Thermal Transmittance vs. Thermal Resistance
Calculator for thermal transmittance (U) and thermal resistance (R). Thermal transmittance is the inverse of thermal resistance. For layered constructions, the overall thermal transmittance is 1 divided by the sum of individual thermal resistances.
Thermal Transmittance vs. Thermal Resistance
Thermal transmittance and thermal resistance are inversely related:
U = 1 / R (Equation 1)
Where:
- U = overall thermal transmittance (W/m² °C)
- R = overall thermal resistance (m² °C/W)
For layered constructions with multiple thermal resistances:
U = 1 / ΣRi (Equation 2)
Example - Heat Exchanger: U = 1 / (R_air film + R_condensate film + R_metal wall + R_product film)