Does Reflectix “Big Bubble” insulation really achieve R-6?
I have seen several discussions here about bubble wrap insulation for ducts (some links below). However, they are all a couple years old, and they don’t seem to directly address one of Reflectix’s products. The older and smaller products were generally met with great skepticism because they claimed high R values without clarifying that the installation required an air gap between the duct and the bubble wrap.
I recently had new ducts installed with a new HVAC system, and my installer used Reflectix “Big Bubble” insulation directly around rigid metal trunks (and flex line for the runouts). From what I understand, this product differs from other bubble wraps in that it is thicker (~1 inch thick) and contains two layers of bubbles. This product specifically states on it in big red letters “R-8 WITH AIRSPACE” and “R-6.0 WITHOUT AIRSPACE.” The company’s website says “The product provides an R-8.0 when installed with a 0.75” air gap between the duct and the insulation, and R-6.0 when installed direct to the duct without a spacer.”
Since so many people seemed not to trust the claimed R values of other bubble wrap products, I’m wondering if anyone has any concerns with the claims about the “Big Bubble” product?