Originally Posted by
3speed
For weight, synthetic is there now. They're making really nice, light weight hollow tube synthetic insulations. They don't compress as much as down, but they compress small enough. They certainly at least "come close" to down.
I have never seen a synthetic bag that comes close to the likes of the Mountain Hardwear Phantom line, or the Marmot Atom, Hydrogen, or Helium.
My daughter is very allergic to down and when sleeping in the same tent as her I use a synthetic bag. I bought a North Face Cat's Meow and it the best performer that I could find in a synthetic at the time, but it is still a good bit heavier than the Marmot Helium and the Mountain Hardwear Phantom 15 both of which are EN rated about 5 F lower. Is there actually something substantially lighter that a Cats Meow in a mummy bag EN rated at 20 F or less?