Am I missing something?

[Daniel Cox]

I don't want this thread to descend into another synthetic vs down, but I have been debating the purchase of a montbell thermawrap parka and pants set up vs an alpine light parka and down inner pants. My concern here is when people refer to having each in the rain how the down will collapse and the synthetic wont. Is this not the reason you carry a shell, so that your clothes don't get soaked and you don't become hypothermic? Am I missing something here as to why this seemingly very obvious solution would not work? Obviously there will be some collapse from the moisture in the air, but otherwise I would imagine any reasonable shell would protect the down just fine.

[Ashley Brown]

Don't think you're missing anything. Down + shell is fine unless you're in continual rain and damp for days on end.

Some people like synthetic because it means they don't have to worry about keeping it completely dry, plus the extra piece of mind I guess. And you can wear a pack without crushing the insulation to bits.

Unless you are always in extended wet conditions I would go for down.

[Misfit Mystic]

Hi Daniel, another thing to consider is the difference in warmth between the Thermawrap and the Alpine Light. According to Richard Nisley, a member of these forums, the Alpine Light is about 3 times warmer than the Thermawrap. If I remember Richard's chart correctly, the Alpine Light had a CLO of 2.51, while the Thermawrap was .77(?). These results were obtained from a testing protocol Richard has established; there is an extensive thread about it.

[Richard Nisley]

Daniel,

Your assessment is correct in that any reasonably sized shell will protect the down just fine. There are two additional benefits beyond down’s more obvious benefits of 1) warmth, 2) weight, and 3) durability versus the Thermawrap's.

4) Down, worn as a mid layer, benefits from your much higher metabolic rate when doing camp chores versus sleeping. Also there is much more of a bellows effect when doing camp chores. Combined, these factors tend to continually dry out down insulation garments versus sleeping bags which will continue to accumulate insensible moisture unless hung to dry.

5) The outer shell has the added benefit of significantly improving the warmth of sewn through down garments. The shell provides an incremental ~12mm of insulating dead air space on top of the down garment’s concave sewn-through seam channels. The outer shell significantly increases the warmth of the sewn through down garment more than it would with a uniform thickness garment.

There are environments where the Thermawrap would be a better choice for an insulation layer. Some that come to mind are the rain forests of SE Alaska, water sports activities such as packrafting, etc.

The down insulating garment is not a viable substitute for a base layer and a relatively light insulating layer for actually backpacking. Down under pressure from the pack harness will totally collapse. Also perspiration, from over heating, can collapse the down.

[Anonymous]

Richard, could you write a treatise on you findings and post it up to the wiki or something else. I think if you were to group all the pieces of information you have been putting out it would be helpful to quite a few people.

[Luke Moffat]

I wish I had read this prior to pulling the trigger on the thermawrap pants and parka I purchased last night. However, based on what you wrote I think I made the right descion anyways. I am getting in to packrafting here in Alaska and also have 10 day backpacking trip planned for Kodiak in October.

I was torn between down and synethic and the warm ratio down brings to the table is VERY appealing, but being as I will be in a damp environment a lot of the time I think I made the right descion. Thanks again for your explanation on the difference and benefits between the two.

[Adrian B]

I wouldn't wear either synthetic insulation or down in the rain, even with a waterproof rain shell and rain pants. Spend a couple of hours walking in heavy rain and you'll find that _no_ shell will keep you dry.

Often when talking about collapsing insulation, the moisture concerned is condensation from insensible perspiration or wearing damp clothes (eg baselayer) beneath.

[Mike W]

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[Luke Moffat]

Yes I agree. I wouldn't wear this insulation garmet for hiking unless its 15 degrees or colder (no rain). These are more for when sitting still and in and aroudn camp when you are no longer producing as much body heat due to the lack of motion as you are no longer hiking. A fleece vest and a good base layer and I am warm down to 15 degrees or so while hiking. Its when the hiking stops is when the insulating layers are needed.

[Daniel Cox]

Thanks everyone for the great replies! Everyones input helped a lot, and I've decided to go with the full down set up.

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