The R-value is a measure of thermal resistance, or ability of heat to transfer from hot to cold, through materials (such as insulation) and assemblies of materials (such as walls and floors). The higher the R-value, the more a material prevents heat transfer. R-value depends on materials' resistance to heat conduction, as well as the thickness and (for loose or porous material) any heat losses due to convection and radiative heat transfer.
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 direction2. The amount of air space in a closed cavity, on the reflective side of the product, in a building assemblageThis 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).