Winter sleeping bag

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New member
Sep 3, 2003
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Hudson, Quebec, Canada
I am going to purchase a winter bag in the -25C to -30C range and was certain I would need to be duying down. However research is showing me that Polarguard Delta is now as light as down and a similar size. Comparing a North Face Tundra (Polarguard) and Solarflare (down) the specs on size temp and weight are virtually identical. Since synthetic is more wet tolerant and a lot cheaper - is down now a thing of the past?
I don't know the fill specifics of PGD Delta, it might be as light and/or as compressible, but I would be hardpressed to say that there is a synth anywhere that has the life of down which is a major benefit of down.

Synths will lose loft over time and when that loft drops, the temp rating climbs -25C might be -5C in 3-4 years. Might be 0c in 4-5 years, but it also depends how you store it, wash it and care for it.

If you are looking for a quality bag and do not want to be saying in 5 years:
"I wish I spent the money on down", then buy down now. If you are just looking for bag and are not too concerned about fill rating longevity or if you do not think you will retain a flagging interest in winter camping in the years to come, then it might be better to go the the route of a synth bag. Good luck!!! :)
Down VS Synth?

This could easily degenerate into another down vs synth debate ;) - it is usually pretty sad watching normally nice folks really dig in their heels and "tee off" on one another.

To address you question, there are pluses and minuses with each choice. For me and imho, synth bags loose loft too soon meaning more frequent re-purchasing, (were?) are too heavy/bulky, and the whole "warm when wet" thing is pretty moot for cold-temp (winter) bags as i personally have rarely encountered enough liquid water to cause concern.

To each his/her own.....

Jacko said:
Since synthetic is more wet tolerant and a lot cheaper - is down now a thing of the past?
No, but this is a good "pick up" as these are the first 2 bags I've ever seen that are actually rated, weigh and stuff the same. The only apparent difference is the fill and price. So if the ratings can be trusted, it comes down to the differences; Down lasts almost forever but does poorly when damp, synth does not last as long and does much better when wet. If you can stay dry you would buy 3 synth bags in the next 10 to 15 years and still have the original down.
At those temps there shouldn't be any moisture to worry about.

That being said, Mountain Gear is having a sale on the Mountain Hardwear 5th Dimension sleeping bag for $250. I thought about picking one up, and still may as I nest sleeping bags together for anything in the negative range. But, this has worked for me down to -40°, it's just heavier than I'd like.
Lawn Sale said:
At those temps there shouldn't be any moisture to worry about.
External moisture is not the problem--moisture from your skin will condense and freeze in the bag. Not an issue for single nights, but over a period of several days or more, a down bag will lose loft. On a multi-day trip, one should air and dry one's bag whenever possible. A VBL will also help keep this moisture out of your bag.

I too am skeptical

that a synthetic could equal down on the basis of equal weight, size and temp wise. Who rates the bags, are they independently rated, or manufacturer rated?
I have never found a bag worthy of the temp ratings, so I must be a cold sleeper.
That being said, everyone has their own preferences, I own both types...
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I started off buying only synthetic bags because I was afraid of wet down bags. Also, I solo-ed a lot and didn't want to be caught in the woods alone with a bag that wouldn't insulate. After buying 4 synthetic bags, 3 of which I LOVED, I gained enough experience to feel comfortable knowing that with proper attention and care during my trips, a wet bag wasn't the norm and so I ventured into the down bag arena . . . and now I won't buy synthetic again. Once you go down you never go back ;)

I find down more comfortable and warmer at the same "rating". I have never slept in a synthetic bag at the temp it is rated for and been comfortable however, I have pushed the limits of my down bags to 3 degrees below its rating and been very comfortable.

Also, there is something psychologically warmer about down, it is just so puffy and cozy looking :D

If I was suggesting a bag for a beginner, I might still tell them to go synthetic until they figure out if they love the sport enough to commit more money but for personal bags, I will always buy down.

The above opinions are not based on a love/hate down/synthetic or on numbers and stats but on a completely personal and unhindered by data opinion by one user . . . me !! :D :D

I recommend Western Mountaineering bags, expensive but oh so comfy.

BTW, the original poster did phrase the question in a manner that would bring up the down vs. synthetic question so I don't think the re-hashing of that topic, however redundant would be off-topic for this thread ???

North Face Tundra and Solarflare specs are here
Now I dont see why they would oversell the synthic tundra over their own much more expensive down equivilent.
It appears to me that if longevity is the only reason to shell out the additional 450$. Thats a lot of cash to lay out for a bag that will only be used during one season. I would just have to look after it well in storage.
I have just read Chips reviews - and confess that they are terrible. Now I'll just have to sell the kids to buy a down bag. Oh well never mind I'll just do more research and not buy!
Bag ratings

Bob, here is how they rate bags sold in Europe-

It is my understanding from discussing bag ratings with the folks at MacPac, the NZ company, that all bags sold in the EU have to be tested and rated, so at least they can be compared among the EU rated bags.

No idea how Americans rate their bags.
Back in the '70s, EMS did their own loft measurments and ratings, which were at least consistent across manufacturers. Results were published in their catalogs. (1974 was a particularly good one...) Also included the insulation tables that I have posted in previous threads.

You might take a look at the EMS Mountain-Light (or is it Mountain-Lite) series (down). Includes -40F and -20F models. They appear to be decent bags at a reasonable price.

As posted above weastern mountineering bags are very nice, I have had a few chances now to push them well below rating, 40f bag down into the 30s and high 20s and a 15f bag down to 5F, cool, but not cold at 3am.

Look at the loft numbers, WM loft will be higher at a given rating than most other bags. I froze in a 0f synthetic bag be it a few years old at about 10f last spring, and that convinced me.

Can't wait to try out a highlite inside an ultralite this winter, for me I would think it should work to -15f ?
My synthetic bag were never as good as their rating and would lose loft after a few uses. I bought down and love it. I would absolutely go with down.