the next 20-25 years but I still want to know if a 650 bag will keep me just as warm as an 800 bag.

My next problem is that I'm in northern Ohio. There are not many places to buy bags and I do want to 'try them on' before I buy. Does anyone have any idea where I can find a store or outlet where I can actually look at samples?

Again , thanks for your help.

Dustin Short
(upalachango) - MLife
Re: 0F Bags on 12/11/2013 22:31:44 MST Print View

Fill power is simply a measure of the quality of down. Specifically it's the volume of space that an ounce of down occupies after being weighted. So a higher fill power (say 800+ vs 650) will require less down to insulate. That basically translates that for a given accurate temp rating, a higher fill power bag should be lighter than a lower fill power bag. Other factors come in too such as fabric choice and actual fit/size of the bag. Find a bag that is EN rated or else trust Feathered Friends or Western Mountaineering ratings (they've been making premium quality bags for quite a long time).

Slugsworth .
contrarian on 12/11/2013 23:02:35 MST Print View

As the last poster said 650 vs. 800 is just the quality of the down, the 650 will feel heavier and be slightly less warm. That can be made up for by having more down in the bag.

I like winter camping but don't do too much, my winter bag is 650, it was cheap and gets used but I would prefer to put my money in other places and in gear that gets used on more trips.

The question on whether to get 650vs 800 down really has to do with how much you are willing to spend too save x amount of weight (& bulk) when using that bag. If you will be camping mostly in 3 seasons it may not make sense to spend much on a winter bag.

Edited by slugsworth on 12/11/2013 23:04:10 MST.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: contrarian on 12/11/2013 23:10:04 MST Print View

yeah, it's just a matter of paying a little more to save a few ounces

and someone (Ryan?) said that lower fill power loses it's loft less when it gets damp

Rob P
(rpjr) - M
Place to try sleeping bags on 12/12/2013 10:38:42 MST Print View


I saw that you are in northern Ohio…I don't know if you are near the Toledo area, but Toledo is very close to Ann Arbor.

Bivouac in Ann Arbor has a lot of Western Mountaineering and Marmot bags among others in stock that you can try.

Also, regarding Western Mountaineering, they have several bags that are at or near the 0 degree temperature rating that all have different cuts…The Sequioa is semi rectangular, the Kodiak is a wide mummy, and the Antelope is a narrower mummy. Their weights and pack sizes differ slightly as well.

Even if they don't have the particular bag you are interested in, you can try on a bag with similar dimensions to get an idea for fit.

Print out the WM mountaineering catalog and take it with you to the store, since the dimensions of each bag are listed.

Edited by rpjr on 12/12/2013 12:11:40 MST.

Sumi Wada
(DetroitTigerFan) - F

Locale: Ann Arbor
Re: 0F Bags on 12/12/2013 11:12:45 MST Print View

>> Is there an actual temp difference between a 650 fill and an 800 fill bag or is is just mass and quality. I will put the money out for an 800 fill bag if it means that it will last me for the next 20-25 years but I still want to know if a 650 bag will keep me just as warm as an 800 bag.

The fill power or fill count is a measure of volume per ounce of down. "650" means that an ounce of that down will fill ( to) 650 cubic inches. "800" obviously means 800 cubic inches per ounce. So, a higher fill count down requires less down for the same loft, which will make the sleeping bag lighter for the same temperature rating since the rating is directly related to loft.

An accurately rated 0-degree will perform the same, whether it's 650 fill or 800 fill. The difference will be in the weight and volume and, consequently, the price.

Dena Kelley

Locale: Eagle River, Alaska
"0F Sleeping Bags" on 12/12/2013 11:25:39 MST Print View

I agree with what Tipi said about getting a bag rated for colder than the temp you expect. I always take a bag rated for 20 degrees colder (at least) than the lowest temperature I expect, because I'm a cold sleeper and because I think bag manufacturers are often optimistic on bag ratings. I've also begun buying better quality bags- my most recent two bags are a WM Puma, and a WM Versalite.

800+ fill is nice because it compacts better.

As a cold sleeper here are my suggestions for staying warm at night:
Wear socks or down booties, and a balaclava.
Take a hot water bottle or two (well sealed) into your sack with you at night.
Wear long johns.
If you use an air mattress, consider topping it with a CCF pad. Air mattresses conduct the cold.
Eat a high fat snack immediately before bed.
Pee before bed.

Michael Marinelli
(ChairmanMallard) - F

Locale: SF Bay Area
Sleep Pad on 12/12/2013 11:54:10 MST Print View

The XTherm was the best investment I made for sleeping. I haven't had a single cold night since I bought it. Granted I've only been down to about 30 F and I also have a RevX rated to 20 F.

Andy F
(AndyF) - M

Locale: Midwest/Midatlantic
Re: 0F Bags on 12/12/2013 12:29:54 MST Print View


A 0F 650 fill bag will keep you as warm as an 800 fill bag. The difference is just in weight and feel of the bag. An 800 bag will be maybe a pound lighter, and it will compress easier and smaller into your pack.

Another thing to consider is that 650 fill down is actually a little more resistant to the effects of moisture, such as from humidity in the air and perspiration from the body while sleeping.

I have a 0F Marmot Never Summer 650 down bag. It's 4 pounds, but it works great, especially for the price. I've used it overnight many times, as low as around 5-9F, and tested it for a few hours in the backyard at 0F. Locations were Ohio, UP of Michigan, and the mountain wilderness areas in West Virginia.

I use it with an Exped DownMat 7. I use the heavier version which weighs almost 2 pounds because I don't want a puncture to take out my ground insulation at temps that cold.