I am looking at building a 3-Layer Sleeping system and want it good down to 20F: parka/pants + mummy bag + bivy. Planning on sleeping under a tarp.

Wondering what people would recommend as far synthetic bag and bivy. I am a side sleeper and not interested in quilts.

Ground Pad: GG NightLight Sleeping Pad + ThinLight 1/4"
Parka: MontBell Thermawrap Parka
Pants: BPL UL 60
Bag: ? how much does a Thermawrap extend a bag
Bivy: ? no idea on this one

For 20F conditions backpacking I currently use a WM Ultralite and the pad setup and find it true to its warmth rating.

Options for a 3 layer system >

1. Go to Brigade Quartermaster & search for it. Two systems were available in Dec.

2. Google Snugpak (a British company) they have the best system I've seeen for synthetic bags.

Edited by Danepacker on 01/02/2010 11:02:54 MST.

Steve,

I love my Thermawrap! It excels as a parka (as part of a clothing SYSTEM or if not extremely cold) and as a sleep system extender.

I generally use it w/my JRB No Sniveller (down quilt). I have been comfortable down to 19* w/it and poly base layers, smartwool socks, and of course a hat (in that case a JRB down hood). Not your exact system, but hopefully it gives some perspective. Without the Thermawrap I wouldn't have made it comfortably at those temps - but I haven't tested this system to its limit without the Thermawrap, so giving you an estimate of how much it extends a sleep system is tough - I would estimate 10deg F.

Note that I didn't needinsulated pants. YMMV.

Let us know what you choose, and how it works out.