Using a space blanket

[canoeski]

I'm not disputing this, but when you lay in your hammock and that puffy down underquilt starts doin' it's thing, it sure FEELS like it's reflecting your heat. It even feels like it's generating a little extra. What an incredible feeling!




Jerry

I hear ya Jerry! It sure does feel that way. I think down is just a superb insulator and a boundary layer immediately comes up to body temp when in close contact.

Now, you never know, nature is so clever that perhaps there is a minor reflective property of down; but I'd think it's fairly minor.

All of my sleeping bags are down (Marmot with Goretex shells), and the thin inner shell accentuates that warm and cozy feeling. My new JRB quilts are the same (my wife and son both draped themselves with them and you should have heard the "Ooo's and Ahhhhs")

Even with the Mylar you eventually reach a cozy thermodynamic equilibrium.

[Knotty]

Seriously doubt down has any heat reflective qualities. It's just a very good insulator so you quickly feel warm. Kind of informs you of how much heat you are normally losing.

Down works by preventing convection and conduction.