Sleeping Bags & Temperature Ratings?

[cdwscout]

[Admin note: Split from Hammock.]

Revisiting the thread after spending a night with it in 30 degree weather, I was freezing, even in my 30 degree sleeping bag. I plan on eventually getting a Hennessy explorer with an insulation system to solve my cold toes.

[RWSmith]

Surprisingly, I can't remember us ever having this conversation on this board.

I mean, maybe it's just me, but after years of experience... I've learned to never go out w/o my bag being rated at least 20 degrees below the expected max. low.

IOW, the manufacturers are either liars, or nuts... or, I'm just that "different".

I sure would like to know how others rate their bags?

[topshot]

There's no rating system in the US so most bags have been rated arbitrarily or the rating means different things for different brands (comfort level vs survive level). The higher-end brands are often more accurate but not always. If you can find one rated by the EN 13537 standard it should be accurate. You can get a ROUGH comparison between bags by comparing their loft.

What's just as important but often neglected is insulation underneath you since the bag provides hardly any in that area. You need a decent pad or pads.

[miksmi]

Here are articles from two trusted sources (and a manufacturer) about "EN 13537:2002 Requirements for Sleeping Bags", the official European criterion for the classification of sleeping bags. There is no such standard in the US.

Sleeping System, Mark Verber.
Deciphering EN13537 Sleeping Bag Temperature Ratings, SectionHiker, Philip Werner.
Sleep Well, Mammut. A manufacturer's perspective, including practical advice for consumers and the cost of testing.

Mark's and Philip's sites have a wealth of information and includes experience and opinions on gear.

Bags rated at EN 13537 "Comfort limit" don't mean you're going to sleep comfortably without being cold; they're just a way to standardize the temperature ratings and there are differing opinions:

Issues Concerning the EN 13537 Sleeping Bag Standard, Outdoor Industry Association.
Sleeping Bag Temperature Ratings: Fact or Fantasy?, SectionHiker, Philip Werner.

In another trusted source, The Backpacker's Handbook, 4ed, Chris Townsend states:

Having looked at some EN 13537-rated bags, I would expect to feel cold in them long before the extreme temperature was reached, and I'm a warm sleeper. Overall, I think this rating is meaningless and should be ignored.

I highly recommend this comprehensive book for details on fabrics and material used in manufacture of backpacking gear, understanding why shoe sizes differ between manufacturers and how to compensate, lightening your load, as well as Chris's recommendations. Chris is a Gear Editor for TGO Magazine and was a Senior Gear Editor for Backpacking Light; he still posts in the forums there.

Me? I'm a cold sleeper and like RW, choose bags rated 20F degrees below the expected maximum low.

[topshot]

In another trusted source, The Backpacker's Handbook, 4ed, Chris Townsend states:

Having looked at some EN 13537-rated bags, I would expect to feel cold in them long before the extreme temperature was reached, and I'm a warm sleeper. Overall, I think this rating is meaningless and should be ignored.

While I liked his latest edition, it did have several faults and this is one of them. I would EXPECT ANYBODY to be cold at the extreme rating. He either doesn't understand the rating or didn't bother to look. The extreme rating is the minimum temperature at which a standard woman can remain for six hours without risk of death from hypothermia. He should have been looking at the comfort rating, the temperature at which a standard woman can expect to sleep comfortably in a relaxed position, which is SIGNIFICANTLY higher.

[miksmi]

Perhaps I should have quoted more context. He makes the same point you are; see page 241. Apologies for misleading you.

[topshot]

Perhaps I should have quoted more context. He makes the same point you are; see page 241. Apologies for misleading you.

I should have looked it up again before replying but couldn't find my book, which also has my list of nitpicks for my eventual review. I see he was saying the extreme classification was meaningless, not the actual standard. I can agree with that. Just the snippet you originally posted made it appear he said the standard was meaningless, which was incorrect.