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Does foil bubble wrap insulation work?

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.

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Never Use This for Insulation...

Stay Away from Foil-Faced Bubble Wrap

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.) 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 for the "oversights" and "typographical errors" that appeared on their websites.

Blurring the line between product R-values and assembly R-values

Many of the manufacturers and distributors that publish exaggerated R-values deliberately blur the bright legal line that separates product R-values from assembly R-values. According to federal law, the R-value of an insulation product — for example, a piece of 1-inch thick polyisocyanurate — is the R-value of the insulation alone. That's the R-value which insulation manufacturers are required to report on their packaging and in their advertising; the requirement is spelled out in the Federal R-Value Rule, a law that applies to manufacturers, retailers, and builders. The R-value of a building assembly is something different. For example, if you build a wall with a layer of interior polyisocyanurate, followed by horizontal 1x4 strapping and drywall, the air space between the polyiso and the drywall has a measurable R-value. If you want to calculate the R-value of the entire wall assembly, you would need to calculate the R-value of the air space and add that R-value to the R-value of all the other layers. Once you've done that, you'll know your wall assembly R-value. Here's the key point: polyiso manufacturers can't claim the R-value of an air space in their labeling or advertising (unless the advertising makes a very clear distinction between the product R-value and the R-value of a hypothetical building assembly).

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Many of the manufacturers and distributors that publish exaggerated R-values deliberately blur the bright legal line that separates product R-values from assembly R-values.According to federal law, the R-value of an insulation product — for example, a piece of 1-inch thick polyisocyanurate — is the R-value of the insulation alone. That's the R-value which insulation manufacturers are required to report on their packaging and in their advertising; the requirement is spelled out in the Federal R-Value Rule, a law that applies to manufacturers, retailers, and builders.The R-value of a building assembly is something different. For example, if you build a wall with a layer of interior polyisocyanurate, followed by horizontal 1x4 strapping and drywall, the air space between the polyiso and the drywall has a measurable R-value. If you want to calculate the R-value of the entire wall assembly, you would need to calculate the R-value of the air space and add that R-value to the R-value of all the other layers. Once you've done that, you'll know your wall assembly R-value.Here's the key point: polyiso manufacturers can't claim the R-value of an air space in their labeling or advertising (unless the advertising makes a very clear distinction between the product R-value and the R-value of a hypothetical building assembly).

Product distributors are violating federal law

Fortunately, most (but not all) manufacturers of foil-faced bubble wrap have removed the blatant lies from their websites. Instead, manufacturers tempt the unwary with vague promises; for example, they claim that their bubble wrap "has a high R-value" or that it "resists the transfer of heat." The scoff-law websites with the greatest number of lies about foil-faced bubble wrap are those maintained by distributors — including a few large corporations like Home Depot, Ace Hardware, and Amazon — rather than those maintained by manufacturers. For example, Amazon claims that a type of foil-faced bubble wrap product manufactured by EcoFoil ("HVAC Duct Wrap Insulation") has an R-value of R-8. But a careful reading of the manufacturer's technical data sheet and the referenced ICC-ES Evaluation Report reveals that the R-8 value claim is based on an assembly that includes the R-value of a 2-inch air space. Similarly, Ace Hardware is advertising Reflectix, an R-1 foil-faced bubble wrap product, with a blurb that claims that the product has "R-values ranging from R-3.7 to R-21." That's a little like Starbucks saying that a cup of coffee is a satisfying meal — as long as you remember to accompany the coffee with a 12-inch submarine sandwich (not included).

Yes, a few manufacturers are still lying

Although the major manufacturers of foil-faced bubble wrap have (almost) cleaned up their act, some still include exaggerations on their websites. One manufacturer that trumpets exaggerated R-values is EcoFoil (a.k.a. rFoil, a.k.a. Covertech Fabricating). The EcoFoil website describes the company's duct wrap as an R-8 product, even though the R-8 claim is based on an assembly that includes an adjacent air space. The company also claims that "EcoFoil [foil-faced bubble wrap] under concrete insulation is superior to traditional, outdated forms of concrete floor insulation such as polystyrene or foam sheets." This statement is false. Elsewhere, EcoFoil claims that its 5/16-inch-thick bubble wrap product, which is called "Under Concrete Insulation," has an R-value of R-3.8. It does not. Another bad apple is Insulation4less, which retails a thin product called Prodex Total. On its website, the company states, "Prodex Total has a nominal thickness of 5 mm (13/64 inch) closed cell polyethylene foam covered on both sides with .0012 (00.03 mm) aluminum foil facing. ...R-value R-16 unaffected by humidity." Prodex may be unaffected by humidity — but it is seriously affected by gross exaggeration.

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These are not examples of victimless crimes; there are victims. One victim is a blogger who reports using this sub-slab assembly: "In basement, install Insul-Tarp over crushed rock, single layer of wire mesh, and Wirsbro [hydronic] tubing, pour concrete (pump hose will go through stairwell hole)." Unfortunately, Insul-Tarp has an R-value of R-2 or less. For years, however, the manufacturer of Insul-Tarp claimed that the product was rated at R-7 or more. The blogger who specified Insul-Tarp believed the false claims, which is why he wrote, "This is what the Insul-Tarp looks like. The exterior is some kind of tough fabric, then there are two layers of thin white foam, then a layer of bubble wrap. Hard to believe this can be equivalent of 2 inches of styrofoam." Indeed, it is hard to believe — so hard, in fact, that the Federal Trade Commission initiated court action that forced Meyer Enterprises, the manufacturer of Insul-Tarp, to stop making false claims. According to the FTC complaint, Meyer Enterprises "claimed Insul-Tarp's R-value is 7.54, but in reality Insul-Tarp's R-value could not be more than 2." Although the major manufacturers of foil-faced bubble wrap have (almost) cleaned up their act, some still include exaggerations on their websites.One manufacturer that trumpets exaggerated R-values is EcoFoil (a.k.a. rFoil, a.k.a. Covertech Fabricating). The EcoFoil website describes the company's duct wrap as an R-8 product, even though the R-8 claim is based on an assembly that includes an adjacent air space. The company also claims that "EcoFoil [foil-faced bubble wrap] under concrete insulation is superior to traditional, outdated forms of concrete floor insulation such as polystyrene or foam sheets." This statement is false.Elsewhere, EcoFoil claims that its 5/16-inch-thick bubble wrap product, which is called "Under Concrete Insulation," has an R-value of R-3.8. It does not.Another bad apple is Insulation4less, which retails a thin product called Prodex Total. On its website, the company states, "Prodex Total has a nominal thickness of 5 mm (13/64 inch) closed cell polyethylene foam covered on both sides with .0012 (00.03 mm) aluminum foil facing. ...R-value R-16 unaffected by humidity."Prodex may be unaffected by humidity — but it is seriously affected by gross exaggeration.These are not examples of victimless crimes; there are victims. One victim is a blogger who reports using this sub-slab assembly: "In basement, install Insul-Tarp over crushed rock, single layer of wire mesh, and Wirsbro [hydronic] tubing, pour concrete (pump hose will go through stairwell hole)."Unfortunately, Insul-Tarp has an R-value of R-2 or less. For years, however, the manufacturer of Insul-Tarp claimed that the product was rated at R-7 or more. The blogger who specified Insul-Tarp believed the false claims, which is why he wrote, "This is what the Insul-Tarp looks like. The exterior is some kind of tough fabric, then there are two layers of thin white foam, then a layer of bubble wrap. Hard to believe this can be equivalent of 2 inches of styrofoam."Indeed, it is hard to believe — so hard, in fact, that the Federal Trade Commission initiated court action that forced Meyer Enterprises, the manufacturer of Insul-Tarp, to stop making false claims. According to the FTC complaint, Meyer Enterprises "claimed Insul-Tarp's R-value is 7.54, but in reality Insul-Tarp's R-value could not be more than 2."

Duct insulation scams

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