Now you've got me researching R values for sleeping pads and air mattresses.

Air Mattresses can have an R Value of 1-5 depending on how well they convect inside. Mine is cheap and not rated for such things. I would guess it's better than 1.

The blue and yellow foam which is so common and popular has an R Value of about 1.36 with ultralight versions dipping down to 0.66 and 'winter' versions stretching to just above 2. Not as good as I'd have expected.

I read online that having a closed cell pad AND an air mattress provided awesome insulation...but I can't confirm that.

Of course the self inflating mattresses perform the best with down filled mattresses having R values of 8 or more...but the prices are 150 to 200 bucks.