Originally Posted By: Am_Fear_Liath_Mor

A sleeping bag suitable for -18C use will be bulky. You can get half the bulk of a synthetic bag if you select high specification down with 700 Fill power - 800 (very rare) and 900 fill power doesn't really exist. The down bag will weigh a minimum of 1.6 to 1.7 Kg mostly dependent on the size as some of the lighter bags will have a very tight fit i.e. for mountaineers who tend to be quite lean even compared to today's military personnel). Cost of the down bag will be between $400-600.

A synthetic bag will be quite bulky and will typically weigh between 2.8 to 3Kg. Synthetic bags, which will go down to such low temperatures are actually few and far between. There are some bags from Snugpak. Cost will be approx half that of a top end down bag.

This is essentially the sleep system I will use for cold weather. (comparison in size and weight to the US Modular Sleep System)

http://www.youtube.com/watch?v=fES2kb29smw



SgtFruitcake has tried to compare apples to oranges. He is comparing a what appears to be an excellent but,(as you point out) small single down bag rated for -5 or so with a full size double bag rated to -30. His silk liner and WATERPROOF overbag will not bring it down that much (5 or so at the most). He also appears to be recommending an overbag that will make his excellent down bag (or any other) a frozen lump in only a few days. Coated nylon vapor barriers are used by some (not me) as liners, but the half liter or so of sweat every night will soak the bag then in the day it will freeze up. NOT for me, thanks.

He also does not seem to know that the military bag shown is available on the internet at reasonable prices or from the original manufacturer (Wiggy's) new at any time. They also (as well as others) have synthetic bags rated (and good to) the lowest temps of any bag around. Selection is there. No relationship to Wiggy's except as a satisfied customer.

I agree with those who recommend a synthetic bag for scouts. I would dearly love to have my old Holubar down bag back (Alice Holubar was an artist with the sewing machine), but there are places where down is surpassed by synthetic and youngsters (like the scouts I work with) are one place. I think you will find that with careful selection you can find a synthetic that is only a little heavier and more bulky (15 - 20%, not twice) just don't try to compare ultralight gear with military surplus.

Respectfully,

Jerry