What value is expressed as the resistance per inch in HVAC terminology?

In HVAC terminology, the resistance per inch value is expressed as "R." The R-value is a measure of thermal resistance, indicating how well a material insulates against heat flow. The unit of R is typically expressed as square feet times degrees Fahrenheit per British thermal unit (ft²·°F/BTU). When assessing insulation materials, knowing the R-value is crucial because it helps determine the effectiveness of thermal insulation in various applications, including walls, roofs, and floors. The higher the R-value, the better the material's insulating properties.

While other terms such as HTM, U, and Coefficient may relate to thermal properties, they do not specifically represent resistance per inch. HTM is often associated with heat transfer materials or heat transfer modeling, while U-value expresses thermal transmittance instead of resistance. Coefficient typically refers to various other properties, such as coefficients of thermal expansion, but does not denote resistance in this context.