Is there a rectangular sleeping bag that can compress as small as a mummy bag?
Submitted by – Andrew – Waterloo, IA
Not really. There’s no magic to it. When you have, for instance, a 20°F bag that is rectangular and a 20°F bag that is a mummy, there’s a lot less fabric, insulation, and material in that tapered mummy bag. So it will undoubtedly be smaller and lighter.
If you want mummy-bag packability with rectangular-bag roominess, however, I do have a couple of suggestions for you:
—Check out MontBell’s Ultralight Spiral Down Hugger, which we loved so much we gave it our Editors’ Choice Award back in ’09. It, along with several other MontBell bags, has diagonal stretchy baffles, which hug your body like a mummy, but allows for expansion in several directions, so you can toss and turn much more freely.
—Another option is a quilt system, like the Therm-a-Rest Alpine Down Blanket. It drapes over your body and attaches directly to your pad, so it feels more like the quilt on your bed. And because there’s no bottom-side insulation, it packs down to volleyball size (good down to 35°F)
—Big Agnes also makes a whole slew of SEMI-rectangular bags (they have a slight taper to shave weight but still offer more volume that a mummy). These bags also have no bottom-side insulation; instead they have a sleeve into which you slip and insulated mattress to provide you with backside warmth.