39-14=25 so R=25
25+14=39
R+14=39
The R value or R-value, the measure of thermal resistance (K·m²/W) used in the building and construction industry
The R-value of insulating material is an indication of its effectiveness in reducing heat flow through walls, floor, and ceiling of a structure.
As in pie r squared? r = radius.
R value is a measure of the ability of a material to retard, or slow down, the movement of heat.