Confused about sleeping bag temp ratings...

[OhioHiker]

I have a Sea to Summit TKII bag it says Comfort rating 30, Lower limit 18, extreme -13.

I am thinking about switching to a quilt for 3 season camping. I am unsure what the one temp of my bag is? Is it a 30* bag or a 20* bag?

I ask because it is slightly hot for me. And my MH Lamina 45* (which reviewers claim it’s more like 50) is slightly to cool.

If I go quilt should I stay with the warmer bag and vent it or stick a leg out? Better to have and not need them need and not have?

[Slo-go'en]

Usually the low limit is what they claim for a rating. So in your case, it would be rated a 20 degree bag, I would consider 10F as extreme.

It's always better to have too much then too little when it comes to a sleeping bag.

[scope]

Depends, do you want to be comfortable? If so, then it’s a 30 degree bag. Most of the makes that do that sort of rating tier thing are not the most reliable ones. They’re typically trying to make you think it’s more like a 20 bag. But your make might be taking into account a cold sleeper being comfy at thirty, so perhaps you’re a warm sleeper?

Personally, I would assign the following real world rating nomenclature to supplement what the mfr means by their rating...

Comfort - what the bag should be minimally rated at, but read on because we want to sell more bags,
Lower limit - the limit that this bag will allow you to consider going camping again
Extreme - most likely survivable, though we make no guarantees about keeping all your digits


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[Franco]

From S2S
Comfort The temperature at which a standard woman can expect to sleep comfortably in a relaxed position. If you are female or consider yourself a cold sleeper, use this rating to decide the coldest temperature the sleeping bag is suitable for. We emphasise the Comfort temperature for our women’s specific sleeping bags.
Lower Limit The temperature at which a standard man can sleep for eight hours in a curled position without waking. If you consider yourself a warm sleeper, use this rating to decide the coldest temperature the sleeping bag is suitable for. We emphasise the Lower Limit temperature for all our unisex sleeping bags.
Extreme This is a survival only rating for a standard woman. Between the lower limit and the extreme rating a strong sensation of cold must be expected and there is a risk of health damage due to hypothermia. This is an extreme survival rating only; we do not recommend you rely on this rating for normal use.

[Maineiac64]

The forums here are full of great info. Everyone sleeps different and your comfort depends on your sleep system including sleeping pad as well as a myriad of other factors. I personally sleep cold and use a good 20 degree bag with an insulated pad below about 40 and then will use a quilt above that. It will also depend on where you plan to be for 3 season. Good luck.

[coach lou]

I have 3 WM bags and another manufacturers 15* rated bag. The -20 Puma, I have never been able to zip up, and prolly will never get the opportunity to do it. I got the Everlite to use in the Huts, but with long johns it is Memorial day to Halloween. This year I bought the Alpinlite....20*, because the "other" bag is not a 15* and I don't even like the feel inside. The Alpinlite is lighter and way warmer. The WM web page will tell you that you can use the Everlite as an overbag to make your winter bag warmer. So this years lack of winter allowed me to give that a try. Nice and toasty warm in the high 20's, didn't really need it, but I like it and it is 2.8 lbs.(both) compared to 3.2 lbs for the Puma.

I think the WM ratings are pretty accurate...........the "others" not so much.

I will add to what someone else eluded to.....A good night sleep is a most important part of long distance hiking. Don't skimp on that, you will pay later. GET THE WARM LIGHT BAG.

My Puma is 16 years old....used at least 10 nights a year.

If anymore wants that "other" bag, rated to 15* I'll part with it and the Pacific Outdoor Equipment pad it came with.

[Time Zone]

Those ratings must be taken in context - there are a lot of assumptions behind them, such as how much insulation you have in the sleeping pad beneath you, what you are wearing as PJs, and the definition of a standard man/woman (height, weight, age).

If I, as an over-50, over 6 feet tall man, over 175 lbs, had a 30F bag on a 30F night, and an R2.8 pad under me and some thin thermal u/w for PJs, I'd be very cold indeed, as I would be "out of range" on ALL the underlying assumptions of that bag rating.

[blackmagic]

Temperature ratings for sleeping bags are not standardized.

Some vendors rate their bags for comfort; others rate them for survival.

The uninformed consumer expectation is for comfort; thus, a bag (or quilt) from REI will be comfortable at its temperature rating for most, lest they risk the wrath of angry customers.

With cottage vendors, ymmv.

Regardless of insulation type, there is an approximately linear relationship (for normal temperatures) between loft height and temperature rating. The fine folks at Backpacking Light did the regression and came up with a "rule of thumb" formula:

minimum temperature °F = 100 – 40 * loft in inches

Per that formula, 1.5" = 40°F, 2" = 20°F, 2.5" = 0°F.

FWIW, Andrew Skurka does not use quilts below about 20°F, (https://andrewskurka.com/review-western-mountaineering-astralite/) and I agree with his assessment:


I see little sense in a quilt that is rated for temperatures colder than the high-20’s. Beyond this threshold, high-loft head insulation is absolutely mandatory, and at that point you might as well use a traditionally mummy bag, which is simpler and less vulnerable to drafts.

...At least for tents. The ergonomics of quilts are different for hammocks, and they are usable, if not preferable (with accommodations for head insulation), in deep winter conditions.

[Time Zone]

Temperature ratings for sleeping bags are not standardized.



I believe EN Ratings are standardized, and the terminology upthread (comfort, lower limit, extreme, and "standard woman") are all terms defined in EN 13537 ratings. Therefore my reply was predicated on the assumption that we're talking about EN ratings of sleeping bags.

https://en.wikipedia.org/wiki/EN_13537

[4eyedbuzzard]

Here's the thing with those comfort vs lower limit ratings though. Your a guy (we're tough) and figure okay I can tough out a night or two at the lower limit (which already factors in wearing base layers, socks and hat). Except you limp into camp cold, maybe a little wet, and tired. Your body is not in a good condition to produce a lot of heat. Even after eating and some warm fluids you're likely going to be cold in a bag at the lower limit. Add then any wind / drafts and that your bag has lost some loft and insulative capacity due to trail use, moisture, and dirt and you are in for a cold night. Best to stick with the comfort rating from a reputable manufacturer.

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[Slo-go'en]

I've tested the "extreme" limits of my sleep system more then a few times. It sure gets you up and moving at first light :)
28 degrees and a stiff wind blowing into the shelter is lots of fun with a 40* low limit sleep system.

I tend to pack a little light in the late spring, knowing much warmer temps are not far in the future. I'll admit I have loft envy at times when I see other bags all nice and fluffed up.

[OwenM]

28's perfectly comfortable for me in my 42.6F low limit bag, but I sleep much, much warmer than a normal human.
And therein lies the problem with even an objective EN rating system.
There's an uncontrollable variable, and it is US!
People seem to look at that rating and ignore the specified layers and pad r value, AND the additional fact that both the testing for r-values and EN ratings are arrived at using heated plates and heated mannequins, respectively.
If you don't put out as much heat as those standardized heat sources, your pad's r value drops, and your insulation doesn't have as much heat to keep in, so can't match its rating.
If you put out more, that r value goes up, and those EN limits go down.
That doesn't mean there's anything wrong with you, or wrong with your gear. Some of us just sleep warmer or colder, and need more or less insulation.
But you have to find out firsthand, through personal experience. You might get some useful suggestions, but some other person on the internet can't answer these questions for you.

I've got a good friend I've backpacked with a few times, now, including some short winter stuff. He sleeps about 10F cooler than average, while I run 15-20F hotter than average. That is a HUGE difference. Rest assured, neither of us is giving the other advice about which pad or bag to bring!

Sleeping hot is kinda awesome, though. Let's you carry less weight and bulk. And maybe pick at someone now and then:D

[Hikingjim]

If you're comparing to quilt ratings, I would say your current bag would be most comparable in warmth to popular 20f rated quilts. Except you would need to add more head/neck insulation with the quilt, since the bag has a hood

[Another Kevin]

People vary.

I don't _think_ I'm either a particularly cold or warm sleeper.

The 'extreme' limit is a survival limit. I won't have any fun at the 'extreme' limit. Or get any sleep.

I'm perfectly fine with pushing my sleeping bag to the 'lower' rather than the 'comfort' limit if I use two pads, and sleep in baselayer, wool socks, glove liners and balaclava.

If it gets five or ten F colder, I can put on my fleece jacket and pants, layer another pair of socks, put on mittens and tuque, and throw my puffy on top of the bag over my core. That's enough for me to get some sleep at about minus single digits F (-22 C or so) in a down Marmot bag that's got a 'lower' EN rating of -18C/0F. If I know I'll be pushing the system hard, I'll bring a six-foot length of Reflectix or a car sunshade to put inside the sleeping bag under me. But mostly I don't plan to push the limits, it's more "in case it's colder than forecast."

At 'comfort' temperature, I'm most likely sleeping in my briefs. Maybe I'll leave my balaclava on, because while the human neck is no doubt necessary, it's hard to keep warm.

If it gets very much above 'comfort' temperature, I might be unzipping the bag and throwing it over me like a quilt.

Hmm, does this scale to summer weight? Yeah, I think so. With a summer-weight bag, I'll want to wear fleeces or a baselayer if there's a sudden cold snap into the 30s, I'm fine in briefs at 55, and at 75 I've got the bag unzipped and have it just over part of me.

Deep subzero conditions (if you're looking at a -20F or -40F bag) are a special topic that I'm not getting into in this post.

All of this is presuming EN13537 ratings, not just some lie from the manufacturer.

My daughter runs about the same as me, but my wife runs at least 15F colder, and so needs more insulation. A lot of mornings at home, I wake up on top of the duvet that she's sleeping under, or find that I'm sleeping in boxers when she's wearing sweats, so yes, people vary. It's a good thing that my wife isn't a hiker, because she'd have to carry kind of heavy to stay warm.

Skurka is right that below 20F/-7C, ground dwellers need a sleeping bag rather than a quilt. That's also getting into the range where you need two sleeping pads, and at least one must be foam. (You don't want to have an inflatable as your only pad, lest a pinhole turn into a survival situation. The foam goes on TOP of the inflatable.)