Siding R-Value Calculator — Calculate Insulation Value of Siding Materials

Siding R-Value Calculator

Calculate the R-value (thermal resistance) of your siding with our comprehensive calculator. Determine insulation performance for different siding materials, thicknesses, and construction types.

Step 1: Siding Specifications

0.5″

Understanding R-Value

R-value measures thermal resistance – higher values mean better insulation. R-values are additive, so the total R-value is the sum of all material layers in your wall assembly.

Step 2: Wall Assembly

0.75″

About Air Spaces

Air spaces behind siding provide drainage and ventilation. A ¾” air space typically adds R-0.9 to thermal resistance. Proper ventilation helps prevent moisture issues and improves energy efficiency.

R-Value Calculation Results

Summary
Material Comparison
Breakdown

Total Wall Assembly R-Value

R-24.7
Fiber cement siding with 1″ foam sheathing and mineral wool insulation
Siding R-Value
R-0.6
Sheathing R-Value
R-5.0
Cavity Insulation
R-19.0
Air Space
R-0.9

Energy Efficiency Rating

Based on your R-value of R-24.7, your wall assembly provides good energy efficiency for most climate zones. Consider adding more insulation for colder climates.

Siding Material R-Value Comparison

Siding Material Thickness R-Value per inch Total R-Value Typical Use

R-Value Layer Breakdown

R-Value Formula

Total R-Value = Rsiding + Rsheathing + Rinsulation + Rair space + Rinterior finish

To calculate total R-value: Add the R-values of each component layer in your wall assembly. R-values are measured in ft²·°F·h/BTU (imperial) or m²·K/W (metric).

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