As they say, it really depends on the air space. Each layer is about a quarter inch thick and has an R-factor of about 1. Two layers thus has an R-factor of about 2. Add to that the R-factor of the glass and fleece and you get about 2.5 or 3, which isn't shabby at all.
It just seems to me that there are better ways of getting that same air space than to use Reflectix. I like the polystyrene because it is flat, uniform, somewhat flexible, and cheap. The walls of the Compact Jr I have don't have much bow to them so the flat sheets are easy to install. And unlike the Reflectix they have no pattern. Even so, I would like to cover it with something like elephant hide just to make it less susceptible to dings and gouges, and still be easy to clean.
Dana--- (I hope we're not stealing this thread) anyhoo, dings are the main reason I'm leaning away from polystyrene... After two days against a frozen window, the fleece is still pleasant to touch. (maybe I'm getting the R-15 factor Scamp
) So, I think I'm going to try that in a few spots on the Scamp- like behind the bunk/gaucho -- my back gets cold in the winter, also around the permanent bed. here's a couple shots. Larry