Radiant Barrier in Zone 8 (Subarctic)
Radiant barriers do not have an R-value but reduce radiant heat gain. This page covers the effectiveness and application of radiant barriers in Climate Zone 8 (Subarctic).
Specifications
Radiant Barrier in Zone 8 — Guidance
Radiant barriers provide limited benefit in Climate Zone 8 (Subarctic) where heating rather than cooling is the dominant energy concern. Radiant barriers work by reflecting radiant heat, which is primarily a summer cooling benefit. In cold climates, the heat flow direction is from the warm interior outward, and this heat transfer is primarily conductive and convective rather than radiative. The DOE recommends investing in higher R-value bulk insulation rather than radiant barriers in zones 4 and above. If you have already achieved the recommended R-value for your attic and are looking for additional energy savings, consider air sealing improvements rather than a radiant barrier. However, if your home has significant solar heat gain issues during summer even in this cold climate zone, a radiant barrier could still provide modest cooling season benefits.
States in Zone 8
These states include areas within Climate Zone 8 where the Radiant Barrier requirements shown above apply. Click any state for its complete insulation recommendations.