Thermal Resistance Calculator
Free calculate thermal resistance, r-value, and heat transfer resistance. determine thermal resistance from thermal conductivity, thickness, and cross-sectional area.
Input Parameters
Insulation: 0.02-0.04 W/m·K, Wood: 0.1-0.2 W/m·K
Leave as 1 for R-value per unit area
Results
Enter parameters to calculate thermal resistance
Thermal Resistance Formula
Formula
R = L / (k × A)
For unit area (R-value):
R = L / k
Where:
- • R = thermal resistance (K/W or m²·K/W)
- • L = thickness (m)
- • k = thermal conductivity (W/m·K)
- • A = area (m²)
Common R-Values
- • Fiberglass (6"): R-19
- • Cellulose (6"): R-20
- • Spray foam (6"): R-21
- • Double pane window: R-2
- • Single pane window: R-1