Upon starting to read up on sleeping bags, I have not found one single article that explains all the many questions I have had.
You see such things as 190T 300GSM and Season Rating.
All very well if you understand all these terms, but, if like me, you are in the dark about some of these terms, I will try to explain.
Firstly the 190T. The T is the number of threads per square inch. These are the total number of threads at right angles to each other, as in a cross hatch pattern. Web and Weave. The higher this number is, the more densely packed the material.
Sometimes you will see 2 sets of figures for the inner and the outer. The outer stops moisture penetration, the lower number is usually the interior, which need to be breathable.
This is not just limited to sleeping bags, but also tents and awnings, or indeed any material. The T number can be directly linked to the static head of untreated material.
Secondly the GSM rating.
This is the weight of the material used in the filling in grams per square metre. It can be related to how warm the sleeping bag is, but it all depends on the filling used and the baffle arrangement. Duck Down is pretty light compared to synthetic materials so its GSM rating is lower than many synthetic bags. So GSM can only be used as a rough estimate. If the bag is double baffled in 2 layers the temperature rating will be far better for the equivalent GSM to that of a single layer.
Season Rating, I have found, is variable and is a rough guide, with manufacturers making claims as to the number of seasons. 4 Seasons in the equatorial region, is not the same as 4 seasons in the northern/southern latitudes, so season ratings are only of use as another rough guide.
Temperature ratings are the only sure fire way of rating how good a sleeping bag is, and even that is fraught with difficulty for the uninitiated.
As far as other factors with regards to how efficient a sleeping bag is, and what type to get, there are many opinions based on personal preferences.
Double Sleeping bags can be warmer, due to the fact 2 people share body heat, but some complain that when one person moves away the air gap between the 2 bodies makes a cold spot. This is basically because the choice of sleeping bag is wrong in the first place, not temperature rated properly.
Another point is that mainly females do require a warmer bag than men, not a problem as a zip down either side can alleviate too much heat for the male.
Construction of the sleeping bag is also important, mummy bags including double mummy bags are usually more efficient. Baffles on the insides covering the zips and the outside stop unwanted cold spots.
Choosing a good sleeping bag is important so take your time and look at a few of them. Shops can have good advice, but many just want to sell you a bag that is sort of OK. Buyer Beware of sales people.
Choose the lowest temperature rating for the season you are going to use the bag in. A decent bag will have a double zip that allows air flow through the bag. A double zip that can move up from the foot and slide down from the top. Usually found ob single bags and a must have for temperature control.
Hope this helps at least some, but please tell us what bag you use at present ? How many erm season its supposed to be ? and what temperature rating it is ?, if you have that.
Great stuff.
It used to be much simpler. A 5 season bag in the eighties would keep you warm down to -20. Now it all seems a triumph of hype over practicality.
We currently use the following:
Snugpak the sleeping bag for backpacking. Sold as a 4 season. More like a three. Needs a fleece liner.
Soldier 95 ex army bag. A true cold weather bag but huge pack size and a footbox so no way to vent hot tootsies. Truly bombproof.
A Dutch army cold weather bag with pop on goretex Bivvy bag. Similar to the soldier 95. Maybe a bit thinner but the Bivvy bag adds a layer. It has a full length zip for venting at the foot. Both bags are centre zip which I prefer. The Bivvy bag has sleeves for a mat and poppers to attach to the sleeping bag. I have yet to try this out in the winter but coupled with the Bivvy bag and a fleece liner I reckon it has a comfort level of about -20.
The wife uses a cyprinus carp fishing bag for cold weather use. Very warm but bulky. Has a soft inner, a luxury bag.
I'm a strong believer in sleeping with the bare minimum of clothing, letting my body heat warm the bag. Others say this is wrong. Baffles and a hood is therefore important. I think a lot of the carp fishing bags give an erroneous temperature rating as they are designed to be worn whilst fully clothed.
Stitching is important. No through stitching. No cold bridges. Offset channels are probably best. As for down v synthetic. I have always gone for synthetic because it is usually damp. Now I'm mainly car camping, size isn't so much an issue so down isn't needed.
We all use Outwell Campion Luxes at the moment. Synthetic fill, square end. Can zip two together if wanted. As far as I remember we bought them from Bergzeit and they showed a temperature rating for men and women. Any rating system needs assessing for your personal needs though. My OH & son feel the cold far more than I do.
I forgot about the Coleman Hudson double. Lovely feeling bag but rubbish at keeping you warm. The wife moves and all the warm air goes out the top. We don't use it any more.
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