What is K factor?
K factor is thermal conductivity (heat transferred per unit of time for unit area for a temperature gradient of one °F per unit length of heat path), Btu-in./h-ft.2-°F
“k”: Thermal conductivity, the amount of heat (Btu’s) transferred in 1 hour through 1 square foot of a homogeneous material 1 inch thick for a difference in temperature of 1°F. For example, the “k” for Durafoam DK1111 is 0.275 at 90°F. This means that for a 1 inch thickness there is a heat transfer of 0.275 Btu per hour per square foot for each degree difference in temperature between its two surfaces. Usually expressed in Btu-in./h-ft.2-°F in the insulation field. – John Bonforte, Sr.