Understanding Wall R-Values
Wall R-values represent the total thermal resistance of all materials in a wall assembly.
- Layer Addition Total R-value is the sum of individual layer R-values.
- Material Properties Each material has a specific R-value per inch thickness.
- Air Spaces Air spaces contribute to total R-value but vary with orientation.
- Code Requirements Different climate zones require different minimum wall R-values.
Common Material R-Values
Drywall
R-0.45 to R-0.63 per inch
Fiberglass Batts
R-3.1 to R-3.4 per inch
Brick
R-0.2 per inch
Air Space
R-0.9 to R-1 (¾" or more)
Best Practices
- Continuous Insulation Minimize thermal bridging with continuous exterior insulation.
- Air Barriers Include proper air barriers to prevent heat loss through air leakage.
- Vapor Control Consider vapor permeability of materials in your climate zone.
- Installation Quality Proper installation is crucial for achieving rated R-values.