Cozy, eazy, cheap, super lightweight

[theoilman]

Super easy to make cozy for boiling bag cooking: Take a piece of bubble wrap, wrap it loosely around whatever boiling bag you are using (homemade dehydrated or prebought meals), cut length a little long, tape the seam, tape or staple row the bottom. I use clear packing tape, but most any will work. Will probably wear out in a couple of weeks of regular use, just make extras and mail drop them.

[Rocket Jones]

I do something similar, but added a layer of heavy foil on the inside and outside. It lasted a year before needing to be replaced.

[Cruiser]

I use a stocking cap its dual purpose.

[tridavis]

Tobaggon does the same thing, just be careful not to spill in it.

[MuddyWaters]

buy a bubble mailing envelope thats plastic, not paper. Trim to fit freezer bag better. 0.65 oz. To improve it, cut a litlle piece of mylar space blanket and tape into shape for liner with scotch tape, adds .05 oz. Can fill in with polyester fiberfill from old stuffed animal too to make more insulating (but heavier) for winter.