Thermal resistance, a measure of a material’s resistance to heat flow, is determined by dividing the temperature difference across a material by the heat flux (heat transfer per unit area). For example, if a 1-inch thick insulation sample maintains a 10F temperature difference between its surfaces while experiencing a heat flux of 1 BTU per hour per square foot, its thermal resistance is 10 Ffth/BTU. This principle applies across various materials, from insulation in buildings to clothing fabrics.
Understanding and quantifying this resistance is crucial for optimizing energy efficiency in buildings, designing effective thermal protection systems, and selecting appropriate materials for diverse applications. Historically, this concept has played a vital role in advancements like improved building insulation, leading to significant energy savings and reduced environmental impact. Accurate calculation facilitates informed decision-making in engineering and construction, contributing to sustainable practices and enhanced comfort.