R-value(redirected from R value)
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An index of the ability of a substance or material to retard the flow of heat; higher numerical values correspond to higher insulating ability.
A unit of thermal resistance. A material’s R-value is a measure of the effectiveness of the material in stopping the flow of heat through it. The higher a material’s Rvalue, the greater its insulating properties and the slower the heat flow through it. Examples of higher R-values for residential buildings: R-50 ceilings, R-21 walls, and R-30 floors.
A measure of the thermal resistance of a material or component.