Bushwalk Australia

Today I bought a metallised closed cell foam mat for $4 from Vinnies. It seems quite firm & dense (black) foam (no brand name). I am thinking of keeping it in reserve for use under my NeoAir XLite in the deeper cold. I bought the XLite during the GFC when these things were very affordable on MassDrop. Now I am older & some 20 kg lighter, I sleep colder these days & this option is 1% of the cost of upgrading to an XTherm, plus I don't do many winter nights as the dark is sooo looong & boring & well cold. However, I am not sure whether the metallised side goes up or down. It doesn't seem cold to the touch unlike Mylar. Any ideas, Does it matter?

From a physics perspective it doesn't matter. The internal and external sides of the metallised layer can reflect heat back towards you.

Anyhow, most of the benefit will come from the closed cells rather than from the shiny surface.

Ta, that's what I thought but I wasn't sure as IR, convection & conduction are different processes. Well, the way it's rolled suggests silver side up & I found an image on ebay that looks the same. It's better protected that way too.