What is the recommended R-value for walls in energy-efficient insulation?

The recommended R-value for walls in energy-efficient insulation is R-19. This level of insulation is typically suitable for exterior walls in climates that experience a range of temperatures, helping to maintain comfortable indoor temperatures and increase energy efficiency. R-values represent the insulation's effectiveness at resisting heat flow, with higher values indicating better insulating properties. While the other options may pertain to insulation for different applications or climate zones – for instance, R-30 is usually recommended for ceilings or attics, and R-11 might be considered for interior walls – R-19 specifically provides the optimum balance for exterior wall insulation in many regions, promoting energy savings and comfort.