Hi AC,
I had a go at measuring the performance of bubble wrap on our double glazed low e windows back in 2005:
BubbleWrapPerformance
The results looked pretty good -- better than I would have expected by just saying the the bubble wrap adds about R1 to what is already there. Not sure if this is a flaw in the technique I used, or just that the bubble wrap did a bit better than expected.
Based on the double glazed low-e having an R value of about 3 (U of 0.33) and the bubble wrap adding R1, you would expect about a 25% drop in heat loss by adding the bubble wrap.
But, the measurements I took came out at about a 45% reduction in heat loss.
Anyone have a better way of measuring the actual performance?
I now have an IR thermal camera, which would make getting overall window temps easier.
It would be nice to know what the real number is.
Gary