R-Value Calculator

Understanding R-Values

R-value measures thermal resistance - the ability of insulation material to resist heat flow.

  • R-Value Definition Higher R-values indicate better insulating properties. R-value is measured in ft²·°F·h/BTU.
  • Material Properties Different materials have varying R-values per inch of thickness.
  • Thickness Impact R-value typically increases linearly with material thickness.
  • Climate Considerations Required R-values vary by climate zone and building component.

Common R-Values Per Inch

Fiberglass

R-2.9 to R-3.8 per inch

Cellulose

R-3.1 to R-3.7 per inch

Spray Foam

R-3.6 to R-6.5 per inch

Mineral Wool

R-3.0 to R-4.3 per inch

Installation Best Practices

  • Proper Installation Ensure no gaps or compression for maximum effectiveness.
  • Moisture Control Include vapor barriers when necessary to prevent moisture damage.
  • Ventilation Maintain proper ventilation to prevent condensation issues.
  • Multiple Layers Consider using multiple layers with staggered joints for better performance.