Most brands of foil-faced bubble wrap are only 3/8 inch thick or less, and have an R-value of only 1.0 or 1.1. Since the product often costs more per square foot than 1-inch thick rigid foam rated at R-5, why would anyone use bubble wrap as insulation?
The R-value of foil-faced bubble wrap is so low that it has few, if any, advantages over rigid foam. Of course, the product’s foil facing can be used as a radiant barrier — but if you want a radiant barrier, cheaper products are available. (The bubble wrap layer is unnecessary, since it adds cost to the material without adding any useful thermal performance.)
Exaggerated R-value claims
Since the main benefit from foil-faced bubble wrap is due to its radiant-barrier facing, the product is basically worthless unless it faces an air space. A decade ago, when I was the editor of Energy Design Update, I noticed that many manufacturers of foil-faced bubble wrap were promoting their products for use under concrete slabs on grade. In this application, the shiny foil is clearly not facing an air space, so the exaggerated R-value claims made by bubble-wrap manufacturers were particularly outrageous. My article exposing the bubble-wrap scammers appeared in the September 2003 issue of EDU.
In that article, I reported that one manufacturer, WE International, made absurd claims about a thin (5/16-inch) product called Concrete Barrier rFoil. The manufacturer’s website boasted, “Concrete Barrier can serve three purposes underneath concrete: R-10 insulation, a vapor barrier and a radon barrier. … How does it compare to 2-inch foam board? It works just as well.”
Similarly, Insulation Solutions, the manufacturer of a 3/8-inch thick product called Insul-Tarp, claimed that the flexible tarp has an “R-value equivalent” rating of R-5 to R-10.
After these lies were publicized, three manufacturers wrote letters to EDU apologizing…