Sleeping Bag Ratings - Fact or Fiction?

[misanthropist]

I suspect they are including both a ground pad and a tent in their calculations.

If you are going without either I think you'd have to shave 15 degrees or more off their claims.

My MEC bag is rated at -12 C and with a pad but with no tent, which is how I use it, I think most people would be uncomfortable at -5.

 

[Thomas Linton]

I suspect they are including both a ground pad and a tent in their calculations.

If you are going without either I think you'd have to shave 15 degrees or more off their claims.

My MEC bag is rated at -12 C and with a pad but with no tent, which is how I use it, I think most people would be uncomfortable at -5.

I have read several etimates that the tent is worth 10 F. Sleeping on cold ground with your weight pressing the air (insulation) out at the hips and shoulders, and back of the calves would not be pleasant.

I spent a 25F night in a USA Arctic bag (light canvas over cover) on a closed-cell foam pad no tent and lots of wind. Worst night I ever had - teeth chattering and all that.

 

[Seahawk]

I believe that most companies assume that you will be using a sleeping pad and a tent. When it comes to determining how well a sleeping bag holds heat given the type of insulation, the amount of insulation, design, cut etc. there is no standard.

Here is a link to an article on sleeping bag ratings: http://www.adventuresportsonline.com/sleepingtemp.htm

If you don't want to read the whole thing, here are a couple of excerpts:

"Testing instruments such as the copper mannequin provide clo data using a very controlled environment. The mannequin is a fixed size and does not roll. The comparative data that's collected is great for evaluating the comparative insulating power of bags used by the mannequin," adds Williams, "but how does it address the variables of body size (a small body in a large bag) or movement (nighttime rollers who constantly crush insulation), metabolism, and the other factors of the field?" (Fred Williams, founder and past president of Moonstone)

One company, when asked how they were rating their bags, went so far as to state that they had their bags tested by the copper mannequin a number of years ago, and simply extrapolated the information into their current line. (Michael Hodgson, the article's author)

 

[Bushman5]

I found that a good way to keep warm at night is to eat HIGH FAT foods prior to sleeping. foods such as chocolate, pasta with meat, cheeses and etc etc etc

 

[Thomas Linton]

I found that a good way to keep warm at night is to eat HIGH FAT foods prior to sleeping. foods such as chocolate, pasta with meat, cheeses and etc etc etc

Another example of how ratings do not rate YOU. I follow your advice, Bushman. :thumbup:

I have a friend who, for whatever reason(s), thinks eating before going to sleep makes him colder.

________________________
Give me that Wisconsin cheese, moo moo, moo moo.

 

[misanthropist]

Eating before bed works for me...although the trouble I have is that if I move around much before going to bed, it can take hours for me to fall asleep.

I have severe insomnia a lot of the time and if I get up and exercise before bed, forget it. I may have hiked thirty or forty kilometers with a full pack that day, and slept four hours the night before, and the night before that...but now I'm going to be awake until 3 am.

Quite annoying! I always need to bring books when I camp so that I will have something to do between ten pm, when I usually head off to bed, and two am, when I usually fall asleep.

There is always the option of staying up until two...but then I won't sleep until four (a two hour improvement in a sense...but not very useful at the same time!)

Unfortunately I am not one of those people who only needs a few hours sleep each night, either! I am pretty functional on two hours of sleep for weeks at a time but I really don't feel happy unless I am getting close to eight.

Still, it's much better out in the wilderness than in the city, where I sometimes miss a complete night of sleep once every two weeks. I am always caught up on my reading but doing ten hours of physical labour on Friday after twelve hours of sleep total during the week is more than a little draining!

Anyway hijack over...I would guess a tent is good for 10f in nominal wind but as you say, high winds is something else altogether!

My old Canadian arctic setup was barely tolerable in -15 when used without a tent. I had most of my clothes on, a toque and a nice prolite 4 mat, and man, you wouldn't have wanted a single feather blowing out of that system!

Of course it was fairly windy, come to think of it.