Now you have me anticipating some serious research, Mark.
You probably are ahead of me on this. I was thinking that when you run your test of assorted materials, it would be interesting to get readings on the non-insulated side liner, the roof and the windows. Sort of a baseline of what the stock camper insulation values are.
I'm thinking the windows are at least as big a heat loss as the bare side liner. Seems like I read somewhere that standard glass = R1
I hadn't yet put it in my "experimental plan", but yes, taking measurements of the soft-side with no insulation as a baseline will also be included. Thanks for the reminder.
Temperature measurements of surfaces other than the soft-side are a good idea...
....but one potential problem is from how IR thermometers work. They infer the temperature of the surface based on the infrared measured radiating from that surface. However, different surfaces radiate different amounts of IR radiation at the same temperature -- they have different "emissivity". I think that most surfaces are close-enough, otherwise an IR thermometer wouldn't be much good. But I think that shiny metal surfaces do have a big deviation from average emissivity -- that's why aluminum foil is good for reflecting radiant heat...and anything that reflects well doesn't radiate well. Like, if you have a piece of shiny metal and a piece of plastic at the same actual temperature, an IR thermometer will read that the plastic is warmer (apparently, that is) than the metal because the metal radiates less IR.
And I wonder if glass -- the windows -- also deviate from the emissivity found for most surfaces. I don't know...
Not being misled by data -- and drawing the wrong conclusions -- is important to me. I'd rather draw no conclusion -- "I don't know" -- than say something that's wrong. (For example: If I point the IR thermometer at the glass window and it reads as cooler than the soft-side, that implies that less heat is passing through it...or is it really just radiating less heat but is actually warmer than the soft-side...and if it's warmer that means that heat is passing through it faster -- it still transfers heat to the outside air by conduction-contact with the outside air.)
I'll do a little background reading on measuring temperature of surfaces with an IR thermometer. I'll still take the measurements of all surfaces anyway...but I may not share the results if I think they're misleading.