Wall Calculator

R Value Calculator

Use this R Value Calculator to determine the effective R value and cost of wall assemblies quickly and easily.  Calculators for roofs and floors are also available.
Please visit this page on a PC to use the R Value Calculator.
Calculator-Wall

Calculation methods:

  • Overall R value of wood stud walls are calculated using the Parallel Path Method from ASHRAE Handbook of Fundamentals 2013 Chapter 27.
  • Overall R value of steel stud walls are calculated using the Modified Zone Method from ASHRAE Handbook of Fundamentals 2013 Chapter 27. Note: There is a stud spacing parameter adjustment applied for walls with high framing fractions.
    Other methods for calculating R value of metal studs include IECC U-Factor tables and ANSI test results. R values derived from these methods may be different than Ekotrope’s calculations.