R-value refers to a material’s thermal resistance, or how well it is able to retard heat flow. The R-value indicates the ability of a material to “resist” the flow of heat. The higher the R-value, the better an insulator will perform.
R-Value is the reciprocal or inverse of conductivity or conductance.
1/R = c (conductance)
1/R per inch = k (conductivity)
R-Value is important because it describes the capability of a given insulation product. Higher R-Value products will better resist heat flow, saving the building owner or occupants energy and as a result, money. Higher insulation value products save more money and are worth more in the long run.
R-Value works both in the winter to save heating costs and in the summer to save air conditioning costs.