What is an R-value?
An R-value is an assigned number derived from a specific testing procedure (or calculation) to determine a materials (or building assemblage) “resistance to conductive heat transfer”. The higher the R-value, the more resistant a material (or building assemblage) is to conductive heat transfer. Reflectix® can provide verification for all R-values stated for all products and applications.
What about R-values for a Reflective Insulation, and why do they vary with application?
R-values for reflective insulations are dependent on two (primary) criteria:
1. Heat flow direction
2. The amount of air space in a closed cavity, on the reflective side of the product, in a building assemblage
This is the reason our product has different R-values for different applications (varying amount of air space and heat flow directions).
What is meant by the terms “Up”, “Down” and “Horizontal” Heat Flow?
These terms are related to heat flow directions. They are a part of the criteria utilized in R-value testing. For example, when testing a floor assemblage, heat flow down is tested. When testing for a wall system, heat flow horizontal is tested (same for all conductive heat transfer insulations).
If you install 2 layers of a Reflective Insulation, does the R-value double?
With multiple layers of product and airspaces between each layer, enhanced performance will be gained. If the product is simply “doubled” (with no air space between the layers), a very minimal benefit is obtained (R-1.1 (per layer) for the Reflective/Double Bubble product).