Thermal transmittance is a heat property associated with resistance to heat flow. Which term describes this resistance?

Thermal transmittance is a heat property associated with resistance to heat flow. Which term describes this resistance?

• A. Thermal transmittance
• B. Thermal resistance
• C. Heat capacity
• D. Thermal mass

Answer: (B)

Thermal resistance is the measure of how much a material or assembly resists heat flow. It quantifies the difficulty of heat moving through, so a higher resistance means less heat transfer and better insulation. In practice, thermal resistance (R) is the reciprocal of thermal transmittance (U); U tells you how much heat passes per area per degree of temperature difference, so a lower U corresponds to a higher R. Heat capacity and thermal mass describe how much heat a material can store or how its temperature changes with added heat, not how hard heat flows through. Therefore, the resistance to heat flow is described by thermal resistance.

Thermal resistance is the measure of how much a material or assembly resists heat flow. It quantifies the difficulty of heat moving through, so a higher resistance means less heat transfer and better insulation. In practice, thermal resistance (R) is the reciprocal of thermal transmittance (U); U tells you how much heat passes per area per degree of temperature difference, so a lower U corresponds to a higher R. Heat capacity and thermal mass describe how much heat a material can store or how its temperature changes with added heat, not how hard heat flows through. Therefore, the resistance to heat flow is described by thermal resistance.