Insulation layer: loose or tight?

(…continued – forum seems to hang posting 'long' message?!)

But does a close fitting insulation layer perform better? Conventional wisdom with sleeping bags seems to be that air space is bad, which would seem to apply to jackets too. In which case to get the larger, more flexible, guaranteed-no-compression fit there might be a slight performance hit. (On the other hand, when it really matters you'd be using that flexibility by wearing something underneath.)

Hi Adrian-

Specific to the Cocoons, I noticed the same thing. My 2007 large hoody is cut much more roomy than my older (2005?) pullover. I need the arm length, otherwise I would downsize to a medium. (I'm 6'2", 160 lb.)

In general, maximum warmth will be achieved if the garment fits snugly enough to eliminate air pockets, but not so snugly that the insulation is compressed. Your sleeping bag analogy is spot on — in fact a proper fit is even more critical in a garment because you move around more when wearing it, increasing "bellows effect" convective heat loss over a sleeping bag where you are more or less stationary.

Cheers,

-Mike

Well I’ve taken the plunge and ordered the small. I’m a bit confused by the difference between the original sizing chart linked to with the prepurchase (http://www.bozemanmountainworks.com/?do=showpage&id=18) and the sizings which have been added to the cocoon pages recently (http://www.backpackinglight.com/cgi-bin/backpackinglight/cocoon_ul_60_hoody.html): seems the latter reflect the larger sizings of the garments?

If anyone in New Zealand is interested in saving postage on a medium Cocoon hoody, if you’re quick you can get a good deal before I send it back (http://www.trademe.co.nz/Browse/Listing.aspx?id=108324616&ed=true).