In reflective insulation, the “R-value” refers to a measure of the insulation’s resistance to heat flow. The purpose of the insulation is to help the HVAC system run more efficiently by keeping the conditioned air at the proper temperature without leaking or being affected by the unconditioned air outside of the system, making heat flow resistance a key measurement. A higher R-value represents a greater resistance to heat flow.

R-values for reflective insulation are dependent on the amount of air space that is present between the reflective insulation material and the surface to which it is applied, such as a metal duct. Having an air gap is necessary for reflective insulation to be effective, and the amount of empty space in that gap impacts the insulation’s resistance to heat flow, therefore determining the R-value.

In cases where two layers of reflective insulation are installed, the R-value achieved will be higher than if only a single layer is used, provided that a proper air gap is present between both layers as well as the duct that is being covered.

When installing reflective insulation to achieve a certain R-value, an airtight tape seal is essential. To learn more about tape designed specifically for reflective insulation, visit